diff --git a/src/transactions/transactions.controller.ts b/src/transactions/transactions.controller.ts
new file mode 100644
index 0000000..3392d56
--- /dev/null
+++ b/src/transactions/transactions.controller.ts
@@ -0,0 +1,48 @@
+import { BadRequestException, Body, Controller, Delete, Get, Param, ParseUUIDPipe, Patch, Post, Query } from '@nestjs/common';
+import { CurrentSession } from '../auth/session.decorator';
+import type { AuthenticatedSession } from '../auth/tenant.guard';
+import { CreateTransactionDto, UpdateTransactionDto } from './dto';
+import { TransactionsService } from './transactions.service';
+
+@Controller('transactions')
+export class TransactionsController {
+  constructor(private readonly transactionsService: TransactionsService) {}
+
+  @Get()
+  list(
+    @CurrentSession() session: AuthenticatedSession,
+    @Query('organizationId') organizationId?: string,
+  ) {
+    if (organizationId) {
+      try { new (require('crypto').randomUUID)(); } catch { /* ok */ }
+      if (!/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(organizationId)) {
+        throw new BadRequestException('organizationId must be a valid UUID');
+      }
+    }
+    return this.transactionsService.list(session, organizationId);
+  }
+
+  @Get(':id')
+  getById(@CurrentSession() session: AuthenticatedSession, @Param('id', ParseUUIDPipe) id: string) {
+    return this.transactionsService.getById(session, id);
+  }
+
+  @Post()
+  create(@CurrentSession() session: AuthenticatedSession, @Body() dto: CreateTransactionDto) {
+    return this.transactionsService.create(session, dto);
+  }
+
+  @Patch(':id')
+  update(
+    @CurrentSession() session: AuthenticatedSession,
+    @Param('id', ParseUUIDPipe) id: string,
+    @Body() dto: UpdateTransactionDto,
+  ) {
+    return this.transactionsService.update(session, id, dto);
+  }
+
+  @Delete(':id')
+  softDelete(@CurrentSession() session: AuthenticatedSession, @Param('id', ParseUUIDPipe) id: string) {
+    return this.transactionsService.softDelete(session, id);
+  }
+}