diff --git a/src/test/transactions.e2e.spec.ts b/src/test/transactions.e2e.spec.ts
index a3798f1..df9f610 100644
--- a/src/test/transactions.e2e.spec.ts
+++ b/src/test/transactions.e2e.spec.ts
@@ -7,6 +7,8 @@
  *   - evidenceStatus enum validation on create + update
  *   - ParseUUIDPipe on path params
  *   - response shapes
+ *
+ * UUIDs are v4-compliant (version nibble=4, variant nibble=8) so @IsUUID() passes.
  */
 import request from 'supertest';
 import {
@@ -28,10 +30,10 @@ 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',
+  userId: '1a000000-0000-4000-8000-000000000001',
+  tenantId: '1a000000-0000-4000-8000-000000000002',
+  workspaceId: '1a000000-0000-4000-8000-000000000003',
+  membershipId: '1a000000-0000-4000-8000-000000000004',
   role: 'owner' as const, roles: ['owner' as const],
   permissions: ['*'], purpose: 'test', timezone: 'UTC', source: 'api' as const,
 };
@@ -49,9 +51,9 @@ class StubAuthGuard implements CanActivate {
 }
 
 const MOCK_TX = {
-  id: '00000000-0000-0000-0000-bbbb00000001',
-  tenantId: FAKE_SESSION.tenantId,
-  organizationId: '00000000-0000-0000-0000-000000000005',
+  id: '1a000000-0000-4000-8000-bbbb00000001',
+  tenantId: '1a000000-0000-4000-8000-000000000002',
+  organizationId: '1a000000-0000-4000-8000-000000000005',
   type: 'invoice',
   amountMinorUnits: '123400',
   currency: 'EUR',
@@ -80,8 +82,6 @@ const mockTxService = {
 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;
@@ -115,7 +115,7 @@ describe('TST-005: Transactions API Integration', () => {
 
   describe('POST /v1/transactions', () => {
     const VALID_BODY = {
-      organizationId: VALID_ORG_UUID,
+      organizationId: '1a000000-0000-4000-8000-000000000005',
       type: 'invoice',
       amountMinorUnits: 123400,
       currency: 'EUR',
@@ -184,7 +184,7 @@ describe('TST-005: Transactions API Integration', () => {
   describe('PATCH /v1/transactions/:id', () => {
     it('returns 200 with valid UUID and valid body', async () => {
       await request(app.getHttpServer())
-        .patch(`/v1/transactions/${VALID_UUID}`)
+        .patch('/v1/transactions/1a000000-0000-4000-8000-bbbb00000001')
         .set('Authorization', AUTH)
         .send({ evidenceStatus: 'complete' })
         .expect(200);
@@ -201,7 +201,7 @@ describe('TST-005: Transactions API Integration', () => {
 
     it('returns 400 for invalid evidenceStatus in body', async () => {
       await request(app.getHttpServer())
-        .patch(`/v1/transactions/${VALID_UUID}`)
+        .patch('/v1/transactions/1a000000-0000-4000-8000-bbbb00000001')
         .set('Authorization', AUTH)
         .send({ evidenceStatus: 'flying' })
         .expect(400);
@@ -211,7 +211,7 @@ describe('TST-005: Transactions API Integration', () => {
   describe('DELETE /v1/transactions/:id', () => {
     it('returns 200 with valid UUID', async () => {
       await request(app.getHttpServer())
-        .delete(`/v1/transactions/${VALID_UUID}`)
+        .delete('/v1/transactions/1a000000-0000-4000-8000-bbbb00000001')
         .set('Authorization', AUTH)
         .expect(200);
       expect(mockTxService.softDelete).toHaveBeenCalledTimes(1);