diff --git a/docs/implementation/task-d-enquiry-production.md b/docs/implementation/task-d-enquiry-production.md
new file mode 100644
index 0000000..afa20ad
--- /dev/null
+++ b/docs/implementation/task-d-enquiry-production.md
@@ -0,0 +1,118 @@
+# Task D: Enquiry Production Module
+
+## 1. Files Added
+
+- `src/app/api/crm/enquiries/route.ts`
+- `src/app/api/crm/enquiries/[id]/route.ts`
+- `src/app/api/crm/enquiries/[id]/followups/route.ts`
+- `src/app/api/crm/enquiries/[id]/followups/[followupId]/route.ts`
+- `src/features/crm/enquiries/api/types.ts`
+- `src/features/crm/enquiries/api/service.ts`
+- `src/features/crm/enquiries/api/queries.ts`
+- `src/features/crm/enquiries/api/mutations.ts`
+- `src/features/crm/enquiries/schemas/enquiry.schema.ts`
+- `src/features/crm/enquiries/server/service.ts`
+- `src/features/crm/enquiries/components/enquiry-status-badge.tsx`
+- `src/features/crm/enquiries/components/enquiry-form-sheet.tsx`
+- `src/features/crm/enquiries/components/followup-form-sheet.tsx`
+- `src/features/crm/enquiries/components/enquiry-cell-action.tsx`
+- `src/features/crm/enquiries/components/enquiry-columns.tsx`
+- `src/features/crm/enquiries/components/enquiries-table.tsx`
+- `src/features/crm/enquiries/components/enquiry-listing.tsx`
+- `src/features/crm/enquiries/components/enquiry-followups-tab.tsx`
+- `src/features/crm/enquiries/components/enquiry-detail.tsx`
+- `drizzle/0003_blushing_bruce_banner.sql`
+- `drizzle/meta/0003_snapshot.json`
+
+## 2. Files Modified
+
+- `src/app/dashboard/crm/enquiries/page.tsx`
+- `src/app/dashboard/crm/enquiries/[id]/page.tsx`
+- `src/app/dashboard/crm/customers/[id]/page.tsx`
+- `src/features/crm/customers/api/types.ts`
+- `src/features/crm/customers/components/customer-detail.tsx`
+- `src/db/schema.ts`
+- `src/db/seeds/foundation.seed.ts`
+- `src/lib/auth/rbac.ts`
+- `src/lib/searchparams.ts`
+- `drizzle/meta/_journal.json`
+
+## 3. Schema Added
+
+- `crm_enquiries`
+  - organization-scoped sales opportunity master
+  - customer/contact linkage, project context, pricing expectation, probability, hot-project flag, and soft-delete columns
+  - unique `(organization_id, code)` for document-sequenced enquiry codes
+- `crm_enquiry_followups`
+  - organization-scoped timeline items under enquiry
+  - follow-up type, contact linkage, outcome, next follow-up date, next action, and soft-delete columns
+
+## 4. API Routes Added
+
+- `GET /api/crm/enquiries`
+- `POST /api/crm/enquiries`
+- `GET /api/crm/enquiries/[id]`
+- `PATCH /api/crm/enquiries/[id]`
+- `DELETE /api/crm/enquiries/[id]`
+- `GET /api/crm/enquiries/[id]/followups`
+- `POST /api/crm/enquiries/[id]/followups`
+- `PATCH /api/crm/enquiries/[id]/followups/[followupId]`
+- `DELETE /api/crm/enquiries/[id]/followups/[followupId]`
+
+## 5. UI Routes Completed
+
+- `/dashboard/crm/enquiries`
+  - production list with React Query, nuqs filters, create button, edit/view/delete actions
+  - filters: search, status, product type, priority, branch, customer
+- `/dashboard/crm/enquiries/[id]`
+  - detail page with tabs: Overview, Follow-ups, Activity, Related Quotations Placeholder
+- `/dashboard/crm/customers/[id]`
+  - related documents tab now shows real linked enquiries for that customer
+
+## 6. Permissions Used
+
+- `crm.enquiry.read`
+- `crm.enquiry.create`
+- `crm.enquiry.update`
+- `crm.enquiry.delete`
+- `crm.enquiry.followup.read`
+- `crm.enquiry.followup.create`
+- `crm.enquiry.followup.update`
+- `crm.enquiry.followup.delete`
+
+Admin defaults now include enquiry and follow-up permissions. Regular users inherit read permissions only unless additional permissions are granted.
+
+## 7. Audit Integration
+
+- enquiry create/update/delete writes to `tr_audit_logs` with `entityType = crm_enquiry`
+- follow-up create/update/delete writes to `tr_audit_logs` with `entityType = crm_enquiry_followup`
+- enquiry detail activity tab merges enquiry audit and follow-up audit entries, then resolves actor names from `users`
+
+## 8. Document Sequence Integration
+
+- enquiry create uses `generateNextDocumentCode({ documentType: 'enquiry' })`
+- branch-specific sequence is honored when `branchId` is provided
+- foundation seed now includes `crm_followup_type` options so follow-up forms do not hardcode those values
+
+## 9. Customer/Contact Integration
+
+- enquiry create/update validates that customer belongs to the active organization
+- enquiry contact must belong to the same organization and selected customer
+- follow-up contact must belong to the same organization and the enquiry's customer
+- enquiry form customer dropdown is sourced from production customer data
+- contact dropdown is filtered by selected customer
+- customer detail route now shows related enquiries in the related-documents tab
+
+## 10. Remaining Risks
+
+- there are still no database foreign keys between enquiry tables and customer/contact tables; organization scoping is enforced in application logic
+- form date fields currently use `YYYY-MM-DD` text inputs because the project field wrapper does not expose a native date mode
+- customer detail shows linked enquiries, but there is not yet a dedicated customer-side enquiry table with pagination
+- follow-up activity relies on audit payload contents for relation tracing, not a dedicated combined activity view
+
+## 11. Task E Readiness
+
+- enquiry production backbone is ready for quotation creation and linkage
+- customer, contact, and enquiry lifecycles now share the same foundation patterns: org scope, branch validation, master options, document sequence, and audit logging
+- enquiry detail already has a stable placeholder tab for quotation integration
+- follow-up timeline and customer-related enquiry surfacing are in place for downstream sales workflow expansion
diff --git a/drizzle/0003_blushing_bruce_banner.sql b/drizzle/0003_blushing_bruce_banner.sql
new file mode 100644
index 0000000..9abc1cc
--- /dev/null
+++ b/drizzle/0003_blushing_bruce_banner.sql
@@ -0,0 +1,50 @@
+CREATE TABLE "crm_enquiries" (
+	"id" text PRIMARY KEY NOT NULL,
+	"organization_id" text NOT NULL,
+	"branch_id" text,
+	"code" text NOT NULL,
+	"customer_id" text NOT NULL,
+	"contact_id" text,
+	"title" text NOT NULL,
+	"description" text,
+	"requirement" text,
+	"project_name" text,
+	"project_location" text,
+	"product_type" text NOT NULL,
+	"status" text NOT NULL,
+	"priority" text NOT NULL,
+	"lead_channel" text,
+	"estimated_value" double precision,
+	"chance_percent" integer,
+	"expected_close_date" timestamp with time zone,
+	"competitor" text,
+	"source" text,
+	"notes" text,
+	"is_hot_project" boolean DEFAULT false NOT NULL,
+	"is_active" boolean DEFAULT true NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"deleted_at" timestamp with time zone,
+	"created_by" text NOT NULL,
+	"updated_by" text NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE "crm_enquiry_followups" (
+	"id" text PRIMARY KEY NOT NULL,
+	"organization_id" text NOT NULL,
+	"enquiry_id" text NOT NULL,
+	"followup_date" timestamp with time zone NOT NULL,
+	"followup_type" text NOT NULL,
+	"contact_id" text,
+	"outcome" text,
+	"notes" text,
+	"next_followup_date" timestamp with time zone,
+	"next_action" text,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"updated_at" timestamp with time zone DEFAULT now() NOT NULL,
+	"deleted_at" timestamp with time zone,
+	"created_by" text NOT NULL,
+	"updated_by" text NOT NULL
+);
+--> statement-breakpoint
+CREATE UNIQUE INDEX "crm_enquiries_org_code_idx" ON "crm_enquiries" USING btree ("organization_id","code");
\ No newline at end of file
diff --git a/drizzle/meta/0003_snapshot.json b/drizzle/meta/0003_snapshot.json
new file mode 100644
index 0000000..b68640c
--- /dev/null
+++ b/drizzle/meta/0003_snapshot.json
@@ -0,0 +1,1290 @@
+{
+  "id": "7f3502c2-ddb7-47cd-bc78-0510a67ceded",
+  "prevId": "9f3af9b8-d774-40bb-8b24-29b06332b453",
+  "version": "7",
+  "dialect": "postgresql",
+  "tables": {
+    "public.crm_customer_contacts": {
+      "name": "crm_customer_contacts",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "customer_id": {
+          "name": "customer_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "position": {
+          "name": "position",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "department": {
+          "name": "department",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "phone": {
+          "name": "phone",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "mobile": {
+          "name": "mobile",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "email": {
+          "name": "email",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "is_primary": {
+          "name": "is_primary",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": false
+        },
+        "notes": {
+          "name": "notes",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "is_active": {
+          "name": "is_active",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "deleted_at": {
+          "name": "deleted_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_by": {
+          "name": "created_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "updated_by": {
+          "name": "updated_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.crm_customers": {
+      "name": "crm_customers",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "branch_id": {
+          "name": "branch_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "code": {
+          "name": "code",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "abbr": {
+          "name": "abbr",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "tax_id": {
+          "name": "tax_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "customer_type": {
+          "name": "customer_type",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "customer_status": {
+          "name": "customer_status",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "address": {
+          "name": "address",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "province": {
+          "name": "province",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "district": {
+          "name": "district",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "sub_district": {
+          "name": "sub_district",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "postal_code": {
+          "name": "postal_code",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "country": {
+          "name": "country",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "phone": {
+          "name": "phone",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "fax": {
+          "name": "fax",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "email": {
+          "name": "email",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "website": {
+          "name": "website",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "lead_channel": {
+          "name": "lead_channel",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "customer_group": {
+          "name": "customer_group",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "notes": {
+          "name": "notes",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "is_active": {
+          "name": "is_active",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "deleted_at": {
+          "name": "deleted_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_by": {
+          "name": "created_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "updated_by": {
+          "name": "updated_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {
+        "crm_customers_org_code_idx": {
+          "name": "crm_customers_org_code_idx",
+          "columns": [
+            {
+              "expression": "organization_id",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "code",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": true,
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.crm_enquiries": {
+      "name": "crm_enquiries",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "branch_id": {
+          "name": "branch_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "code": {
+          "name": "code",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "customer_id": {
+          "name": "customer_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "contact_id": {
+          "name": "contact_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "title": {
+          "name": "title",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "description": {
+          "name": "description",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "requirement": {
+          "name": "requirement",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "project_name": {
+          "name": "project_name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "project_location": {
+          "name": "project_location",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "product_type": {
+          "name": "product_type",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "status": {
+          "name": "status",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "priority": {
+          "name": "priority",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "lead_channel": {
+          "name": "lead_channel",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "estimated_value": {
+          "name": "estimated_value",
+          "type": "double precision",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "chance_percent": {
+          "name": "chance_percent",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "expected_close_date": {
+          "name": "expected_close_date",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "competitor": {
+          "name": "competitor",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "source": {
+          "name": "source",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "notes": {
+          "name": "notes",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "is_hot_project": {
+          "name": "is_hot_project",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": false
+        },
+        "is_active": {
+          "name": "is_active",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "deleted_at": {
+          "name": "deleted_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_by": {
+          "name": "created_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "updated_by": {
+          "name": "updated_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {
+        "crm_enquiries_org_code_idx": {
+          "name": "crm_enquiries_org_code_idx",
+          "columns": [
+            {
+              "expression": "organization_id",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "code",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": true,
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.crm_enquiry_followups": {
+      "name": "crm_enquiry_followups",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "enquiry_id": {
+          "name": "enquiry_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "followup_date": {
+          "name": "followup_date",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "followup_type": {
+          "name": "followup_type",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "contact_id": {
+          "name": "contact_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "outcome": {
+          "name": "outcome",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "notes": {
+          "name": "notes",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "next_followup_date": {
+          "name": "next_followup_date",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "next_action": {
+          "name": "next_action",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "deleted_at": {
+          "name": "deleted_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_by": {
+          "name": "created_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "updated_by": {
+          "name": "updated_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.document_sequences": {
+      "name": "document_sequences",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "branch_id": {
+          "name": "branch_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "''"
+        },
+        "document_type": {
+          "name": "document_type",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "prefix": {
+          "name": "prefix",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "period": {
+          "name": "period",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "current_number": {
+          "name": "current_number",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true,
+          "default": 0
+        },
+        "padding_length": {
+          "name": "padding_length",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true,
+          "default": 3
+        },
+        "is_active": {
+          "name": "is_active",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {
+        "document_sequences_org_doc_period_branch_idx": {
+          "name": "document_sequences_org_doc_period_branch_idx",
+          "columns": [
+            {
+              "expression": "organization_id",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "document_type",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "period",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "branch_id",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": true,
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.memberships": {
+      "name": "memberships",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "user_id": {
+          "name": "user_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "role": {
+          "name": "role",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "'user'"
+        },
+        "business_role": {
+          "name": "business_role",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "'viewer'"
+        },
+        "permissions": {
+          "name": "permissions",
+          "type": "text[]",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "'{}'"
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.ms_options": {
+      "name": "ms_options",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "category": {
+          "name": "category",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "code": {
+          "name": "code",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "label": {
+          "name": "label",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "value": {
+          "name": "value",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "parent_id": {
+          "name": "parent_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "sort_order": {
+          "name": "sort_order",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": true,
+          "default": 0
+        },
+        "is_active": {
+          "name": "is_active",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": true
+        },
+        "metadata": {
+          "name": "metadata",
+          "type": "jsonb",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "deleted_at": {
+          "name": "deleted_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {
+        "ms_options_org_category_code_idx": {
+          "name": "ms_options_org_category_code_idx",
+          "columns": [
+            {
+              "expression": "organization_id",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "category",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            },
+            {
+              "expression": "code",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": true,
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.organizations": {
+      "name": "organizations",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "slug": {
+          "name": "slug",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "image_url": {
+          "name": "image_url",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "plan": {
+          "name": "plan",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "'free'"
+        },
+        "created_by": {
+          "name": "created_by",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {
+        "organizations_slug_idx": {
+          "name": "organizations_slug_idx",
+          "columns": [
+            {
+              "expression": "slug",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": true,
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.products": {
+      "name": "products",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "integer",
+          "primaryKey": true,
+          "notNull": true,
+          "identity": {
+            "type": "always",
+            "name": "products_id_seq",
+            "schema": "public",
+            "increment": "1",
+            "startWith": "1",
+            "minValue": "1",
+            "maxValue": "2147483647",
+            "cache": "1",
+            "cycle": false
+          }
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "category": {
+          "name": "category",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "description": {
+          "name": "description",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "photo_url": {
+          "name": "photo_url",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "price": {
+          "name": "price",
+          "type": "double precision",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.tr_audit_logs": {
+      "name": "tr_audit_logs",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "organization_id": {
+          "name": "organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "branch_id": {
+          "name": "branch_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "user_id": {
+          "name": "user_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "entity_type": {
+          "name": "entity_type",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "entity_id": {
+          "name": "entity_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "action": {
+          "name": "action",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "before_data": {
+          "name": "before_data",
+          "type": "jsonb",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "after_data": {
+          "name": "after_data",
+          "type": "jsonb",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "request_id": {
+          "name": "request_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.users": {
+      "name": "users",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "text",
+          "primaryKey": true,
+          "notNull": true
+        },
+        "name": {
+          "name": "name",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "email": {
+          "name": "email",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "password_hash": {
+          "name": "password_hash",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "system_role": {
+          "name": "system_role",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "'user'"
+        },
+        "image": {
+          "name": "image",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "active_organization_id": {
+          "name": "active_organization_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp with time zone",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {
+        "users_email_idx": {
+          "name": "users_email_idx",
+          "columns": [
+            {
+              "expression": "email",
+              "isExpression": false,
+              "asc": true,
+              "nulls": "last"
+            }
+          ],
+          "isUnique": true,
+          "concurrently": false,
+          "method": "btree",
+          "with": {}
+        }
+      },
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {},
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    }
+  },
+  "enums": {},
+  "schemas": {},
+  "sequences": {},
+  "roles": {},
+  "policies": {},
+  "views": {},
+  "_meta": {
+    "columns": {},
+    "schemas": {},
+    "tables": {}
+  }
+}
\ No newline at end of file
diff --git a/drizzle/meta/_journal.json b/drizzle/meta/_journal.json
index cadfc07..88f0f6c 100644
--- a/drizzle/meta/_journal.json
+++ b/drizzle/meta/_journal.json
@@ -22,6 +22,13 @@
       "when": 1781498575433,
       "tag": "0002_plain_anthem",
       "breakpoints": true
+    },
+    {
+      "idx": 3,
+      "version": "7",
+      "when": 1781505431077,
+      "tag": "0003_blushing_bruce_banner",
+      "breakpoints": true
     }
   ]
 }
\ No newline at end of file
diff --git a/src/app/api/crm/enquiries/[id]/followups/[followupId]/route.ts b/src/app/api/crm/enquiries/[id]/followups/[followupId]/route.ts
new file mode 100644
index 0000000..ef6466e
--- /dev/null
+++ b/src/app/api/crm/enquiries/[id]/followups/[followupId]/route.ts
@@ -0,0 +1,124 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { z } from 'zod';
+import { auditDelete, auditUpdate } from '@/features/foundation/audit-log/service';
+import {
+  listEnquiryFollowups,
+  softDeleteEnquiryFollowup,
+  updateEnquiryFollowup
+} from '@/features/crm/enquiries/server/service';
+import { enquiryFollowupSchema } from '@/features/crm/enquiries/schemas/enquiry.schema';
+import { PERMISSIONS } from '@/lib/auth/rbac';
+import { AuthError, requireOrganizationAccess } from '@/lib/auth/session';
+
+type Params = {
+  params: Promise<{ id: string; followupId: string }>;
+};
+
+const followupRequestSchema = enquiryFollowupSchema.extend({
+  contactId: z.string().nullable().optional(),
+  nextFollowupDate: z.string().nullable().optional()
+});
+
+export async function PATCH(request: NextRequest, { params }: Params) {
+  try {
+    const { id, followupId } = await params;
+    const { organization, session } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryFollowupUpdate
+    });
+    const payload = followupRequestSchema.parse(await request.json());
+    const before = (await listEnquiryFollowups(id, organization.id)).find(
+      (item) => item.id === followupId
+    );
+
+    if (!before) {
+      return NextResponse.json({ message: 'Follow-up not found' }, { status: 404 });
+    }
+
+    const updated = await updateEnquiryFollowup(
+      id,
+      followupId,
+      organization.id,
+      session.user.id,
+      payload
+    );
+
+    await auditUpdate({
+      organizationId: organization.id,
+      userId: session.user.id,
+      entityType: 'crm_enquiry_followup',
+      entityId: followupId,
+      beforeData: before,
+      afterData: updated
+    });
+
+    return NextResponse.json({
+      success: true,
+      message: 'Enquiry follow-up updated successfully',
+      followup: updated
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof z.ZodError) {
+      return NextResponse.json(
+        { message: error.issues[0]?.message ?? 'Invalid payload' },
+        { status: 400 }
+      );
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to update enquiry follow-up' }, { status: 500 });
+  }
+}
+
+export async function DELETE(_request: NextRequest, { params }: Params) {
+  try {
+    const { id, followupId } = await params;
+    const { organization, session } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryFollowupDelete
+    });
+    const before = (await listEnquiryFollowups(id, organization.id)).find(
+      (item) => item.id === followupId
+    );
+
+    if (!before) {
+      return NextResponse.json({ message: 'Follow-up not found' }, { status: 404 });
+    }
+
+    const updated = await softDeleteEnquiryFollowup(
+      id,
+      followupId,
+      organization.id,
+      session.user.id
+    );
+
+    await auditDelete({
+      organizationId: organization.id,
+      userId: session.user.id,
+      entityType: 'crm_enquiry_followup',
+      entityId: followupId,
+      beforeData: before,
+      afterData: updated
+    });
+
+    return NextResponse.json({
+      success: true,
+      message: 'Enquiry follow-up deleted successfully'
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to delete enquiry follow-up' }, { status: 500 });
+  }
+}
diff --git a/src/app/api/crm/enquiries/[id]/followups/route.ts b/src/app/api/crm/enquiries/[id]/followups/route.ts
new file mode 100644
index 0000000..0cd69b4
--- /dev/null
+++ b/src/app/api/crm/enquiries/[id]/followups/route.ts
@@ -0,0 +1,91 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { z } from 'zod';
+import { auditCreate } from '@/features/foundation/audit-log/service';
+import {
+  createEnquiryFollowup,
+  listEnquiryFollowups
+} from '@/features/crm/enquiries/server/service';
+import { enquiryFollowupSchema } from '@/features/crm/enquiries/schemas/enquiry.schema';
+import { PERMISSIONS } from '@/lib/auth/rbac';
+import { AuthError, requireOrganizationAccess } from '@/lib/auth/session';
+
+type Params = {
+  params: Promise<{ id: string }>;
+};
+
+const followupRequestSchema = enquiryFollowupSchema.extend({
+  contactId: z.string().nullable().optional(),
+  nextFollowupDate: z.string().nullable().optional()
+});
+
+export async function GET(_request: NextRequest, { params }: Params) {
+  try {
+    const { id } = await params;
+    const { organization } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryFollowupRead
+    });
+    const items = await listEnquiryFollowups(id, organization.id);
+
+    return NextResponse.json({
+      success: true,
+      time: new Date().toISOString(),
+      message: 'Enquiry follow-ups loaded successfully',
+      items
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to load enquiry follow-ups' }, { status: 500 });
+  }
+}
+
+export async function POST(request: NextRequest, { params }: Params) {
+  try {
+    const { id } = await params;
+    const { organization, session } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryFollowupCreate
+    });
+    const payload = followupRequestSchema.parse(await request.json());
+    const created = await createEnquiryFollowup(id, organization.id, session.user.id, payload);
+
+    await auditCreate({
+      organizationId: organization.id,
+      userId: session.user.id,
+      entityType: 'crm_enquiry_followup',
+      entityId: created.id,
+      afterData: created
+    });
+
+    return NextResponse.json(
+      {
+        success: true,
+        message: 'Enquiry follow-up created successfully',
+        followup: created
+      },
+      { status: 201 }
+    );
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof z.ZodError) {
+      return NextResponse.json(
+        { message: error.issues[0]?.message ?? 'Invalid payload' },
+        { status: 400 }
+      );
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to create enquiry follow-up' }, { status: 500 });
+  }
+}
diff --git a/src/app/api/crm/enquiries/[id]/route.ts b/src/app/api/crm/enquiries/[id]/route.ts
new file mode 100644
index 0000000..510465e
--- /dev/null
+++ b/src/app/api/crm/enquiries/[id]/route.ts
@@ -0,0 +1,137 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { z } from 'zod';
+import { auditDelete, auditUpdate } from '@/features/foundation/audit-log/service';
+import {
+  getEnquiryActivity,
+  getEnquiryDetail,
+  softDeleteEnquiry,
+  updateEnquiry
+} from '@/features/crm/enquiries/server/service';
+import { enquirySchema } from '@/features/crm/enquiries/schemas/enquiry.schema';
+import { PERMISSIONS } from '@/lib/auth/rbac';
+import { AuthError, requireOrganizationAccess } from '@/lib/auth/session';
+
+type Params = {
+  params: Promise<{ id: string }>;
+};
+
+const enquiryRequestSchema = enquirySchema.extend({
+  contactId: z.string().nullable().optional(),
+  branchId: z.string().nullable().optional(),
+  leadChannel: z.string().nullable().optional(),
+  estimatedValue: z.number().nullable().optional(),
+  chancePercent: z.number().nullable().optional(),
+  expectedCloseDate: z.string().nullable().optional()
+});
+
+export async function GET(_request: NextRequest, { params }: Params) {
+  try {
+    const { id } = await params;
+    const { organization } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryRead
+    });
+    const [enquiry, activity] = await Promise.all([
+      getEnquiryDetail(id, organization.id),
+      getEnquiryActivity(id, organization.id)
+    ]);
+
+    return NextResponse.json({
+      success: true,
+      time: new Date().toISOString(),
+      message: 'Enquiry loaded successfully',
+      enquiry,
+      activity
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to load enquiry' }, { status: 500 });
+  }
+}
+
+export async function PATCH(request: NextRequest, { params }: Params) {
+  try {
+    const { id } = await params;
+    const { organization, session } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryUpdate
+    });
+    const payload = enquiryRequestSchema.parse(await request.json());
+    const before = await getEnquiryDetail(id, organization.id);
+    const updated = await updateEnquiry(id, organization.id, session.user.id, payload);
+
+    await auditUpdate({
+      organizationId: organization.id,
+      branchId: updated.branchId,
+      userId: session.user.id,
+      entityType: 'crm_enquiry',
+      entityId: id,
+      beforeData: before,
+      afterData: updated
+    });
+
+    return NextResponse.json({
+      success: true,
+      message: 'Enquiry updated successfully',
+      enquiry: updated
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof z.ZodError) {
+      return NextResponse.json(
+        { message: error.issues[0]?.message ?? 'Invalid payload' },
+        { status: 400 }
+      );
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to update enquiry' }, { status: 500 });
+  }
+}
+
+export async function DELETE(_request: NextRequest, { params }: Params) {
+  try {
+    const { id } = await params;
+    const { organization, session } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryDelete
+    });
+    const before = await getEnquiryDetail(id, organization.id);
+    const updated = await softDeleteEnquiry(id, organization.id, session.user.id);
+
+    await auditDelete({
+      organizationId: organization.id,
+      branchId: updated.branchId,
+      userId: session.user.id,
+      entityType: 'crm_enquiry',
+      entityId: id,
+      beforeData: before,
+      afterData: updated
+    });
+
+    return NextResponse.json({
+      success: true,
+      message: 'Enquiry deleted successfully'
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to delete enquiry' }, { status: 500 });
+  }
+}
diff --git a/src/app/api/crm/enquiries/route.ts b/src/app/api/crm/enquiries/route.ts
new file mode 100644
index 0000000..08f5999
--- /dev/null
+++ b/src/app/api/crm/enquiries/route.ts
@@ -0,0 +1,111 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { z } from 'zod';
+import { auditCreate } from '@/features/foundation/audit-log/service';
+import { createEnquiry, listEnquiries } from '@/features/crm/enquiries/server/service';
+import { enquirySchema } from '@/features/crm/enquiries/schemas/enquiry.schema';
+import { PERMISSIONS } from '@/lib/auth/rbac';
+import { AuthError, requireOrganizationAccess } from '@/lib/auth/session';
+
+const enquiryRequestSchema = enquirySchema.extend({
+  contactId: z.string().nullable().optional(),
+  branchId: z.string().nullable().optional(),
+  leadChannel: z.string().nullable().optional(),
+  estimatedValue: z.number().nullable().optional(),
+  chancePercent: z.number().nullable().optional(),
+  expectedCloseDate: z.string().nullable().optional()
+});
+
+export async function GET(request: NextRequest) {
+  try {
+    const { organization } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryRead
+    });
+    const { searchParams } = request.nextUrl;
+    const page = Number(searchParams.get('page') ?? 1);
+    const limit = Number(searchParams.get('limit') ?? 10);
+    const search = searchParams.get('search') ?? undefined;
+    const status = searchParams.get('status') ?? undefined;
+    const productType = searchParams.get('productType') ?? undefined;
+    const priority = searchParams.get('priority') ?? undefined;
+    const branch = searchParams.get('branch') ?? undefined;
+    const customer = searchParams.get('customer') ?? undefined;
+    const sort = searchParams.get('sort') ?? undefined;
+    const result = await listEnquiries(organization.id, {
+      page,
+      limit,
+      search,
+      status,
+      productType,
+      priority,
+      branch,
+      customer,
+      sort
+    });
+    const offset = (page - 1) * limit;
+
+    return NextResponse.json({
+      success: true,
+      time: new Date().toISOString(),
+      message: 'Enquiries loaded successfully',
+      totalItems: result.totalItems,
+      offset,
+      limit,
+      items: result.items
+    });
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to load enquiries' }, { status: 500 });
+  }
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const { organization, session } = await requireOrganizationAccess({
+      permission: PERMISSIONS.crmEnquiryCreate
+    });
+    const payload = enquiryRequestSchema.parse(await request.json());
+    const created = await createEnquiry(organization.id, session.user.id, payload);
+
+    await auditCreate({
+      organizationId: organization.id,
+      branchId: created.branchId,
+      userId: session.user.id,
+      entityType: 'crm_enquiry',
+      entityId: created.id,
+      afterData: created
+    });
+
+    return NextResponse.json(
+      {
+        success: true,
+        message: 'Enquiry created successfully',
+        enquiry: created
+      },
+      { status: 201 }
+    );
+  } catch (error) {
+    if (error instanceof AuthError) {
+      return NextResponse.json({ message: error.message }, { status: error.status });
+    }
+
+    if (error instanceof z.ZodError) {
+      return NextResponse.json(
+        { message: error.issues[0]?.message ?? 'Invalid payload' },
+        { status: 400 }
+      );
+    }
+
+    if (error instanceof Error) {
+      return NextResponse.json({ message: error.message }, { status: 400 });
+    }
+
+    return NextResponse.json({ message: 'Unable to create enquiry' }, { status: 500 });
+  }
+}
diff --git a/src/app/dashboard/crm/customers/[id]/page.tsx b/src/app/dashboard/crm/customers/[id]/page.tsx
index 0c4cdef..9f9c996 100644
--- a/src/app/dashboard/crm/customers/[id]/page.tsx
+++ b/src/app/dashboard/crm/customers/[id]/page.tsx
@@ -4,6 +4,7 @@ import PageContainer from '@/components/layout/page-container';
 import { CustomerDetail } from '@/features/crm/customers/components/customer-detail';
 import { customerByIdOptions, customerContactsOptions } from '@/features/crm/customers/api/queries';
 import { getCustomerReferenceData } from '@/features/crm/customers/server/service';
+import { listCustomerEnquiryRelations } from '@/features/crm/enquiries/server/service';
 import { PERMISSIONS } from '@/lib/auth/rbac';
 import { getQueryClient } from '@/lib/query-client';
 
@@ -50,6 +51,10 @@ export default async function CustomerDetailRoute({ params }: PageProps) {
     canRead && session?.user?.activeOrganizationId
       ? await getCustomerReferenceData(session.user.activeOrganizationId)
       : null;
+  const relatedEnquiries =
+    canRead && session?.user?.activeOrganizationId
+      ? await listCustomerEnquiryRelations(id, session.user.activeOrganizationId)
+      : [];
 
   return (
     <PageContainer
@@ -73,6 +78,7 @@ export default async function CustomerDetailRoute({ params }: PageProps) {
               update: canContactUpdate,
               delete: canContactDelete
             }}
+            relatedEnquiries={relatedEnquiries}
           />
         </HydrationBoundary>
       ) : null}
diff --git a/src/app/dashboard/crm/enquiries/[id]/page.tsx b/src/app/dashboard/crm/enquiries/[id]/page.tsx
index fa9e30d..afd6a05 100644
--- a/src/app/dashboard/crm/enquiries/[id]/page.tsx
+++ b/src/app/dashboard/crm/enquiries/[id]/page.tsx
@@ -1,5 +1,11 @@
+import { auth } from '@/auth';
+import { HydrationBoundary, dehydrate } from '@tanstack/react-query';
 import PageContainer from '@/components/layout/page-container';
-import { CrmProductionPlaceholder } from '@/features/foundation/components/crm-production-placeholder';
+import { enquiryByIdOptions, enquiryFollowupsOptions } from '@/features/crm/enquiries/api/queries';
+import { EnquiryDetail } from '@/features/crm/enquiries/components/enquiry-detail';
+import { getEnquiryReferenceData } from '@/features/crm/enquiries/server/service';
+import { PERMISSIONS } from '@/lib/auth/rbac';
+import { getQueryClient } from '@/lib/query-client';
 
 type PageProps = {
   params: Promise<{ id: string }>;
@@ -7,24 +13,69 @@ type PageProps = {
 
 export default async function EnquiryDetailRoute({ params }: PageProps) {
   const { id } = await params;
+  const session = await auth();
+  const canRead =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryRead)));
+  const canUpdate =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryUpdate)));
+  const canFollowupCreate =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryFollowupCreate)));
+  const canFollowupUpdate =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryFollowupUpdate)));
+  const canFollowupDelete =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryFollowupDelete)));
+  const queryClient = getQueryClient();
+
+  if (canRead) {
+    void queryClient.prefetchQuery(enquiryByIdOptions(id));
+    void queryClient.prefetchQuery(enquiryFollowupsOptions(id));
+  }
+
+  const referenceData =
+    canRead && session?.user?.activeOrganizationId
+      ? await getEnquiryReferenceData(session.user.activeOrganizationId)
+      : null;
 
   return (
     <PageContainer
       pageTitle='Enquiry Detail'
-      pageDescription={`Production detail route placeholder for enquiry ${id}.`}
+      pageDescription='Opportunity context, follow-up timeline, and future quotation handoff.'
+      access={canRead}
+      accessFallback={
+        <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center'>
+          You do not have access to this enquiry.
+        </div>
+      }
     >
-      <CrmProductionPlaceholder
-        title='Enquiry detail pending'
-        summary='This route is reserved for the production enquiry detail page and no longer imports the demo in-memory service.'
-        foundationItems={[
-          'Organization context',
-          'Branch validation',
-          'Master option lookups',
-          'Audit logging'
-        ]}
-        nextStep='Implement enquiry detail on top of persisted enquiry, activity, and relationship data.'
-        demoHref={`/dashboard/crm-demo/enquiries/${id}`}
-      />
+      {referenceData ? (
+        <HydrationBoundary state={dehydrate(queryClient)}>
+          <EnquiryDetail
+            enquiryId={id}
+            referenceData={referenceData}
+            canUpdate={canUpdate}
+            canManageFollowups={{
+              create: canFollowupCreate,
+              update: canFollowupUpdate,
+              delete: canFollowupDelete
+            }}
+          />
+        </HydrationBoundary>
+      ) : null}
     </PageContainer>
   );
 }
diff --git a/src/app/dashboard/crm/enquiries/page.tsx b/src/app/dashboard/crm/enquiries/page.tsx
index e9ff830..7dff8e4 100644
--- a/src/app/dashboard/crm/enquiries/page.tsx
+++ b/src/app/dashboard/crm/enquiries/page.tsx
@@ -1,29 +1,70 @@
+import { auth } from '@/auth';
 import PageContainer from '@/components/layout/page-container';
-import { CrmProductionPlaceholder } from '@/features/foundation/components/crm-production-placeholder';
+import EnquiryListing from '@/features/crm/enquiries/components/enquiry-listing';
+import { EnquiryFormSheetTrigger } from '@/features/crm/enquiries/components/enquiry-form-sheet';
+import { getEnquiryReferenceData } from '@/features/crm/enquiries/server/service';
+import { PERMISSIONS } from '@/lib/auth/rbac';
+import { searchParamsCache } from '@/lib/searchparams';
+import type { SearchParams } from 'nuqs/server';
 
 export const metadata = {
   title: 'Dashboard: CRM Enquiries'
 };
 
-export default function EnquiriesRoute() {
+type PageProps = {
+  searchParams: Promise<SearchParams>;
+};
+
+export default async function EnquiriesRoute(props: PageProps) {
+  const searchParams = await props.searchParams;
+  const session = await auth();
+  const canRead =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryRead)));
+  const canCreate =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryCreate)));
+  const canUpdate =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryUpdate)));
+  const canDelete =
+    session?.user?.systemRole === 'super_admin' ||
+    (!!session?.user?.activeOrganizationId &&
+      (session.user.activeMembershipRole === 'admin' ||
+        session.user.activePermissions.includes(PERMISSIONS.crmEnquiryDelete)));
+
+  searchParamsCache.parse(searchParams);
+
+  const referenceData =
+    canRead && session?.user?.activeOrganizationId
+      ? await getEnquiryReferenceData(session.user.activeOrganizationId)
+      : null;
+
   return (
     <PageContainer
       pageTitle='Enquiries'
-      pageDescription='Production enquiry flows are intentionally blocked from mock services until the real module is built.'
+      pageDescription='Production opportunity registry with customer linkage, follow-up workflow, and audit-backed activity.'
+      access={canRead}
+      accessFallback={
+        <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center'>
+          You do not have access to CRM enquiries.
+        </div>
+      }
+      pageHeaderAction={
+        canCreate && referenceData ? (
+          <EnquiryFormSheetTrigger referenceData={referenceData} />
+        ) : null
+      }
     >
-      <CrmProductionPlaceholder
-        title='Enquiry module pending'
-        summary='The demo enquiry workflow remains available only under crm-demo while this production route stays foundation-safe.'
-        foundationItems={[
-          'Master option statuses',
-          'Organization-scoped document sequences',
-          'Branch scope abstraction',
-          'Permission layer',
-          'Audit logging'
-        ]}
-        nextStep='Implement enquiry listing and detail flows on production APIs after Customer and Contact are in place.'
-        demoHref='/dashboard/crm-demo/enquiries'
-      />
+      {referenceData ? (
+        <EnquiryListing referenceData={referenceData} canUpdate={canUpdate} canDelete={canDelete} />
+      ) : null}
     </PageContainer>
   );
 }
diff --git a/src/db/schema.ts b/src/db/schema.ts
index 70fe911..54d1102 100644
--- a/src/db/schema.ts
+++ b/src/db/schema.ts
@@ -188,3 +188,61 @@ export const crmCustomerContacts = pgTable('crm_customer_contacts', {
   createdBy: text('created_by').notNull(),
   updatedBy: text('updated_by').notNull()
 });
+
+export const crmEnquiries = pgTable(
+  'crm_enquiries',
+  {
+    id: text('id').primaryKey(),
+    organizationId: text('organization_id').notNull(),
+    branchId: text('branch_id'),
+    code: text('code').notNull(),
+    customerId: text('customer_id').notNull(),
+    contactId: text('contact_id'),
+    title: text('title').notNull(),
+    description: text('description'),
+    requirement: text('requirement'),
+    projectName: text('project_name'),
+    projectLocation: text('project_location'),
+    productType: text('product_type').notNull(),
+    status: text('status').notNull(),
+    priority: text('priority').notNull(),
+    leadChannel: text('lead_channel'),
+    estimatedValue: doublePrecision('estimated_value'),
+    chancePercent: integer('chance_percent'),
+    expectedCloseDate: timestamp('expected_close_date', { withTimezone: true }),
+    competitor: text('competitor'),
+    source: text('source'),
+    notes: text('notes'),
+    isHotProject: boolean('is_hot_project').default(false).notNull(),
+    isActive: boolean('is_active').default(true).notNull(),
+    createdAt: timestamp('created_at', { withTimezone: true }).defaultNow().notNull(),
+    updatedAt: timestamp('updated_at', { withTimezone: true }).defaultNow().notNull(),
+    deletedAt: timestamp('deleted_at', { withTimezone: true }),
+    createdBy: text('created_by').notNull(),
+    updatedBy: text('updated_by').notNull()
+  },
+  (table) => ({
+    organizationCodeIdx: uniqueIndex('crm_enquiries_org_code_idx').on(
+      table.organizationId,
+      table.code
+    )
+  })
+);
+
+export const crmEnquiryFollowups = pgTable('crm_enquiry_followups', {
+  id: text('id').primaryKey(),
+  organizationId: text('organization_id').notNull(),
+  enquiryId: text('enquiry_id').notNull(),
+  followupDate: timestamp('followup_date', { withTimezone: true }).notNull(),
+  followupType: text('followup_type').notNull(),
+  contactId: text('contact_id'),
+  outcome: text('outcome'),
+  notes: text('notes'),
+  nextFollowupDate: timestamp('next_followup_date', { withTimezone: true }),
+  nextAction: text('next_action'),
+  createdAt: timestamp('created_at', { withTimezone: true }).defaultNow().notNull(),
+  updatedAt: timestamp('updated_at', { withTimezone: true }).defaultNow().notNull(),
+  deletedAt: timestamp('deleted_at', { withTimezone: true }),
+  createdBy: text('created_by').notNull(),
+  updatedBy: text('updated_by').notNull()
+});
diff --git a/src/db/seeds/foundation.seed.ts b/src/db/seeds/foundation.seed.ts
index 0a6fc83..cae1921 100644
--- a/src/db/seeds/foundation.seed.ts
+++ b/src/db/seeds/foundation.seed.ts
@@ -142,6 +142,13 @@ const FOUNDATION_OPTIONS = {
     { code: 'high', label: 'High', value: 'high', sortOrder: 3 },
     { code: 'urgent', label: 'Urgent', value: 'urgent', sortOrder: 4 }
   ],
+  crm_followup_type: [
+    { code: 'call', label: 'Call', value: 'call', sortOrder: 1 },
+    { code: 'meeting', label: 'Meeting', value: 'meeting', sortOrder: 2 },
+    { code: 'site_visit', label: 'Site Visit', value: 'site_visit', sortOrder: 3 },
+    { code: 'email', label: 'Email', value: 'email', sortOrder: 4 },
+    { code: 'line', label: 'LINE', value: 'line', sortOrder: 5 }
+  ],
   crm_lead_channel: [
     { code: 'website', label: 'Website', value: 'website', sortOrder: 1 },
     { code: 'referral', label: 'Referral', value: 'referral', sortOrder: 2 },
diff --git a/src/features/crm/customers/api/types.ts b/src/features/crm/customers/api/types.ts
index b21c6b3..c3819e5 100644
--- a/src/features/crm/customers/api/types.ts
+++ b/src/features/crm/customers/api/types.ts
@@ -77,6 +77,15 @@ export interface CustomerActivityRecord {
   actorName: string | null;
 }
 
+export interface CustomerRelatedEnquiryItem {
+  id: string;
+  code: string;
+  title: string;
+  status: string;
+  productType: string;
+  updatedAt: string;
+}
+
 export interface CustomerReferenceData {
   branches: BranchOption[];
   customerTypes: CustomerOption[];
diff --git a/src/features/crm/customers/components/customer-detail.tsx b/src/features/crm/customers/components/customer-detail.tsx
index f0ae6d2..531c957 100644
--- a/src/features/crm/customers/components/customer-detail.tsx
+++ b/src/features/crm/customers/components/customer-detail.tsx
@@ -14,6 +14,7 @@ import type { CustomerReferenceData } from '../api/types';
 import { CustomerFormSheet } from './customer-form-sheet';
 import { CustomerContactsTab } from './customer-contacts-tab';
 import { CustomerStatusBadge } from './customer-status-badge';
+import type { CustomerRelatedEnquiryItem } from '../api/types';
 
 function FieldItem({ label, value }: { label: string; value: string | null | undefined }) {
   return (
@@ -28,7 +29,8 @@ export function CustomerDetail({
   customerId,
   referenceData,
   canUpdate,
-  canManageContacts
+  canManageContacts,
+  relatedEnquiries
 }: {
   customerId: string;
   referenceData: CustomerReferenceData;
@@ -38,6 +40,7 @@ export function CustomerDetail({
     update: boolean;
     delete: boolean;
   };
+  relatedEnquiries: CustomerRelatedEnquiryItem[];
 }) {
   const { data } = useSuspenseQuery(customerByIdOptions(customerId));
   const [editOpen, setEditOpen] = useState(false);
@@ -212,14 +215,36 @@ export function CustomerDetail({
                     <CardHeader>
                       <CardTitle>Related Documents</CardTitle>
                       <CardDescription>
-                        Task C stops at customer and contact scope, so downstream CRM documents stay
-                        intentionally deferred.
+                        Production enquiry links are now visible here, while quotation and approval
+                        modules stay deferred.
                       </CardDescription>
                     </CardHeader>
                     <CardContent>
-                      <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
-                        Enquiry, quotation, and approval links will land here in Task D and later.
-                      </div>
+                      {!relatedEnquiries.length ? (
+                        <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+                          No enquiries have been linked to this customer yet.
+                        </div>
+                      ) : (
+                        <div className='space-y-3'>
+                          {relatedEnquiries.map((enquiry) => (
+                            <Link
+                              key={enquiry.id}
+                              href={`/dashboard/crm/enquiries/${enquiry.id}`}
+                              className='block rounded-lg border p-4 transition-colors hover:bg-muted/40'
+                            >
+                              <div className='flex items-center justify-between gap-3'>
+                                <div className='space-y-1'>
+                                  <div className='font-medium'>{enquiry.title}</div>
+                                  <div className='text-muted-foreground font-mono text-xs'>
+                                    {enquiry.code}
+                                  </div>
+                                </div>
+                                <Icons.arrowRight className='text-muted-foreground h-4 w-4' />
+                              </div>
+                            </Link>
+                          ))}
+                        </div>
+                      )}
                     </CardContent>
                   </Card>
                 </TabsContent>
diff --git a/src/features/crm/enquiries/api/mutations.ts b/src/features/crm/enquiries/api/mutations.ts
new file mode 100644
index 0000000..5f64a5b
--- /dev/null
+++ b/src/features/crm/enquiries/api/mutations.ts
@@ -0,0 +1,74 @@
+import { mutationOptions } from '@tanstack/react-query';
+import { getQueryClient } from '@/lib/query-client';
+import {
+  createEnquiry,
+  createEnquiryFollowup,
+  deleteEnquiry,
+  deleteEnquiryFollowup,
+  updateEnquiry,
+  updateEnquiryFollowup
+} from './service';
+import { enquiryKeys } from './queries';
+import type { EnquiryFollowupMutationPayload, EnquiryMutationPayload } from './types';
+
+export const createEnquiryMutation = mutationOptions({
+  mutationFn: (data: EnquiryMutationPayload) => createEnquiry(data),
+  onSuccess: () => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.all });
+  }
+});
+
+export const updateEnquiryMutation = mutationOptions({
+  mutationFn: ({ id, values }: { id: string; values: EnquiryMutationPayload }) =>
+    updateEnquiry(id, values),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.all });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.id) });
+  }
+});
+
+export const deleteEnquiryMutation = mutationOptions({
+  mutationFn: (id: string) => deleteEnquiry(id),
+  onSuccess: () => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.all });
+  }
+});
+
+export const createEnquiryFollowupMutation = mutationOptions({
+  mutationFn: ({
+    enquiryId,
+    values
+  }: {
+    enquiryId: string;
+    values: EnquiryFollowupMutationPayload;
+  }) => createEnquiryFollowup(enquiryId, values),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.followups(variables.enquiryId) });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.enquiryId) });
+  }
+});
+
+export const updateEnquiryFollowupMutation = mutationOptions({
+  mutationFn: ({
+    enquiryId,
+    followupId,
+    values
+  }: {
+    enquiryId: string;
+    followupId: string;
+    values: EnquiryFollowupMutationPayload;
+  }) => updateEnquiryFollowup(enquiryId, followupId, values),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.followups(variables.enquiryId) });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.enquiryId) });
+  }
+});
+
+export const deleteEnquiryFollowupMutation = mutationOptions({
+  mutationFn: ({ enquiryId, followupId }: { enquiryId: string; followupId: string }) =>
+    deleteEnquiryFollowup(enquiryId, followupId),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.followups(variables.enquiryId) });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.enquiryId) });
+  }
+});
diff --git a/src/features/crm/enquiries/api/queries.ts b/src/features/crm/enquiries/api/queries.ts
new file mode 100644
index 0000000..47c9e5d
--- /dev/null
+++ b/src/features/crm/enquiries/api/queries.ts
@@ -0,0 +1,28 @@
+import { queryOptions } from '@tanstack/react-query';
+import { getEnquiries, getEnquiryById, getEnquiryFollowups } from './service';
+import type { EnquiryFilters } from './types';
+
+export const enquiryKeys = {
+  all: ['crm-enquiries'] as const,
+  list: (filters: EnquiryFilters) => [...enquiryKeys.all, 'list', filters] as const,
+  detail: (id: string) => [...enquiryKeys.all, 'detail', id] as const,
+  followups: (id: string) => [...enquiryKeys.all, 'followups', id] as const
+};
+
+export const enquiriesQueryOptions = (filters: EnquiryFilters) =>
+  queryOptions({
+    queryKey: enquiryKeys.list(filters),
+    queryFn: () => getEnquiries(filters)
+  });
+
+export const enquiryByIdOptions = (id: string) =>
+  queryOptions({
+    queryKey: enquiryKeys.detail(id),
+    queryFn: () => getEnquiryById(id)
+  });
+
+export const enquiryFollowupsOptions = (id: string) =>
+  queryOptions({
+    queryKey: enquiryKeys.followups(id),
+    queryFn: () => getEnquiryFollowups(id)
+  });
diff --git a/src/features/crm/enquiries/api/service.ts b/src/features/crm/enquiries/api/service.ts
new file mode 100644
index 0000000..4e5c488
--- /dev/null
+++ b/src/features/crm/enquiries/api/service.ts
@@ -0,0 +1,83 @@
+import { apiClient } from '@/lib/api-client';
+import type {
+  EnquiryDetailResponse,
+  EnquiryFilters,
+  EnquiryFollowupMutationPayload,
+  EnquiryFollowupsResponse,
+  EnquiryListResponse,
+  EnquiryMutationPayload,
+  MutationSuccessResponse
+} from './types';
+
+export async function getEnquiries(filters: EnquiryFilters): Promise<EnquiryListResponse> {
+  const searchParams = new URLSearchParams();
+
+  if (filters.page) searchParams.set('page', String(filters.page));
+  if (filters.limit) searchParams.set('limit', String(filters.limit));
+  if (filters.search) searchParams.set('search', filters.search);
+  if (filters.status) searchParams.set('status', filters.status);
+  if (filters.productType) searchParams.set('productType', filters.productType);
+  if (filters.priority) searchParams.set('priority', filters.priority);
+  if (filters.branch) searchParams.set('branch', filters.branch);
+  if (filters.customer) searchParams.set('customer', filters.customer);
+  if (filters.sort) searchParams.set('sort', filters.sort);
+
+  const query = searchParams.toString();
+
+  return apiClient<EnquiryListResponse>(`/crm/enquiries${query ? `?${query}` : ''}`);
+}
+
+export async function getEnquiryById(id: string): Promise<EnquiryDetailResponse> {
+  return apiClient<EnquiryDetailResponse>(`/crm/enquiries/${id}`);
+}
+
+export async function createEnquiry(data: EnquiryMutationPayload) {
+  return apiClient<MutationSuccessResponse>('/crm/enquiries', {
+    method: 'POST',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function updateEnquiry(id: string, data: EnquiryMutationPayload) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${id}`, {
+    method: 'PATCH',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function deleteEnquiry(id: string) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${id}`, {
+    method: 'DELETE'
+  });
+}
+
+export async function getEnquiryFollowups(id: string): Promise<EnquiryFollowupsResponse> {
+  return apiClient<EnquiryFollowupsResponse>(`/crm/enquiries/${id}/followups`);
+}
+
+export async function createEnquiryFollowup(
+  enquiryId: string,
+  data: EnquiryFollowupMutationPayload
+) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${enquiryId}/followups`, {
+    method: 'POST',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function updateEnquiryFollowup(
+  enquiryId: string,
+  followupId: string,
+  data: EnquiryFollowupMutationPayload
+) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${enquiryId}/followups/${followupId}`, {
+    method: 'PATCH',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function deleteEnquiryFollowup(enquiryId: string, followupId: string) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${enquiryId}/followups/${followupId}`, {
+    method: 'DELETE'
+  });
+}
diff --git a/src/features/crm/enquiries/api/types.ts b/src/features/crm/enquiries/api/types.ts
new file mode 100644
index 0000000..2a54c84
--- /dev/null
+++ b/src/features/crm/enquiries/api/types.ts
@@ -0,0 +1,189 @@
+export interface EnquiryOption {
+  id: string;
+  code: string;
+  label: string;
+  value: string | null;
+}
+
+export interface EnquiryBranchOption {
+  id: string;
+  code: string;
+  name: string;
+  value: string | null;
+}
+
+export interface EnquiryCustomerLookup {
+  id: string;
+  code: string;
+  name: string;
+  branchId: string | null;
+}
+
+export interface EnquiryContactLookup {
+  id: string;
+  customerId: string;
+  name: string;
+  email: string | null;
+  mobile: string | null;
+  isPrimary: boolean;
+}
+
+export interface EnquiryRecord {
+  id: string;
+  organizationId: string;
+  branchId: string | null;
+  code: string;
+  customerId: string;
+  contactId: string | null;
+  title: string;
+  description: string | null;
+  requirement: string | null;
+  projectName: string | null;
+  projectLocation: string | null;
+  productType: string;
+  status: string;
+  priority: string;
+  leadChannel: string | null;
+  estimatedValue: number | null;
+  chancePercent: number | null;
+  expectedCloseDate: string | null;
+  competitor: string | null;
+  source: string | null;
+  notes: string | null;
+  isHotProject: boolean;
+  isActive: boolean;
+  createdAt: string;
+  updatedAt: string;
+  deletedAt: string | null;
+  createdBy: string;
+  updatedBy: string;
+}
+
+export interface EnquiryListItem extends EnquiryRecord {
+  customerName: string;
+  contactName: string | null;
+  followupCount: number;
+}
+
+export interface EnquiryFollowupRecord {
+  id: string;
+  organizationId: string;
+  enquiryId: string;
+  followupDate: string;
+  followupType: string;
+  contactId: string | null;
+  outcome: string | null;
+  notes: string | null;
+  nextFollowupDate: string | null;
+  nextAction: string | null;
+  createdAt: string;
+  updatedAt: string;
+  deletedAt: string | null;
+  createdBy: string;
+  updatedBy: string;
+}
+
+export interface EnquiryActivityRecord {
+  id: string;
+  action: string;
+  entityType: string;
+  entityId: string;
+  createdAt: string;
+  userId: string;
+  actorName: string | null;
+}
+
+export interface EnquiryReferenceData {
+  branches: EnquiryBranchOption[];
+  statuses: EnquiryOption[];
+  productTypes: EnquiryOption[];
+  priorities: EnquiryOption[];
+  leadChannels: EnquiryOption[];
+  followupTypes: EnquiryOption[];
+  customers: EnquiryCustomerLookup[];
+  contacts: EnquiryContactLookup[];
+}
+
+export interface EnquiryFilters {
+  page?: number;
+  limit?: number;
+  search?: string;
+  status?: string;
+  productType?: string;
+  priority?: string;
+  branch?: string;
+  customer?: string;
+  sort?: string;
+}
+
+export interface EnquiryListResponse {
+  success: boolean;
+  time: string;
+  message: string;
+  totalItems: number;
+  offset: number;
+  limit: number;
+  items: EnquiryListItem[];
+}
+
+export interface EnquiryDetailResponse {
+  success: boolean;
+  time: string;
+  message: string;
+  enquiry: EnquiryRecord;
+  activity: EnquiryActivityRecord[];
+}
+
+export interface EnquiryFollowupsResponse {
+  success: boolean;
+  time: string;
+  message: string;
+  items: EnquiryFollowupRecord[];
+}
+
+export interface EnquiryMutationPayload {
+  customerId: string;
+  contactId?: string | null;
+  title: string;
+  description?: string;
+  requirement?: string;
+  projectName?: string;
+  projectLocation?: string;
+  branchId?: string | null;
+  productType: string;
+  status: string;
+  priority: string;
+  leadChannel?: string | null;
+  estimatedValue?: number | null;
+  chancePercent?: number | null;
+  expectedCloseDate?: string | null;
+  competitor?: string;
+  source?: string;
+  isHotProject?: boolean;
+  notes?: string;
+  isActive?: boolean;
+}
+
+export interface EnquiryFollowupMutationPayload {
+  followupDate: string;
+  followupType: string;
+  contactId?: string | null;
+  outcome?: string;
+  notes?: string;
+  nextFollowupDate?: string | null;
+  nextAction?: string;
+}
+
+export interface EnquiryCustomerRelationItem {
+  id: string;
+  code: string;
+  title: string;
+  status: string;
+  productType: string;
+  updatedAt: string;
+}
+
+export interface MutationSuccessResponse {
+  success: boolean;
+  message: string;
+}
diff --git a/src/features/crm/enquiries/components/enquiries-table.tsx b/src/features/crm/enquiries/components/enquiries-table.tsx
new file mode 100644
index 0000000..4bf7a45
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiries-table.tsx
@@ -0,0 +1,70 @@
+'use client';
+
+import { useMemo } from 'react';
+import { parseAsInteger, parseAsString, useQueryStates } from 'nuqs';
+import { useSuspenseQuery } from '@tanstack/react-query';
+import { DataTable } from '@/components/ui/table/data-table';
+import { DataTableToolbar } from '@/components/ui/table/data-table-toolbar';
+import { useDataTable } from '@/hooks/use-data-table';
+import { getSortingStateParser } from '@/lib/parsers';
+import { enquiriesQueryOptions } from '../api/queries';
+import type { EnquiryReferenceData } from '../api/types';
+import { getEnquiryColumns } from './enquiry-columns';
+
+export function EnquiriesTable({
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const columns = useMemo(
+    () => getEnquiryColumns({ referenceData, canUpdate, canDelete }),
+    [referenceData, canUpdate, canDelete]
+  );
+  const columnIds = columns.map((column) => column.id).filter(Boolean) as string[];
+  const [params] = useQueryStates({
+    page: parseAsInteger.withDefault(1),
+    perPage: parseAsInteger.withDefault(10),
+    name: parseAsString,
+    status: parseAsString,
+    productType: parseAsString,
+    priority: parseAsString,
+    branch: parseAsString,
+    customer: parseAsString,
+    sort: getSortingStateParser(columnIds).withDefault([])
+  });
+
+  const filters = {
+    page: params.page,
+    limit: params.perPage,
+    ...(params.name && { search: params.name }),
+    ...(params.status && { status: params.status }),
+    ...(params.productType && { productType: params.productType }),
+    ...(params.priority && { priority: params.priority }),
+    ...(params.branch && { branch: params.branch }),
+    ...(params.customer && { customer: params.customer }),
+    ...(params.sort.length > 0 && { sort: JSON.stringify(params.sort) })
+  };
+
+  const { data } = useSuspenseQuery(enquiriesQueryOptions(filters));
+  const pageCount = Math.ceil(data.totalItems / params.perPage);
+  const { table } = useDataTable({
+    data: data.items,
+    columns,
+    pageCount,
+    shallow: true,
+    debounceMs: 500,
+    initialState: {
+      columnPinning: { right: ['actions'] }
+    }
+  });
+
+  return (
+    <DataTable table={table}>
+      <DataTableToolbar table={table} />
+    </DataTable>
+  );
+}
diff --git a/src/features/crm/enquiries/components/enquiry-cell-action.tsx b/src/features/crm/enquiries/components/enquiry-cell-action.tsx
new file mode 100644
index 0000000..4c4c17a
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-cell-action.tsx
@@ -0,0 +1,82 @@
+'use client';
+
+import { useState } from 'react';
+import { useRouter } from 'next/navigation';
+import { useMutation } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { AlertModal } from '@/components/modal/alert-modal';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuLabel,
+  DropdownMenuTrigger
+} from '@/components/ui/dropdown-menu';
+import { deleteEnquiryMutation } from '../api/mutations';
+import type { EnquiryListItem, EnquiryReferenceData } from '../api/types';
+import { EnquiryFormSheet } from './enquiry-form-sheet';
+
+export function EnquiryCellAction({
+  data,
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  data: EnquiryListItem;
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const router = useRouter();
+  const [deleteOpen, setDeleteOpen] = useState(false);
+  const [editOpen, setEditOpen] = useState(false);
+
+  const deleteMutation = useMutation({
+    ...deleteEnquiryMutation,
+    onSuccess: () => {
+      toast.success('Enquiry deleted successfully');
+      setDeleteOpen(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to delete enquiry')
+  });
+
+  return (
+    <>
+      <AlertModal
+        isOpen={deleteOpen}
+        onClose={() => setDeleteOpen(false)}
+        onConfirm={() => deleteMutation.mutate(data.id)}
+        loading={deleteMutation.isPending}
+      />
+      <EnquiryFormSheet
+        enquiry={data}
+        open={editOpen}
+        onOpenChange={setEditOpen}
+        referenceData={referenceData}
+      />
+      <DropdownMenu modal={false}>
+        <DropdownMenuTrigger asChild>
+          <Button variant='ghost' className='h-8 w-8 p-0'>
+            <span className='sr-only'>Open actions</span>
+            <Icons.ellipsis className='h-4 w-4' />
+          </Button>
+        </DropdownMenuTrigger>
+        <DropdownMenuContent align='end'>
+          <DropdownMenuLabel>Actions</DropdownMenuLabel>
+          <DropdownMenuItem onClick={() => router.push(`/dashboard/crm/enquiries/${data.id}`)}>
+            <Icons.arrowRight className='mr-2 h-4 w-4' /> View
+          </DropdownMenuItem>
+          <DropdownMenuItem onClick={() => setEditOpen(true)} disabled={!canUpdate}>
+            <Icons.edit className='mr-2 h-4 w-4' /> Edit
+          </DropdownMenuItem>
+          <DropdownMenuItem onClick={() => setDeleteOpen(true)} disabled={!canDelete}>
+            <Icons.trash className='mr-2 h-4 w-4' /> Delete
+          </DropdownMenuItem>
+        </DropdownMenuContent>
+      </DropdownMenu>
+    </>
+  );
+}
diff --git a/src/features/crm/enquiries/components/enquiry-columns.tsx b/src/features/crm/enquiries/components/enquiry-columns.tsx
new file mode 100644
index 0000000..56caf02
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-columns.tsx
@@ -0,0 +1,176 @@
+'use client';
+
+import Link from 'next/link';
+import type { Column, ColumnDef } from '@tanstack/react-table';
+import { Badge } from '@/components/ui/badge';
+import { DataTableColumnHeader } from '@/components/ui/table/data-table-column-header';
+import { Icons } from '@/components/icons';
+import type { EnquiryListItem, EnquiryReferenceData } from '../api/types';
+import { EnquiryCellAction } from './enquiry-cell-action';
+import { EnquiryStatusBadge } from './enquiry-status-badge';
+
+export function getEnquiryColumns({
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}): ColumnDef<EnquiryListItem>[] {
+  const statusMap = new Map(referenceData.statuses.map((item) => [item.id, item]));
+  const productTypeMap = new Map(referenceData.productTypes.map((item) => [item.id, item]));
+  const priorityMap = new Map(referenceData.priorities.map((item) => [item.id, item]));
+  const branchMap = new Map(referenceData.branches.map((item) => [item.id, item]));
+
+  return [
+    {
+      id: 'title',
+      accessorKey: 'title',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Enquiry' />
+      ),
+      cell: ({ row }) => (
+        <div className='flex flex-col'>
+          <Link
+            href={`/dashboard/crm/enquiries/${row.original.id}`}
+            className='font-medium hover:underline'
+          >
+            {row.original.title}
+          </Link>
+          <span className='text-muted-foreground text-xs'>
+            {row.original.code} • {row.original.customerName}
+          </span>
+        </div>
+      ),
+      meta: {
+        label: 'Enquiry',
+        placeholder: 'Search enquiries...',
+        variant: 'text' as const,
+        icon: Icons.search
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'status',
+      accessorKey: 'status',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Status' />
+      ),
+      cell: ({ row }) => {
+        const status = statusMap.get(row.original.status);
+        return <EnquiryStatusBadge code={status?.code} label={status?.label ?? 'Unknown'} />;
+      },
+      meta: {
+        label: 'Status',
+        variant: 'multiSelect' as const,
+        options: referenceData.statuses.map((item) => ({
+          value: item.id,
+          label: item.label
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'productType',
+      accessorKey: 'productType',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Product Type' />
+      ),
+      cell: ({ row }) => (
+        <Badge variant='outline'>
+          {productTypeMap.get(row.original.productType)?.label ?? 'Unknown'}
+        </Badge>
+      ),
+      meta: {
+        label: 'Product Type',
+        variant: 'multiSelect' as const,
+        options: referenceData.productTypes.map((item) => ({
+          value: item.id,
+          label: item.label
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'priority',
+      accessorKey: 'priority',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Priority' />
+      ),
+      cell: ({ row }) => (
+        <Badge variant='secondary'>
+          {priorityMap.get(row.original.priority)?.label ?? 'Unknown'}
+        </Badge>
+      ),
+      meta: {
+        label: 'Priority',
+        variant: 'multiSelect' as const,
+        options: referenceData.priorities.map((item) => ({
+          value: item.id,
+          label: item.label
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'branch',
+      accessorFn: (row) => row.branchId ?? '',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Branch' />
+      ),
+      cell: ({ row }) => (
+        <span>
+          {row.original.branchId
+            ? (branchMap.get(row.original.branchId)?.name ?? 'Unknown')
+            : 'Unassigned'}
+        </span>
+      ),
+      meta: {
+        label: 'Branch',
+        variant: 'multiSelect' as const,
+        options: referenceData.branches.map((item) => ({
+          value: item.id,
+          label: item.name
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'customer',
+      accessorFn: (row) => row.customerId,
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Customer' />
+      ),
+      cell: ({ row }) => <span>{row.original.customerName}</span>,
+      meta: {
+        label: 'Customer',
+        variant: 'multiSelect' as const,
+        options: referenceData.customers.map((item) => ({
+          value: item.id,
+          label: item.name
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'followupCount',
+      accessorKey: 'followupCount',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Follow-ups' />
+      ),
+      cell: ({ row }) => <span>{row.original.followupCount}</span>
+    },
+    {
+      id: 'actions',
+      cell: ({ row }) => (
+        <EnquiryCellAction
+          data={row.original}
+          referenceData={referenceData}
+          canUpdate={canUpdate}
+          canDelete={canDelete}
+        />
+      )
+    }
+  ];
+}
diff --git a/src/features/crm/enquiries/components/enquiry-detail.tsx b/src/features/crm/enquiries/components/enquiry-detail.tsx
new file mode 100644
index 0000000..da3a500
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-detail.tsx
@@ -0,0 +1,288 @@
+'use client';
+
+import Link from 'next/link';
+import { useMemo, useState } from 'react';
+import { useSuspenseQuery } from '@tanstack/react-query';
+import { Icons } from '@/components/icons';
+import { Badge } from '@/components/ui/badge';
+import { Button } from '@/components/ui/button';
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
+import { Separator } from '@/components/ui/separator';
+import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
+import { enquiryByIdOptions } from '../api/queries';
+import type { EnquiryReferenceData } from '../api/types';
+import { EnquiryFormSheet } from './enquiry-form-sheet';
+import { EnquiryFollowupsTab } from './enquiry-followups-tab';
+import { EnquiryStatusBadge } from './enquiry-status-badge';
+
+function FieldItem({ label, value }: { label: string; value: string | null | undefined }) {
+  return (
+    <div className='space-y-1'>
+      <div className='text-muted-foreground text-xs'>{label}</div>
+      <div className='text-sm'>{value || '-'}</div>
+    </div>
+  );
+}
+
+export function EnquiryDetail({
+  enquiryId,
+  referenceData,
+  canUpdate,
+  canManageFollowups
+}: {
+  enquiryId: string;
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canManageFollowups: {
+    create: boolean;
+    update: boolean;
+    delete: boolean;
+  };
+}) {
+  const { data } = useSuspenseQuery(enquiryByIdOptions(enquiryId));
+  const [editOpen, setEditOpen] = useState(false);
+  const enquiry = data.enquiry;
+  const branchMap = useMemo(
+    () => new Map(referenceData.branches.map((item) => [item.id, item.name])),
+    [referenceData]
+  );
+  const customerMap = useMemo(
+    () => new Map(referenceData.customers.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const contactMap = useMemo(
+    () => new Map(referenceData.contacts.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const statusMap = useMemo(
+    () => new Map(referenceData.statuses.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const productTypeMap = useMemo(
+    () => new Map(referenceData.productTypes.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const priorityMap = useMemo(
+    () => new Map(referenceData.priorities.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const leadChannelMap = useMemo(
+    () => new Map(referenceData.leadChannels.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const customer = customerMap.get(enquiry.customerId);
+  const contact = enquiry.contactId ? contactMap.get(enquiry.contactId) : null;
+  const status = statusMap.get(enquiry.status);
+
+  return (
+    <div className='space-y-6'>
+      <div className='flex flex-col gap-4 rounded-xl border p-5 lg:flex-row lg:items-start lg:justify-between'>
+        <div className='space-y-3'>
+          <div className='flex items-center gap-2'>
+            <Button asChild variant='ghost' size='icon'>
+              <Link href='/dashboard/crm/enquiries'>
+                <Icons.chevronLeft className='h-4 w-4' />
+              </Link>
+            </Button>
+            <span className='text-muted-foreground font-mono text-sm'>{enquiry.code}</span>
+            <EnquiryStatusBadge code={status?.code} label={status?.label ?? 'Unknown'} />
+            {enquiry.isHotProject ? <Badge>Hot</Badge> : null}
+          </div>
+          <div>
+            <h2 className='text-2xl font-semibold'>{enquiry.title}</h2>
+            <p className='text-muted-foreground text-sm'>
+              {customer?.name ?? 'Unknown customer'}
+              {contact ? ` • ${contact.name}` : ''}
+            </p>
+          </div>
+        </div>
+        <div className='flex flex-wrap gap-2'>
+          {canUpdate ? (
+            <Button variant='outline' onClick={() => setEditOpen(true)}>
+              <Icons.edit className='mr-2 h-4 w-4' /> Edit Enquiry
+            </Button>
+          ) : null}
+        </div>
+      </div>
+
+      <div className='grid gap-6 lg:grid-cols-3'>
+        <div className='space-y-6 lg:col-span-2'>
+          <Card>
+            <CardContent className='pt-6'>
+              <Tabs defaultValue='overview' className='gap-4'>
+                <TabsList>
+                  <TabsTrigger value='overview'>Overview</TabsTrigger>
+                  <TabsTrigger value='followups'>Follow-ups</TabsTrigger>
+                  <TabsTrigger value='activity'>Activity</TabsTrigger>
+                  <TabsTrigger value='related'>Related Quotations</TabsTrigger>
+                </TabsList>
+                <TabsContent value='overview'>
+                  <Card>
+                    <CardHeader>
+                      <CardTitle>Overview</CardTitle>
+                      <CardDescription>
+                        Opportunity scope, project context, and commercial direction.
+                      </CardDescription>
+                    </CardHeader>
+                    <CardContent className='grid gap-4 md:grid-cols-2 xl:grid-cols-4'>
+                      <FieldItem label='Customer' value={customer?.name} />
+                      <FieldItem label='Contact' value={contact?.name} />
+                      <FieldItem
+                        label='Branch'
+                        value={enquiry.branchId ? branchMap.get(enquiry.branchId) : null}
+                      />
+                      <FieldItem label='Active' value={enquiry.isActive ? 'Yes' : 'No'} />
+                      <FieldItem
+                        label='Product Type'
+                        value={productTypeMap.get(enquiry.productType)?.label}
+                      />
+                      <FieldItem
+                        label='Priority'
+                        value={priorityMap.get(enquiry.priority)?.label}
+                      />
+                      <FieldItem
+                        label='Lead Channel'
+                        value={leadChannelMap.get(enquiry.leadChannel ?? '')?.label}
+                      />
+                      <FieldItem
+                        label='Expected Close Date'
+                        value={
+                          enquiry.expectedCloseDate
+                            ? new Date(enquiry.expectedCloseDate).toLocaleDateString()
+                            : null
+                        }
+                      />
+                      <FieldItem
+                        label='Estimated Value'
+                        value={
+                          enquiry.estimatedValue !== null
+                            ? enquiry.estimatedValue.toLocaleString()
+                            : null
+                        }
+                      />
+                      <FieldItem
+                        label='Chance %'
+                        value={enquiry.chancePercent !== null ? `${enquiry.chancePercent}%` : null}
+                      />
+                      <FieldItem label='Competitor' value={enquiry.competitor} />
+                      <FieldItem label='Source' value={enquiry.source} />
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem
+                          label='Project'
+                          value={
+                            [enquiry.projectName, enquiry.projectLocation]
+                              .filter(Boolean)
+                              .join(' • ') || null
+                          }
+                        />
+                      </div>
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem label='Description' value={enquiry.description} />
+                      </div>
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem label='Requirement' value={enquiry.requirement} />
+                      </div>
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem label='Notes' value={enquiry.notes} />
+                      </div>
+                    </CardContent>
+                  </Card>
+                </TabsContent>
+                <TabsContent value='followups'>
+                  <EnquiryFollowupsTab
+                    enquiryId={enquiryId}
+                    customerId={enquiry.customerId}
+                    referenceData={referenceData}
+                    canCreate={canManageFollowups.create}
+                    canUpdate={canManageFollowups.update}
+                    canDelete={canManageFollowups.delete}
+                  />
+                </TabsContent>
+                <TabsContent value='activity'>
+                  <Card>
+                    <CardHeader>
+                      <CardTitle>Activity</CardTitle>
+                      <CardDescription>
+                        Audit events for the enquiry and its follow-up records.
+                      </CardDescription>
+                    </CardHeader>
+                    <CardContent className='space-y-4'>
+                      {!data.activity.length ? (
+                        <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+                          No activity recorded yet.
+                        </div>
+                      ) : (
+                        data.activity.map((item, index) => (
+                          <div key={item.id} className='space-y-4'>
+                            <div className='flex items-start gap-3'>
+                              <div className='bg-primary mt-2 h-2 w-2 rounded-full' />
+                              <div className='space-y-1'>
+                                <div className='flex items-center gap-2'>
+                                  <Badge variant='outline' className='capitalize'>
+                                    {item.action}
+                                  </Badge>
+                                  <Badge variant='secondary'>
+                                    {item.entityType.replaceAll('_', ' ')}
+                                  </Badge>
+                                  <span className='text-sm font-medium'>
+                                    {item.actorName ?? item.userId}
+                                  </span>
+                                </div>
+                                <div className='text-muted-foreground text-xs'>
+                                  {new Date(item.createdAt).toLocaleString()}
+                                </div>
+                              </div>
+                            </div>
+                            {index < data.activity.length - 1 ? <Separator /> : null}
+                          </div>
+                        ))
+                      )}
+                    </CardContent>
+                  </Card>
+                </TabsContent>
+                <TabsContent value='related'>
+                  <Card>
+                    <CardHeader>
+                      <CardTitle>Related Quotations</CardTitle>
+                      <CardDescription>
+                        Task D ends at enquiry readiness, so quotation production stays
+                        intentionally deferred.
+                      </CardDescription>
+                    </CardHeader>
+                    <CardContent>
+                      <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+                        Quotation linkage will land here in Task E.
+                      </div>
+                    </CardContent>
+                  </Card>
+                </TabsContent>
+              </Tabs>
+            </CardContent>
+          </Card>
+        </div>
+
+        <div className='space-y-6'>
+          <Card>
+            <CardHeader>
+              <CardTitle>Record Snapshot</CardTitle>
+              <CardDescription>Operational metadata for this enquiry row.</CardDescription>
+            </CardHeader>
+            <CardContent className='space-y-4'>
+              <FieldItem label='Created By' value={enquiry.createdBy} />
+              <FieldItem label='Updated By' value={enquiry.updatedBy} />
+              <FieldItem label='Created At' value={new Date(enquiry.createdAt).toLocaleString()} />
+              <FieldItem label='Updated At' value={new Date(enquiry.updatedAt).toLocaleString()} />
+            </CardContent>
+          </Card>
+        </div>
+      </div>
+
+      <EnquiryFormSheet
+        enquiry={enquiry}
+        open={editOpen}
+        onOpenChange={setEditOpen}
+        referenceData={referenceData}
+      />
+    </div>
+  );
+}
diff --git a/src/features/crm/enquiries/components/enquiry-followups-tab.tsx b/src/features/crm/enquiries/components/enquiry-followups-tab.tsx
new file mode 100644
index 0000000..e225cf0
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-followups-tab.tsx
@@ -0,0 +1,150 @@
+'use client';
+
+import { useState } from 'react';
+import { useMutation, useSuspenseQuery } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { AlertModal } from '@/components/modal/alert-modal';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
+import { Badge } from '@/components/ui/badge';
+import { deleteEnquiryFollowupMutation } from '../api/mutations';
+import { enquiryFollowupsOptions } from '../api/queries';
+import type { EnquiryReferenceData } from '../api/types';
+import { FollowupFormSheet } from './followup-form-sheet';
+
+export function EnquiryFollowupsTab({
+  enquiryId,
+  customerId,
+  referenceData,
+  canCreate,
+  canUpdate,
+  canDelete
+}: {
+  enquiryId: string;
+  customerId: string;
+  referenceData: EnquiryReferenceData;
+  canCreate: boolean;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const { data } = useSuspenseQuery(enquiryFollowupsOptions(enquiryId));
+  const [selectedId, setSelectedId] = useState<string | null>(null);
+  const [open, setOpen] = useState(false);
+  const [deleteOpen, setDeleteOpen] = useState(false);
+  const selected = data.items.find((item) => item.id === selectedId);
+  const followupTypeMap = new Map(referenceData.followupTypes.map((item) => [item.id, item.label]));
+
+  const deleteMutation = useMutation({
+    ...deleteEnquiryFollowupMutation,
+    onSuccess: () => {
+      toast.success('Follow-up deleted successfully');
+      setDeleteOpen(false);
+      setSelectedId(null);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to delete follow-up')
+  });
+
+  return (
+    <Card>
+      <CardHeader className='flex flex-row items-start justify-between gap-4'>
+        <div>
+          <CardTitle>Follow-ups</CardTitle>
+          <CardDescription>
+            Track the latest contact moments, outcomes, and next steps for this enquiry.
+          </CardDescription>
+        </div>
+        {canCreate ? (
+          <Button
+            size='sm'
+            onClick={() => {
+              setSelectedId(null);
+              setOpen(true);
+            }}
+          >
+            <Icons.add className='mr-2 h-4 w-4' /> Add Follow-up
+          </Button>
+        ) : null}
+      </CardHeader>
+      <CardContent className='space-y-4'>
+        {!data.items.length ? (
+          <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+            No follow-ups recorded yet.
+          </div>
+        ) : (
+          data.items.map((item) => (
+            <div
+              key={item.id}
+              className='flex flex-col gap-3 rounded-lg border p-4 md:flex-row md:items-start md:justify-between'
+            >
+              <div className='space-y-2'>
+                <div className='flex flex-wrap items-center gap-2'>
+                  <Badge variant='outline'>
+                    {followupTypeMap.get(item.followupType) ?? 'Unknown type'}
+                  </Badge>
+                  <span className='text-sm font-medium'>
+                    {new Date(item.followupDate).toLocaleDateString()}
+                  </span>
+                </div>
+                {item.outcome ? <p className='text-sm'>{item.outcome}</p> : null}
+                {item.nextAction ? (
+                  <p className='text-muted-foreground text-sm'>Next action: {item.nextAction}</p>
+                ) : null}
+                {item.nextFollowupDate ? (
+                  <p className='text-muted-foreground text-sm'>
+                    Next follow-up: {new Date(item.nextFollowupDate).toLocaleDateString()}
+                  </p>
+                ) : null}
+                {item.notes ? <p className='text-muted-foreground text-sm'>{item.notes}</p> : null}
+              </div>
+              <div className='flex gap-2'>
+                <Button
+                  variant='outline'
+                  size='sm'
+                  disabled={!canUpdate}
+                  onClick={() => {
+                    setSelectedId(item.id);
+                    setOpen(true);
+                  }}
+                >
+                  <Icons.edit className='mr-2 h-4 w-4' /> Edit
+                </Button>
+                <Button
+                  variant='outline'
+                  size='sm'
+                  disabled={!canDelete}
+                  onClick={() => {
+                    setSelectedId(item.id);
+                    setDeleteOpen(true);
+                  }}
+                >
+                  <Icons.trash className='mr-2 h-4 w-4' /> Delete
+                </Button>
+              </div>
+            </div>
+          ))
+        )}
+      </CardContent>
+
+      <FollowupFormSheet
+        enquiryId={enquiryId}
+        followup={selected}
+        open={open}
+        onOpenChange={setOpen}
+        referenceData={referenceData}
+        customerId={customerId}
+      />
+      <AlertModal
+        isOpen={deleteOpen}
+        onClose={() => setDeleteOpen(false)}
+        onConfirm={() => {
+          if (selectedId) {
+            deleteMutation.mutate({ enquiryId, followupId: selectedId });
+          }
+        }}
+        loading={deleteMutation.isPending}
+      />
+    </Card>
+  );
+}
diff --git a/src/features/crm/enquiries/components/enquiry-form-sheet.tsx b/src/features/crm/enquiries/components/enquiry-form-sheet.tsx
new file mode 100644
index 0000000..8c776e8
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-form-sheet.tsx
@@ -0,0 +1,377 @@
+'use client';
+
+import * as React from 'react';
+import { useEffect, useMemo, useState } from 'react';
+import { useMutation } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue
+} from '@/components/ui/select';
+import {
+  Sheet,
+  SheetContent,
+  SheetDescription,
+  SheetFooter,
+  SheetHeader,
+  SheetTitle
+} from '@/components/ui/sheet';
+import { useAppForm, useFormFields } from '@/components/ui/tanstack-form';
+import { createEnquiryMutation, updateEnquiryMutation } from '../api/mutations';
+import type { EnquiryMutationPayload, EnquiryRecord, EnquiryReferenceData } from '../api/types';
+import { enquirySchema, type EnquiryFormValues } from '../schemas/enquiry.schema';
+
+function toDefaultValues(
+  enquiry: EnquiryRecord | undefined,
+  referenceData: EnquiryReferenceData
+): EnquiryFormValues {
+  return {
+    customerId: enquiry?.customerId ?? referenceData.customers[0]?.id ?? '',
+    contactId: enquiry?.contactId ?? undefined,
+    title: enquiry?.title ?? '',
+    description: enquiry?.description ?? '',
+    requirement: enquiry?.requirement ?? '',
+    projectName: enquiry?.projectName ?? '',
+    projectLocation: enquiry?.projectLocation ?? '',
+    branchId: enquiry?.branchId ?? undefined,
+    productType: enquiry?.productType ?? referenceData.productTypes[0]?.id ?? '',
+    status: enquiry?.status ?? referenceData.statuses[0]?.id ?? '',
+    priority:
+      enquiry?.priority ?? referenceData.priorities[1]?.id ?? referenceData.priorities[0]?.id ?? '',
+    leadChannel: enquiry?.leadChannel ?? undefined,
+    estimatedValue: enquiry?.estimatedValue ? String(enquiry.estimatedValue) : '',
+    chancePercent:
+      enquiry?.chancePercent !== null && enquiry?.chancePercent !== undefined
+        ? String(enquiry.chancePercent)
+        : '',
+    expectedCloseDate: enquiry?.expectedCloseDate ? enquiry.expectedCloseDate.slice(0, 10) : '',
+    competitor: enquiry?.competitor ?? '',
+    source: enquiry?.source ?? '',
+    isHotProject: enquiry?.isHotProject ?? false,
+    notes: enquiry?.notes ?? '',
+    isActive: enquiry?.isActive ?? true
+  };
+}
+
+export function EnquiryFormSheet({
+  enquiry,
+  open,
+  onOpenChange,
+  referenceData
+}: {
+  enquiry?: EnquiryRecord;
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+  referenceData: EnquiryReferenceData;
+}) {
+  const isEdit = !!enquiry;
+  const defaultValues = useMemo(
+    () => toDefaultValues(enquiry, referenceData),
+    [enquiry, referenceData]
+  );
+  const [selectedCustomerId, setSelectedCustomerId] = useState(defaultValues.customerId);
+  const { FormTextField, FormTextareaField, FormSelectField, FormSwitchField } =
+    useFormFields<EnquiryFormValues>();
+
+  const createMutation = useMutation({
+    ...createEnquiryMutation,
+    onSuccess: () => {
+      toast.success('Enquiry created successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to create enquiry')
+  });
+
+  const updateMutation = useMutation({
+    ...updateEnquiryMutation,
+    onSuccess: () => {
+      toast.success('Enquiry updated successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to update enquiry')
+  });
+
+  const contactsForCustomer = referenceData.contacts.filter(
+    (contact) => contact.customerId === selectedCustomerId
+  );
+
+  const form = useAppForm({
+    defaultValues,
+    validators: {
+      onSubmit: enquirySchema
+    },
+    onSubmit: async ({ value }) => {
+      const payload: EnquiryMutationPayload = {
+        customerId: value.customerId,
+        contactId: value.contactId || null,
+        title: value.title,
+        description: value.description,
+        requirement: value.requirement,
+        projectName: value.projectName,
+        projectLocation: value.projectLocation,
+        branchId: value.branchId || null,
+        productType: value.productType,
+        status: value.status,
+        priority: value.priority,
+        leadChannel: value.leadChannel || null,
+        estimatedValue: value.estimatedValue ? Number(value.estimatedValue) : null,
+        chancePercent: value.chancePercent ? Number(value.chancePercent) : null,
+        expectedCloseDate: value.expectedCloseDate || null,
+        competitor: value.competitor,
+        source: value.source,
+        isHotProject: value.isHotProject ?? false,
+        notes: value.notes,
+        isActive: value.isActive ?? true
+      };
+
+      if (isEdit && enquiry) {
+        await updateMutation.mutateAsync({ id: enquiry.id, values: payload });
+        return;
+      }
+
+      await createMutation.mutateAsync(payload);
+    }
+  });
+
+  useEffect(() => {
+    if (!open) {
+      return;
+    }
+
+    setSelectedCustomerId(defaultValues.customerId);
+    form.reset(defaultValues);
+  }, [defaultValues, form, open]);
+
+  const isPending = createMutation.isPending || updateMutation.isPending;
+
+  return (
+    <Sheet open={open} onOpenChange={onOpenChange}>
+      <SheetContent className='flex flex-col sm:max-w-4xl'>
+        <SheetHeader>
+          <SheetTitle>{isEdit ? 'Edit Enquiry' : 'New Enquiry'}</SheetTitle>
+          <SheetDescription>
+            Capture the opportunity details before quotation and approval stages begin.
+          </SheetDescription>
+        </SheetHeader>
+
+        <div className='flex-1 overflow-auto'>
+          <form.AppForm>
+            <form.Form id='enquiry-form-sheet' className='grid gap-4 md:grid-cols-2'>
+              <form.AppField
+                name='customerId'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Customer *</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value);
+                          field.handleBlur();
+                          setSelectedCustomerId(value);
+                          form.setFieldValue('contactId', '');
+                        }}
+                      >
+                        <SelectTrigger aria-label='Customer'>
+                          <SelectValue placeholder='Select customer' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {referenceData.customers.map((customer) => (
+                            <SelectItem key={customer.id} value={customer.id}>
+                              {customer.name} ({customer.code})
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+
+              <form.AppField
+                name='contactId'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Contact</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value === '__none__' ? '' : value);
+                          field.handleBlur();
+                        }}
+                      >
+                        <SelectTrigger aria-label='Contact'>
+                          <SelectValue placeholder='Select contact' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {contactsForCustomer.length ? (
+                            contactsForCustomer.map((contact) => (
+                              <SelectItem key={contact.id} value={contact.id}>
+                                {contact.name}
+                                {contact.isPrimary ? ' (Primary)' : ''}
+                              </SelectItem>
+                            ))
+                          ) : (
+                            <SelectItem value='__none__'>No contact selected</SelectItem>
+                          )}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+
+              <FormTextField
+                name='title'
+                label='Title'
+                required
+                placeholder='Warehouse crane upgrade opportunity'
+              />
+              <FormTextField
+                name='projectName'
+                label='Project Name'
+                placeholder='Bangna Warehouse Expansion'
+              />
+              <FormTextField
+                name='projectLocation'
+                label='Project Location'
+                placeholder='Bangkok'
+              />
+              <FormTextField
+                name='source'
+                label='Source'
+                placeholder='Existing customer referral'
+              />
+              <FormSelectField
+                name='branchId'
+                label='Branch'
+                options={referenceData.branches.map((branch) => ({
+                  value: branch.id,
+                  label: branch.name
+                }))}
+              />
+              <FormSelectField
+                name='productType'
+                label='Product Type'
+                required
+                options={referenceData.productTypes.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormSelectField
+                name='status'
+                label='Status'
+                required
+                options={referenceData.statuses.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormSelectField
+                name='priority'
+                label='Priority'
+                required
+                options={referenceData.priorities.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormSelectField
+                name='leadChannel'
+                label='Lead Channel'
+                options={referenceData.leadChannels.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormTextField
+                name='estimatedValue'
+                label='Estimated Value'
+                type='number'
+                placeholder='2500000'
+              />
+              <FormTextField name='chancePercent' label='Chance %' type='number' placeholder='60' />
+              <FormTextField
+                name='expectedCloseDate'
+                label='Expected Close Date'
+                placeholder='YYYY-MM-DD'
+              />
+              <FormTextField name='competitor' label='Competitor' placeholder='Other vendor name' />
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='description'
+                  label='Description'
+                  placeholder='High-level summary of the opportunity'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='requirement'
+                  label='Requirement'
+                  placeholder='Specific technical or commercial requirements'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='notes'
+                  label='Notes'
+                  placeholder='Internal notes, blockers, or guidance for the sales team'
+                />
+              </div>
+              <div className='md:col-span-2 grid gap-4 md:grid-cols-2'>
+                <FormSwitchField
+                  name='isHotProject'
+                  label='Hot Project'
+                  description='Use for urgent or highly strategic opportunities.'
+                />
+                <FormSwitchField
+                  name='isActive'
+                  label='Active Record'
+                  description='Inactive enquiries stay in history but should not progress further.'
+                />
+              </div>
+            </form.Form>
+          </form.AppForm>
+        </div>
+
+        <SheetFooter>
+          <Button type='button' variant='outline' onClick={() => onOpenChange(false)}>
+            Cancel
+          </Button>
+          <Button type='submit' form='enquiry-form-sheet' isLoading={isPending}>
+            <Icons.check className='mr-2 h-4 w-4' />
+            {isEdit ? 'Update Enquiry' : 'Create Enquiry'}
+          </Button>
+        </SheetFooter>
+      </SheetContent>
+    </Sheet>
+  );
+}
+
+export function EnquiryFormSheetTrigger({
+  referenceData
+}: {
+  referenceData: EnquiryReferenceData;
+}) {
+  const [open, setOpen] = React.useState(false);
+
+  return (
+    <>
+      <Button onClick={() => setOpen(true)}>
+        <Icons.add className='mr-2 h-4 w-4' /> Add Enquiry
+      </Button>
+      <EnquiryFormSheet open={open} onOpenChange={setOpen} referenceData={referenceData} />
+    </>
+  );
+}
diff --git a/src/features/crm/enquiries/components/enquiry-listing.tsx b/src/features/crm/enquiries/components/enquiry-listing.tsx
new file mode 100644
index 0000000..da1ea38
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-listing.tsx
@@ -0,0 +1,46 @@
+import { HydrationBoundary, dehydrate } from '@tanstack/react-query';
+import { getQueryClient } from '@/lib/query-client';
+import { searchParamsCache } from '@/lib/searchparams';
+import type { EnquiryReferenceData } from '../api/types';
+import { enquiriesQueryOptions } from '../api/queries';
+import { EnquiriesTable } from './enquiries-table';
+
+export default function EnquiryListing({
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const page = searchParamsCache.get('page');
+  const limit = searchParamsCache.get('perPage');
+  const search = searchParamsCache.get('name');
+  const status = searchParamsCache.get('status');
+  const productType = searchParamsCache.get('productType');
+  const priority = searchParamsCache.get('priority');
+  const branch = searchParamsCache.get('branch');
+  const customer = searchParamsCache.get('customer');
+  const sort = searchParamsCache.get('sort');
+  const filters = {
+    page,
+    limit,
+    ...(search && { search }),
+    ...(status && { status }),
+    ...(productType && { productType }),
+    ...(priority && { priority }),
+    ...(branch && { branch }),
+    ...(customer && { customer }),
+    ...(sort && { sort })
+  };
+  const queryClient = getQueryClient();
+
+  void queryClient.prefetchQuery(enquiriesQueryOptions(filters));
+
+  return (
+    <HydrationBoundary state={dehydrate(queryClient)}>
+      <EnquiriesTable referenceData={referenceData} canUpdate={canUpdate} canDelete={canDelete} />
+    </HydrationBoundary>
+  );
+}
diff --git a/src/features/crm/enquiries/components/enquiry-status-badge.tsx b/src/features/crm/enquiries/components/enquiry-status-badge.tsx
new file mode 100644
index 0000000..1558f7b
--- /dev/null
+++ b/src/features/crm/enquiries/components/enquiry-status-badge.tsx
@@ -0,0 +1,31 @@
+'use client';
+
+import { Badge } from '@/components/ui/badge';
+import { Icons } from '@/components/icons';
+
+export function EnquiryStatusBadge({ code, label }: { code?: string | null; label: string }) {
+  const normalized = code?.toLowerCase() ?? '';
+  const variant =
+    normalized === 'closed_lost' || normalized === 'cancelled'
+      ? 'outline'
+      : normalized === 'converted'
+        ? 'default'
+        : normalized === 'follow_up'
+          ? 'secondary'
+          : 'secondary';
+  const Icon =
+    normalized === 'converted'
+      ? Icons.circleCheck
+      : normalized === 'closed_lost' || normalized === 'cancelled'
+        ? Icons.warning
+        : normalized === 'follow_up'
+          ? Icons.clock
+          : Icons.circle;
+
+  return (
+    <Badge variant={variant} className='capitalize'>
+      <Icon className='h-3 w-3' />
+      {label}
+    </Badge>
+  );
+}
diff --git a/src/features/crm/enquiries/components/followup-form-sheet.tsx b/src/features/crm/enquiries/components/followup-form-sheet.tsx
new file mode 100644
index 0000000..d8f6816
--- /dev/null
+++ b/src/features/crm/enquiries/components/followup-form-sheet.tsx
@@ -0,0 +1,249 @@
+'use client';
+
+import { useEffect, useMemo } from 'react';
+import { useMutation } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue
+} from '@/components/ui/select';
+import {
+  Sheet,
+  SheetContent,
+  SheetDescription,
+  SheetFooter,
+  SheetHeader,
+  SheetTitle
+} from '@/components/ui/sheet';
+import { useAppForm, useFormFields } from '@/components/ui/tanstack-form';
+import { createEnquiryFollowupMutation, updateEnquiryFollowupMutation } from '../api/mutations';
+import type {
+  EnquiryFollowupMutationPayload,
+  EnquiryFollowupRecord,
+  EnquiryReferenceData
+} from '../api/types';
+import { enquiryFollowupSchema, type EnquiryFollowupFormValues } from '../schemas/enquiry.schema';
+
+function toDefaultValues(followup: EnquiryFollowupRecord | undefined): EnquiryFollowupFormValues {
+  return {
+    followupDate: followup?.followupDate ? followup.followupDate.slice(0, 10) : '',
+    followupType: followup?.followupType ?? '',
+    contactId: followup?.contactId ?? undefined,
+    outcome: followup?.outcome ?? '',
+    notes: followup?.notes ?? '',
+    nextFollowupDate: followup?.nextFollowupDate ? followup.nextFollowupDate.slice(0, 10) : '',
+    nextAction: followup?.nextAction ?? ''
+  };
+}
+
+export function FollowupFormSheet({
+  enquiryId,
+  followup,
+  open,
+  onOpenChange,
+  referenceData,
+  customerId
+}: {
+  enquiryId: string;
+  followup?: EnquiryFollowupRecord;
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+  referenceData: EnquiryReferenceData;
+  customerId: string;
+}) {
+  const isEdit = !!followup;
+  const defaultValues = useMemo(() => toDefaultValues(followup), [followup]);
+  const { FormTextField, FormTextareaField } = useFormFields<EnquiryFollowupFormValues>();
+  const contactOptions = referenceData.contacts.filter((item) => item.customerId === customerId);
+
+  const createMutation = useMutation({
+    ...createEnquiryFollowupMutation,
+    onSuccess: () => {
+      toast.success('Follow-up created successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to create follow-up')
+  });
+
+  const updateMutation = useMutation({
+    ...updateEnquiryFollowupMutation,
+    onSuccess: () => {
+      toast.success('Follow-up updated successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to update follow-up')
+  });
+
+  const form = useAppForm({
+    defaultValues,
+    validators: {
+      onSubmit: enquiryFollowupSchema
+    },
+    onSubmit: async ({ value }) => {
+      const payload: EnquiryFollowupMutationPayload = {
+        followupDate: value.followupDate,
+        followupType: value.followupType,
+        contactId: value.contactId || null,
+        outcome: value.outcome,
+        notes: value.notes,
+        nextFollowupDate: value.nextFollowupDate || null,
+        nextAction: value.nextAction
+      };
+
+      if (isEdit && followup) {
+        await updateMutation.mutateAsync({
+          enquiryId,
+          followupId: followup.id,
+          values: payload
+        });
+        return;
+      }
+
+      await createMutation.mutateAsync({
+        enquiryId,
+        values: payload
+      });
+    }
+  });
+
+  useEffect(() => {
+    if (!open) {
+      return;
+    }
+
+    form.reset(defaultValues);
+  }, [defaultValues, form, open]);
+
+  const isPending = createMutation.isPending || updateMutation.isPending;
+
+  return (
+    <Sheet open={open} onOpenChange={onOpenChange}>
+      <SheetContent className='flex flex-col sm:max-w-2xl'>
+        <SheetHeader>
+          <SheetTitle>{isEdit ? 'Edit Follow-up' : 'New Follow-up'}</SheetTitle>
+          <SheetDescription>
+            Keep the enquiry timeline current with the latest customer interaction and next step.
+          </SheetDescription>
+        </SheetHeader>
+
+        <div className='flex-1 overflow-auto'>
+          <form.AppForm>
+            <form.Form id='enquiry-followup-form' className='grid gap-4 md:grid-cols-2'>
+              <FormTextField
+                name='followupDate'
+                label='Follow-up Date'
+                required
+                placeholder='YYYY-MM-DD'
+              />
+              <form.AppField
+                name='followupType'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Follow-up Type *</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value === '__none__' ? '' : value);
+                          field.handleBlur();
+                        }}
+                      >
+                        <SelectTrigger aria-label='Follow-up type'>
+                          <SelectValue placeholder='Select follow-up type' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {referenceData.followupTypes.map((item) => (
+                            <SelectItem key={item.id} value={item.id}>
+                              {item.label}
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+              <form.AppField
+                name='contactId'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Contact</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value);
+                          field.handleBlur();
+                        }}
+                      >
+                        <SelectTrigger aria-label='Follow-up contact'>
+                          <SelectValue placeholder='Select contact' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {contactOptions.length ? (
+                            contactOptions.map((item) => (
+                              <SelectItem key={item.id} value={item.id}>
+                                {item.name}
+                              </SelectItem>
+                            ))
+                          ) : (
+                            <SelectItem value='__none__'>No contact selected</SelectItem>
+                          )}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+              <FormTextField
+                name='nextFollowupDate'
+                label='Next Follow-up Date'
+                placeholder='YYYY-MM-DD'
+              />
+              <div className='md:col-span-2'>
+                <FormTextField
+                  name='nextAction'
+                  label='Next Action'
+                  placeholder='Prepare revised technical proposal'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='outcome'
+                  label='Outcome'
+                  placeholder='Customer asked for revised dimensions and a site survey'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='notes'
+                  label='Notes'
+                  placeholder='Internal notes from the follow-up session'
+                />
+              </div>
+            </form.Form>
+          </form.AppForm>
+        </div>
+
+        <SheetFooter>
+          <Button type='button' variant='outline' onClick={() => onOpenChange(false)}>
+            Cancel
+          </Button>
+          <Button type='submit' form='enquiry-followup-form' isLoading={isPending}>
+            <Icons.check className='mr-2 h-4 w-4' />
+            {isEdit ? 'Update Follow-up' : 'Create Follow-up'}
+          </Button>
+        </SheetFooter>
+      </SheetContent>
+    </Sheet>
+  );
+}
diff --git a/src/features/crm/enquiries/schemas/enquiry.schema.ts b/src/features/crm/enquiries/schemas/enquiry.schema.ts
new file mode 100644
index 0000000..05c7419
--- /dev/null
+++ b/src/features/crm/enquiries/schemas/enquiry.schema.ts
@@ -0,0 +1,47 @@
+import * as z from 'zod';
+
+export const enquirySchema = z.object({
+  customerId: z.string().min(1, 'Please select a customer'),
+  contactId: z.string().optional().nullable(),
+  title: z.string().min(2, 'Title must be at least 2 characters'),
+  description: z.string().optional(),
+  requirement: z.string().optional(),
+  projectName: z.string().optional(),
+  projectLocation: z.string().optional(),
+  branchId: z.string().optional().nullable(),
+  productType: z.string().min(1, 'Please select a product type'),
+  status: z.string().min(1, 'Please select a status'),
+  priority: z.string().min(1, 'Please select a priority'),
+  leadChannel: z.string().optional().nullable(),
+  estimatedValue: z
+    .string()
+    .optional()
+    .refine((value) => !value || !Number.isNaN(Number(value)), 'Estimated value must be a number'),
+  chancePercent: z
+    .string()
+    .optional()
+    .refine((value) => !value || !Number.isNaN(Number(value)), 'Chance percent must be a number')
+    .refine(
+      (value) => !value || (Number(value) >= 0 && Number(value) <= 100),
+      'Chance percent must be between 0 and 100'
+    ),
+  expectedCloseDate: z.string().optional().nullable(),
+  competitor: z.string().optional(),
+  source: z.string().optional(),
+  isHotProject: z.boolean().default(false),
+  notes: z.string().optional(),
+  isActive: z.boolean().default(true)
+});
+
+export const enquiryFollowupSchema = z.object({
+  followupDate: z.string().min(1, 'Follow-up date is required'),
+  followupType: z.string().min(1, 'Please select a follow-up type'),
+  contactId: z.string().optional().nullable(),
+  outcome: z.string().optional(),
+  notes: z.string().optional(),
+  nextFollowupDate: z.string().optional().nullable(),
+  nextAction: z.string().optional()
+});
+
+export type EnquiryFormValues = z.input<typeof enquirySchema>;
+export type EnquiryFollowupFormValues = z.input<typeof enquiryFollowupSchema>;
diff --git a/src/features/crm/enquiries/server/service.ts b/src/features/crm/enquiries/server/service.ts
new file mode 100644
index 0000000..b573b88
--- /dev/null
+++ b/src/features/crm/enquiries/server/service.ts
@@ -0,0 +1,734 @@
+import { and, asc, count, desc, eq, ilike, inArray, isNull, or, type SQL } from 'drizzle-orm';
+import {
+  crmCustomerContacts,
+  crmCustomers,
+  crmEnquiries,
+  crmEnquiryFollowups,
+  users
+} from '@/db/schema';
+import { db } from '@/lib/db';
+import { AuthError } from '@/lib/auth/session';
+import { listAuditLogs } from '@/features/foundation/audit-log/service';
+import { getUserBranches, validateBranchAccess } from '@/features/foundation/branch-scope/service';
+import { generateNextDocumentCode } from '@/features/foundation/document-sequence/service';
+import { getActiveOptionsByCategory } from '@/features/foundation/master-options/service';
+import type {
+  EnquiryActivityRecord,
+  EnquiryBranchOption,
+  EnquiryContactLookup,
+  EnquiryCustomerLookup,
+  EnquiryCustomerRelationItem,
+  EnquiryFilters,
+  EnquiryFollowupMutationPayload,
+  EnquiryFollowupRecord,
+  EnquiryListItem,
+  EnquiryMutationPayload,
+  EnquiryOption,
+  EnquiryRecord,
+  EnquiryReferenceData
+} from '../api/types';
+
+const ENQUIRY_OPTION_CATEGORIES = {
+  status: 'crm_enquiry_status',
+  productType: 'crm_product_type',
+  priority: 'crm_priority',
+  leadChannel: 'crm_lead_channel',
+  followupType: 'crm_followup_type'
+} as const;
+
+function mapOption(
+  option: Awaited<ReturnType<typeof getActiveOptionsByCategory>>[number]
+): EnquiryOption {
+  return {
+    id: option.id,
+    code: option.code,
+    label: option.label,
+    value: option.value
+  };
+}
+
+function mapBranch(
+  branch: Awaited<ReturnType<typeof getUserBranches>>[number]
+): EnquiryBranchOption {
+  return {
+    id: branch.id,
+    code: branch.code,
+    name: branch.name,
+    value: branch.value
+  };
+}
+
+function mapEnquiryRecord(row: typeof crmEnquiries.$inferSelect): EnquiryRecord {
+  return {
+    id: row.id,
+    organizationId: row.organizationId,
+    branchId: row.branchId,
+    code: row.code,
+    customerId: row.customerId,
+    contactId: row.contactId,
+    title: row.title,
+    description: row.description,
+    requirement: row.requirement,
+    projectName: row.projectName,
+    projectLocation: row.projectLocation,
+    productType: row.productType,
+    status: row.status,
+    priority: row.priority,
+    leadChannel: row.leadChannel,
+    estimatedValue: row.estimatedValue,
+    chancePercent: row.chancePercent,
+    expectedCloseDate: row.expectedCloseDate?.toISOString() ?? null,
+    competitor: row.competitor,
+    source: row.source,
+    notes: row.notes,
+    isHotProject: row.isHotProject,
+    isActive: row.isActive,
+    createdAt: row.createdAt.toISOString(),
+    updatedAt: row.updatedAt.toISOString(),
+    deletedAt: row.deletedAt?.toISOString() ?? null,
+    createdBy: row.createdBy,
+    updatedBy: row.updatedBy
+  };
+}
+
+function mapFollowupRecord(row: typeof crmEnquiryFollowups.$inferSelect): EnquiryFollowupRecord {
+  return {
+    id: row.id,
+    organizationId: row.organizationId,
+    enquiryId: row.enquiryId,
+    followupDate: row.followupDate.toISOString(),
+    followupType: row.followupType,
+    contactId: row.contactId,
+    outcome: row.outcome,
+    notes: row.notes,
+    nextFollowupDate: row.nextFollowupDate?.toISOString() ?? null,
+    nextAction: row.nextAction,
+    createdAt: row.createdAt.toISOString(),
+    updatedAt: row.updatedAt.toISOString(),
+    deletedAt: row.deletedAt?.toISOString() ?? null,
+    createdBy: row.createdBy,
+    updatedBy: row.updatedBy
+  };
+}
+
+function parseSort(sort?: string) {
+  if (!sort) {
+    return desc(crmEnquiries.updatedAt);
+  }
+
+  try {
+    const parsed = JSON.parse(sort) as Array<{ id: string; desc?: boolean }>;
+    const [rule] = parsed;
+
+    if (!rule) {
+      return desc(crmEnquiries.updatedAt);
+    }
+
+    const sortMap = {
+      code: crmEnquiries.code,
+      title: crmEnquiries.title,
+      status: crmEnquiries.status,
+      priority: crmEnquiries.priority,
+      productType: crmEnquiries.productType,
+      branch: crmEnquiries.branchId,
+      customer: crmEnquiries.customerId,
+      updatedAt: crmEnquiries.updatedAt
+    } as const;
+
+    const column = sortMap[rule.id as keyof typeof sortMap];
+
+    if (!column) {
+      return desc(crmEnquiries.updatedAt);
+    }
+
+    return rule.desc ? desc(column) : asc(column);
+  } catch {
+    return desc(crmEnquiries.updatedAt);
+  }
+}
+
+function splitFilterValue(value?: string) {
+  return value
+    ? value
+        .split(/[.,]/)
+        .map((item) => item.trim())
+        .filter(Boolean)
+    : [];
+}
+
+async function resolveValidOptionIds(category: string, organizationId: string) {
+  const options = await getActiveOptionsByCategory(category, { organizationId });
+  return new Set(options.map((option) => option.id));
+}
+
+async function assertMasterOptionValue(
+  organizationId: string,
+  category: string,
+  optionId?: string | null
+) {
+  if (!optionId) {
+    return;
+  }
+
+  const validIds = await resolveValidOptionIds(category, organizationId);
+
+  if (!validIds.has(optionId)) {
+    throw new AuthError(`Invalid option for ${category}`, 400);
+  }
+}
+
+export async function assertCustomerBelongsToOrganization(id: string, organizationId: string) {
+  const customer = await db.query.crmCustomers.findFirst({
+    where: and(
+      eq(crmCustomers.id, id),
+      eq(crmCustomers.organizationId, organizationId),
+      isNull(crmCustomers.deletedAt)
+    )
+  });
+
+  if (!customer) {
+    throw new AuthError('Customer not found', 404);
+  }
+
+  return customer;
+}
+
+export async function assertContactBelongsToOrganization(
+  contactId: string,
+  organizationId: string,
+  customerId?: string | null
+) {
+  const contact = await db.query.crmCustomerContacts.findFirst({
+    where: and(
+      eq(crmCustomerContacts.id, contactId),
+      eq(crmCustomerContacts.organizationId, organizationId),
+      isNull(crmCustomerContacts.deletedAt),
+      ...(customerId ? [eq(crmCustomerContacts.customerId, customerId)] : [])
+    )
+  });
+
+  if (!contact) {
+    throw new AuthError('Contact not found', 404);
+  }
+
+  return contact;
+}
+
+async function assertEnquiryBelongsToOrganization(id: string, organizationId: string) {
+  const enquiry = await db.query.crmEnquiries.findFirst({
+    where: and(
+      eq(crmEnquiries.id, id),
+      eq(crmEnquiries.organizationId, organizationId),
+      isNull(crmEnquiries.deletedAt)
+    )
+  });
+
+  if (!enquiry) {
+    throw new AuthError('Enquiry not found', 404);
+  }
+
+  return enquiry;
+}
+
+async function assertFollowupBelongsToEnquiry(
+  followupId: string,
+  enquiryId: string,
+  organizationId: string
+) {
+  const followup = await db.query.crmEnquiryFollowups.findFirst({
+    where: and(
+      eq(crmEnquiryFollowups.id, followupId),
+      eq(crmEnquiryFollowups.enquiryId, enquiryId),
+      eq(crmEnquiryFollowups.organizationId, organizationId),
+      isNull(crmEnquiryFollowups.deletedAt)
+    )
+  });
+
+  if (!followup) {
+    throw new AuthError('Follow-up not found', 404);
+  }
+
+  return followup;
+}
+
+async function validateEnquiryPayload(organizationId: string, payload: EnquiryMutationPayload) {
+  await assertCustomerBelongsToOrganization(payload.customerId, organizationId);
+
+  if (payload.contactId) {
+    await assertContactBelongsToOrganization(payload.contactId, organizationId, payload.customerId);
+  }
+
+  await assertMasterOptionValue(organizationId, ENQUIRY_OPTION_CATEGORIES.status, payload.status);
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.productType,
+    payload.productType
+  );
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.priority,
+    payload.priority
+  );
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.leadChannel,
+    payload.leadChannel ?? null
+  );
+
+  if (payload.branchId) {
+    await validateBranchAccess(payload.branchId);
+  }
+}
+
+async function validateFollowupPayload(
+  organizationId: string,
+  enquiryId: string,
+  payload: EnquiryFollowupMutationPayload
+) {
+  const enquiry = await assertEnquiryBelongsToOrganization(enquiryId, organizationId);
+
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.followupType,
+    payload.followupType
+  );
+
+  if (payload.contactId) {
+    await assertContactBelongsToOrganization(payload.contactId, organizationId, enquiry.customerId);
+  }
+}
+
+function buildEnquiryFilters(organizationId: string, filters: EnquiryFilters): SQL[] {
+  const statuses = splitFilterValue(filters.status);
+  const productTypes = splitFilterValue(filters.productType);
+  const priorities = splitFilterValue(filters.priority);
+  const branches = splitFilterValue(filters.branch);
+  const customers = splitFilterValue(filters.customer);
+
+  return [
+    eq(crmEnquiries.organizationId, organizationId),
+    isNull(crmEnquiries.deletedAt),
+    ...(statuses.length ? [inArray(crmEnquiries.status, statuses)] : []),
+    ...(productTypes.length ? [inArray(crmEnquiries.productType, productTypes)] : []),
+    ...(priorities.length ? [inArray(crmEnquiries.priority, priorities)] : []),
+    ...(branches.length ? [inArray(crmEnquiries.branchId, branches)] : []),
+    ...(customers.length ? [inArray(crmEnquiries.customerId, customers)] : []),
+    ...(filters.search
+      ? [
+          or(
+            ilike(crmEnquiries.code, `%${filters.search}%`),
+            ilike(crmEnquiries.title, `%${filters.search}%`),
+            ilike(crmEnquiries.projectName, `%${filters.search}%`),
+            ilike(crmEnquiries.competitor, `%${filters.search}%`)
+          )!
+        ]
+      : [])
+  ];
+}
+
+export async function getEnquiryReferenceData(
+  organizationId: string
+): Promise<EnquiryReferenceData> {
+  const [
+    branches,
+    statuses,
+    productTypes,
+    priorities,
+    leadChannels,
+    followupTypes,
+    customers,
+    contacts
+  ] = await Promise.all([
+    getUserBranches(),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.status, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.productType, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.priority, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.leadChannel, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.followupType, { organizationId }),
+    db.query.crmCustomers.findMany({
+      where: and(eq(crmCustomers.organizationId, organizationId), isNull(crmCustomers.deletedAt)),
+      orderBy: [asc(crmCustomers.name)]
+    }),
+    db.query.crmCustomerContacts.findMany({
+      where: and(
+        eq(crmCustomerContacts.organizationId, organizationId),
+        isNull(crmCustomerContacts.deletedAt)
+      ),
+      orderBy: [desc(crmCustomerContacts.isPrimary), asc(crmCustomerContacts.name)]
+    })
+  ]);
+
+  return {
+    branches: branches.map(mapBranch),
+    statuses: statuses.map(mapOption),
+    productTypes: productTypes.map(mapOption),
+    priorities: priorities.map(mapOption),
+    leadChannels: leadChannels.map(mapOption),
+    followupTypes: followupTypes.map(mapOption),
+    customers: customers.map((customer) => ({
+      id: customer.id,
+      code: customer.code,
+      name: customer.name,
+      branchId: customer.branchId
+    })),
+    contacts: contacts.map((contact) => ({
+      id: contact.id,
+      customerId: contact.customerId,
+      name: contact.name,
+      email: contact.email,
+      mobile: contact.mobile,
+      isPrimary: contact.isPrimary
+    }))
+  };
+}
+
+export async function listEnquiries(
+  organizationId: string,
+  filters: EnquiryFilters
+): Promise<{ items: EnquiryListItem[]; totalItems: number }> {
+  const page = filters.page ?? 1;
+  const limit = filters.limit ?? 10;
+  const whereFilters = buildEnquiryFilters(organizationId, filters);
+  const where = whereFilters.length === 1 ? whereFilters[0] : and(...whereFilters);
+  const offset = (page - 1) * limit;
+
+  const [totalResult] = await db.select({ value: count() }).from(crmEnquiries).where(where);
+  const rows = await db
+    .select()
+    .from(crmEnquiries)
+    .where(where)
+    .orderBy(parseSort(filters.sort))
+    .limit(limit)
+    .offset(offset);
+
+  const customerIds = [...new Set(rows.map((row) => row.customerId))];
+  const contactIds = [...new Set(rows.map((row) => row.contactId).filter(Boolean) as string[])];
+  const enquiryIds = rows.map((row) => row.id);
+
+  const [customers, contacts, followupCounts] = await Promise.all([
+    customerIds.length
+      ? db.query.crmCustomers.findMany({
+          where: and(
+            eq(crmCustomers.organizationId, organizationId),
+            inArray(crmCustomers.id, customerIds)
+          )
+        })
+      : [],
+    contactIds.length
+      ? db.query.crmCustomerContacts.findMany({
+          where: and(
+            eq(crmCustomerContacts.organizationId, organizationId),
+            inArray(crmCustomerContacts.id, contactIds)
+          )
+        })
+      : [],
+    enquiryIds.length
+      ? db
+          .select({
+            enquiryId: crmEnquiryFollowups.enquiryId,
+            value: count()
+          })
+          .from(crmEnquiryFollowups)
+          .where(
+            and(
+              eq(crmEnquiryFollowups.organizationId, organizationId),
+              inArray(crmEnquiryFollowups.enquiryId, enquiryIds),
+              isNull(crmEnquiryFollowups.deletedAt)
+            )
+          )
+          .groupBy(crmEnquiryFollowups.enquiryId)
+      : []
+  ]);
+
+  const customerMap = new Map(customers.map((customer) => [customer.id, customer.name]));
+  const contactMap = new Map(contacts.map((contact) => [contact.id, contact.name]));
+  const followupCountMap = new Map(followupCounts.map((item) => [item.enquiryId, item.value]));
+
+  return {
+    items: rows.map((row) => ({
+      ...mapEnquiryRecord(row),
+      customerName: customerMap.get(row.customerId) ?? 'Unknown customer',
+      contactName: row.contactId ? (contactMap.get(row.contactId) ?? null) : null,
+      followupCount: followupCountMap.get(row.id) ?? 0
+    })),
+    totalItems: totalResult?.value ?? 0
+  };
+}
+
+export async function getEnquiryDetail(id: string, organizationId: string): Promise<EnquiryRecord> {
+  const enquiry = await assertEnquiryBelongsToOrganization(id, organizationId);
+  return mapEnquiryRecord(enquiry);
+}
+
+export async function getEnquiryActivity(
+  id: string,
+  organizationId: string
+): Promise<EnquiryActivityRecord[]> {
+  const auditLogs = await listAuditLogs({
+    organizationId,
+    entityId: id,
+    limit: 30
+  });
+  const filteredLogs = auditLogs.filter(
+    (log) =>
+      (log.entityType === 'crm_enquiry' && log.entityId === id) ||
+      (log.entityType === 'crm_enquiry_followup' &&
+        ((log.afterData as { enquiryId?: string } | null)?.enquiryId === id ||
+          (log.beforeData as { enquiryId?: string } | null)?.enquiryId === id))
+  );
+  const userIds = [...new Set(filteredLogs.map((log) => log.userId))];
+  const actorRows = userIds.length
+    ? await db
+        .select({ id: users.id, name: users.name })
+        .from(users)
+        .where(inArray(users.id, userIds))
+    : [];
+  const actorMap = new Map(actorRows.map((row) => [row.id, row.name]));
+
+  return filteredLogs.map((log) => ({
+    id: log.id,
+    action: log.action,
+    entityType: log.entityType,
+    entityId: log.entityId,
+    createdAt: log.createdAt,
+    userId: log.userId,
+    actorName: actorMap.get(log.userId) ?? null
+  }));
+}
+
+export async function createEnquiry(
+  organizationId: string,
+  userId: string,
+  payload: EnquiryMutationPayload
+) {
+  await validateEnquiryPayload(organizationId, payload);
+
+  const documentCode = await generateNextDocumentCode({
+    organizationId,
+    documentType: 'enquiry',
+    branchId: payload.branchId ?? ''
+  });
+
+  const [created] = await db
+    .insert(crmEnquiries)
+    .values({
+      id: crypto.randomUUID(),
+      organizationId,
+      branchId: payload.branchId ?? null,
+      code: documentCode.code,
+      customerId: payload.customerId,
+      contactId: payload.contactId ?? null,
+      title: payload.title.trim(),
+      description: payload.description?.trim() || null,
+      requirement: payload.requirement?.trim() || null,
+      projectName: payload.projectName?.trim() || null,
+      projectLocation: payload.projectLocation?.trim() || null,
+      productType: payload.productType,
+      status: payload.status,
+      priority: payload.priority,
+      leadChannel: payload.leadChannel ?? null,
+      estimatedValue: payload.estimatedValue ?? null,
+      chancePercent: payload.chancePercent ?? null,
+      expectedCloseDate: payload.expectedCloseDate ? new Date(payload.expectedCloseDate) : null,
+      competitor: payload.competitor?.trim() || null,
+      source: payload.source?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      isHotProject: payload.isHotProject ?? false,
+      isActive: payload.isActive ?? true,
+      createdBy: userId,
+      updatedBy: userId
+    })
+    .returning();
+
+  return created;
+}
+
+export async function updateEnquiry(
+  id: string,
+  organizationId: string,
+  userId: string,
+  payload: EnquiryMutationPayload
+) {
+  await validateEnquiryPayload(organizationId, payload);
+  await assertEnquiryBelongsToOrganization(id, organizationId);
+
+  const [updated] = await db
+    .update(crmEnquiries)
+    .set({
+      branchId: payload.branchId ?? null,
+      customerId: payload.customerId,
+      contactId: payload.contactId ?? null,
+      title: payload.title.trim(),
+      description: payload.description?.trim() || null,
+      requirement: payload.requirement?.trim() || null,
+      projectName: payload.projectName?.trim() || null,
+      projectLocation: payload.projectLocation?.trim() || null,
+      productType: payload.productType,
+      status: payload.status,
+      priority: payload.priority,
+      leadChannel: payload.leadChannel ?? null,
+      estimatedValue: payload.estimatedValue ?? null,
+      chancePercent: payload.chancePercent ?? null,
+      expectedCloseDate: payload.expectedCloseDate ? new Date(payload.expectedCloseDate) : null,
+      competitor: payload.competitor?.trim() || null,
+      source: payload.source?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      isHotProject: payload.isHotProject ?? false,
+      isActive: payload.isActive ?? true,
+      updatedBy: userId,
+      updatedAt: new Date()
+    })
+    .where(eq(crmEnquiries.id, id))
+    .returning();
+
+  return updated;
+}
+
+export async function softDeleteEnquiry(id: string, organizationId: string, userId: string) {
+  await assertEnquiryBelongsToOrganization(id, organizationId);
+  const now = new Date();
+
+  const [updated] = await db
+    .update(crmEnquiries)
+    .set({
+      deletedAt: now,
+      updatedAt: now,
+      updatedBy: userId,
+      isActive: false
+    })
+    .where(eq(crmEnquiries.id, id))
+    .returning();
+
+  await db
+    .update(crmEnquiryFollowups)
+    .set({
+      deletedAt: now,
+      updatedAt: now,
+      updatedBy: userId
+    })
+    .where(
+      and(
+        eq(crmEnquiryFollowups.enquiryId, id),
+        eq(crmEnquiryFollowups.organizationId, organizationId)
+      )
+    );
+
+  return updated;
+}
+
+export async function listEnquiryFollowups(id: string, organizationId: string) {
+  await assertEnquiryBelongsToOrganization(id, organizationId);
+  const rows = await db.query.crmEnquiryFollowups.findMany({
+    where: and(
+      eq(crmEnquiryFollowups.enquiryId, id),
+      eq(crmEnquiryFollowups.organizationId, organizationId),
+      isNull(crmEnquiryFollowups.deletedAt)
+    ),
+    orderBy: [desc(crmEnquiryFollowups.followupDate)]
+  });
+
+  return rows.map(mapFollowupRecord);
+}
+
+export async function createEnquiryFollowup(
+  enquiryId: string,
+  organizationId: string,
+  userId: string,
+  payload: EnquiryFollowupMutationPayload
+) {
+  await validateFollowupPayload(organizationId, enquiryId, payload);
+
+  const [created] = await db
+    .insert(crmEnquiryFollowups)
+    .values({
+      id: crypto.randomUUID(),
+      organizationId,
+      enquiryId,
+      followupDate: new Date(payload.followupDate),
+      followupType: payload.followupType,
+      contactId: payload.contactId ?? null,
+      outcome: payload.outcome?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      nextFollowupDate: payload.nextFollowupDate ? new Date(payload.nextFollowupDate) : null,
+      nextAction: payload.nextAction?.trim() || null,
+      createdBy: userId,
+      updatedBy: userId
+    })
+    .returning();
+
+  return created;
+}
+
+export async function updateEnquiryFollowup(
+  enquiryId: string,
+  followupId: string,
+  organizationId: string,
+  userId: string,
+  payload: EnquiryFollowupMutationPayload
+) {
+  await validateFollowupPayload(organizationId, enquiryId, payload);
+  await assertFollowupBelongsToEnquiry(followupId, enquiryId, organizationId);
+
+  const [updated] = await db
+    .update(crmEnquiryFollowups)
+    .set({
+      followupDate: new Date(payload.followupDate),
+      followupType: payload.followupType,
+      contactId: payload.contactId ?? null,
+      outcome: payload.outcome?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      nextFollowupDate: payload.nextFollowupDate ? new Date(payload.nextFollowupDate) : null,
+      nextAction: payload.nextAction?.trim() || null,
+      updatedAt: new Date(),
+      updatedBy: userId
+    })
+    .where(eq(crmEnquiryFollowups.id, followupId))
+    .returning();
+
+  return updated;
+}
+
+export async function softDeleteEnquiryFollowup(
+  enquiryId: string,
+  followupId: string,
+  organizationId: string,
+  userId: string
+) {
+  await assertFollowupBelongsToEnquiry(followupId, enquiryId, organizationId);
+
+  const [updated] = await db
+    .update(crmEnquiryFollowups)
+    .set({
+      deletedAt: new Date(),
+      updatedAt: new Date(),
+      updatedBy: userId
+    })
+    .where(eq(crmEnquiryFollowups.id, followupId))
+    .returning();
+
+  return updated;
+}
+
+export async function listCustomerEnquiryRelations(
+  customerId: string,
+  organizationId: string
+): Promise<EnquiryCustomerRelationItem[]> {
+  const rows = await db.query.crmEnquiries.findMany({
+    where: and(
+      eq(crmEnquiries.customerId, customerId),
+      eq(crmEnquiries.organizationId, organizationId),
+      isNull(crmEnquiries.deletedAt)
+    ),
+    orderBy: [desc(crmEnquiries.updatedAt)],
+    limit: 10
+  });
+
+  return rows.map((row) => ({
+    id: row.id,
+    code: row.code,
+    title: row.title,
+    status: row.status,
+    productType: row.productType,
+    updatedAt: row.updatedAt.toISOString()
+  }));
+}
diff --git a/src/lib/auth/rbac.ts b/src/lib/auth/rbac.ts
index 6f05b4a..e406f17 100644
--- a/src/lib/auth/rbac.ts
+++ b/src/lib/auth/rbac.ts
@@ -26,7 +26,15 @@ export const PERMISSIONS = {
   crmContactRead: 'crm.contact.read',
   crmContactCreate: 'crm.contact.create',
   crmContactUpdate: 'crm.contact.update',
-  crmContactDelete: 'crm.contact.delete'
+  crmContactDelete: 'crm.contact.delete',
+  crmEnquiryRead: 'crm.enquiry.read',
+  crmEnquiryCreate: 'crm.enquiry.create',
+  crmEnquiryUpdate: 'crm.enquiry.update',
+  crmEnquiryDelete: 'crm.enquiry.delete',
+  crmEnquiryFollowupRead: 'crm.enquiry.followup.read',
+  crmEnquiryFollowupCreate: 'crm.enquiry.followup.create',
+  crmEnquiryFollowupUpdate: 'crm.enquiry.followup.update',
+  crmEnquiryFollowupDelete: 'crm.enquiry.followup.delete'
 } as const;
 
 export type Permission = (typeof PERMISSIONS)[keyof typeof PERMISSIONS];
@@ -45,11 +53,25 @@ function getMembershipBasePermissions(role: MembershipRole): Permission[] {
       PERMISSIONS.crmContactRead,
       PERMISSIONS.crmContactCreate,
       PERMISSIONS.crmContactUpdate,
-      PERMISSIONS.crmContactDelete
+      PERMISSIONS.crmContactDelete,
+      PERMISSIONS.crmEnquiryRead,
+      PERMISSIONS.crmEnquiryCreate,
+      PERMISSIONS.crmEnquiryUpdate,
+      PERMISSIONS.crmEnquiryDelete,
+      PERMISSIONS.crmEnquiryFollowupRead,
+      PERMISSIONS.crmEnquiryFollowupCreate,
+      PERMISSIONS.crmEnquiryFollowupUpdate,
+      PERMISSIONS.crmEnquiryFollowupDelete
     ];
   }
 
-  return [PERMISSIONS.productsRead, PERMISSIONS.crmCustomerRead, PERMISSIONS.crmContactRead];
+  return [
+    PERMISSIONS.productsRead,
+    PERMISSIONS.crmCustomerRead,
+    PERMISSIONS.crmContactRead,
+    PERMISSIONS.crmEnquiryRead,
+    PERMISSIONS.crmEnquiryFollowupRead
+  ];
 }
 
 export function getBusinessRolePermissions(role: BusinessRole): Permission[] {
diff --git a/src/lib/searchparams.ts b/src/lib/searchparams.ts
index 1dae4c3..d5d711d 100644
--- a/src/lib/searchparams.ts
+++ b/src/lib/searchparams.ts
@@ -13,8 +13,10 @@ export const searchParams = {
   category: parseAsString,
   customerType: parseAsString,
   customerStatus: parseAsString,
+  customer: parseAsString,
   branch: parseAsString,
   productType: parseAsString,
+  priority: parseAsString,
   salesman: parseAsString,
   dateFrom: parseAsString,
   dateTo: parseAsString,