API contract testing

API contract testing ensures your frontend and backend stay in sync. Check Studio integrates with Playwright request fixtures to validate responses against OpenAPI specs.

Setup

1. 1Export your OpenAPI spec to openapi.json in the project root
2. 2Install the contract testing add-on: npm install -D @checkstudio/contract-testing
3. 3Add the fixture to your test config

Writing a contract test

test('GET /users returns valid response', async ({ request, contract }) => {
  const response = await request.get('/api/users');
  await contract.validate(response, { schema: 'UserList' });
  expect(response.status()).toBe(200);
});