diff --git a/src/test/transactions.e2e.spec.ts b/src/test/transactions.e2e.spec.ts
new file mode 100644
index 0000000..82bffbe
--- /dev/null
+++ b/src/test/transactions.e2e.spec.ts
@@ -0,0 +1,177 @@
+/**
+ * TST-005: Transactions API Integration Tests (CC-047)
+ *
+ * Tests HTTP contract of TransactionsController:
+ *   - validation of amountMinorUnits as integer
+ *   - currency and evidenceStatus validation
+ *   - ParseUUIDPipe on path params
+ *   - response shapes
+ */
+import request from 'supertest';
+import {
+  CanActivate,
+  ExecutionContext,
+  Injectable,
+  UnauthorizedException,
+  INestApplication,
+  ValidationPipe,
+  Module,
+} from '@nestjs/common';
+import { Reflector } from '@nestjs/core';
+import { Test, type TestingModule } from '@nestjs/testing';
+import helmet from 'helmet';
+import { ConfigModule } from '@nestjs/config';
+import { APP_GUARD } from '@nestjs/core';
+import { TransactionsController } from '../transactions/transactions.controller';
+import { TransactionsService } from '../transactions/transactions.service';
+
+const FAKE_SESSION = {
+  requestId: 'req-1', correlationId: 'cor-1', sessionId: 'ses-1',
+  userId: '00000000-0000-0000-0000-000000000001',
+  tenantId: '00000000-0000-0000-0000-000000000002',
+  workspaceId: '00000000-0000-0000-0000-000000000003',
+  membershipId: '00000000-0000-0000-0000-000000000004',
+  role: 'owner' as const, roles: ['owner' as const],
+  permissions: ['*'], purpose: 'test', timezone: 'UTC', source: 'api' as const,
+};
+
+@Injectable()
+class StubAuthGuard implements CanActivate {
+  constructor(private readonly reflector: Reflector) {}
+  canActivate(context: ExecutionContext): boolean {
+    const req = context.switchToHttp().getRequest<{ headers: Record<string, string>; session?: typeof FAKE_SESSION }>();
+    const auth = req.headers['authorization'] ?? '';
+    if (!auth.startsWith('Bearer ') || !auth.slice(7).trim()) throw new UnauthorizedException();
+    req.session = FAKE_SESSION;
+    return true;
+  }
+}
+
+const MOCK_TX = {
+  id: '00000000-0000-0000-0000-bbbb00000001',
+  tenantId: FAKE_SESSION.tenantId,
+  organizationId: '00000000-0000-0000-0000-000000000005',
+  type: 'invoice',
+  amountMinorUnits: '123400',
+  currency: 'EUR',
+  transactionDate: '2026-07-31',
+  evidenceStatus: 'missing',
+  createdAt: new Date(),
+  updatedAt: new Date(),
+};
+
+const mockTxService = {
+  list: jest.fn().mockResolvedValue([MOCK_TX]),
+  getById: jest.fn().mockResolvedValue(MOCK_TX),
+  create: jest.fn().mockResolvedValue(MOCK_TX),
+  updateEvidence: jest.fn().mockResolvedValue({ ...MOCK_TX, evidenceStatus: 'complete' }),
+};
+
+@Module({
+  imports: [ConfigModule.forRoot({ isGlobal: true })],
+  controllers: [TransactionsController],
+  providers: [
+    { provide: TransactionsService, useValue: mockTxService },
+    { provide: APP_GUARD, useClass: StubAuthGuard },
+  ],
+})
+class TxTestModule {}
+
+const AUTH = 'Bearer test-token';
+const VALID_UUID = '00000000-0000-0000-0000-bbbb00000001';
+const VALID_ORG_UUID = '00000000-0000-0000-0000-000000000005';
+
+describe('TST-005: Transactions API Integration', () => {
+  let app: INestApplication;
+
+  beforeAll(async () => {
+    const module: TestingModule = await Test.createTestingModule({ imports: [TxTestModule] }).compile();
+    app = module.createNestApplication();
+    app.use(helmet());
+    app.useGlobalPipes(new ValidationPipe({ whitelist: true, forbidNonWhitelisted: true, transform: true }));
+    app.setGlobalPrefix('v1');
+    await app.init();
+  });
+
+  afterAll(() => app.close());
+  beforeEach(() => jest.clearAllMocks());
+
+  describe('POST /v1/transactions', () => {
+    const VALID_BODY = {
+      organizationId: VALID_ORG_UUID,
+      type: 'invoice',
+      amountMinorUnits: 123400,
+      currency: 'EUR',
+      transactionDate: '2026-07-31',
+      evidenceStatus: 'missing',
+    };
+
+    it('returns 201 with valid body', async () => {
+      await request(app.getHttpServer())
+        .post('/v1/transactions')
+        .set('Authorization', AUTH)
+        .send(VALID_BODY)
+        .expect(201);
+      expect(mockTxService.create).toHaveBeenCalledTimes(1);
+    });
+
+    it('returns 400 when amountMinorUnits is float', async () => {
+      await request(app.getHttpServer())
+        .post('/v1/transactions')
+        .set('Authorization', AUTH)
+        .send({ ...VALID_BODY, amountMinorUnits: 1234.56 })
+        .expect(400);
+    });
+
+    it('returns 400 when amountMinorUnits is negative', async () => {
+      await request(app.getHttpServer())
+        .post('/v1/transactions')
+        .set('Authorization', AUTH)
+        .send({ ...VALID_BODY, amountMinorUnits: -100 })
+        .expect(400);
+    });
+
+    it('returns 400 when evidenceStatus is invalid', async () => {
+      await request(app.getHttpServer())
+        .post('/v1/transactions')
+        .set('Authorization', AUTH)
+        .send({ ...VALID_BODY, evidenceStatus: 'unknown_status' })
+        .expect(400);
+    });
+
+    it('returns 400 when organizationId is not UUID', async () => {
+      await request(app.getHttpServer())
+        .post('/v1/transactions')
+        .set('Authorization', AUTH)
+        .send({ ...VALID_BODY, organizationId: 'not-a-uuid' })
+        .expect(400);
+    });
+
+    it('returns 400 when required field missing (currency)', async () => {
+      const { currency: _c, ...bodyWithoutCurrency } = VALID_BODY;
+      await request(app.getHttpServer())
+        .post('/v1/transactions')
+        .set('Authorization', AUTH)
+        .send(bodyWithoutCurrency)
+        .expect(400);
+    });
+  });
+
+  describe('PATCH /v1/transactions/:id/evidence', () => {
+    it('returns 200 with valid UUID and valid body', async () => {
+      await request(app.getHttpServer())
+        .patch(`/v1/transactions/${VALID_UUID}/evidence`)
+        .set('Authorization', AUTH)
+        .send({ evidenceStatus: 'complete' })
+        .expect(200);
+    });
+
+    it('returns 400 for non-UUID path param', async () => {
+      await request(app.getHttpServer())
+        .patch('/v1/transactions/not-a-uuid/evidence')
+        .set('Authorization', AUTH)
+        .send({ evidenceStatus: 'complete' })
+        .expect(400);
+    });
+  });
+});