API Testing

APIRequestContext Basics

Call request.get/post/put/patch/delete with relative paths against baseURL. Pass data for JSON, headers for auth, params for query strings.

API tests validate backend contracts independently; use them to seed data before UI tests or verify endpoints the UI depends on.

test('creates order via API', async ({ request }) => {
  const res = await request.post('/api/orders', {
    data: { productId: 'sku-1', qty: 2 },
    headers: { Authorization: 'Bearer test-token' },
  });
  expect(res.status()).toBe(201);
  const { orderId } = await res.json();
  expect(orderId).toBeTruthy();
});

request respects baseURL and extraHTTPHeaders from config.

HTTP Methods

await request.get('/api/items')
await request.post('/api/items', { data: { name: 'x' } })
await request.put('/api/items/1', { data: { name: 'y' } })
await request.delete('/api/items/1')

• data serializes to JSON with content-type application/json.
• form and multipart for other content types.
• failOnStatusCode: false prevents throw on 4xx/5xx.
• Share storageState between browser and API contexts.

API Testing Reference

request fixture quick reference.

API Setup + UI Verification

test('shows order in UI', async ({ page, request }) => {
  const res = await request.post('/api/orders', { data: { sku: 'A' } });
  const { id } = await res.json();
  await page.goto(`/orders/${id}`);
  await expect(page.getByText('Order confirmed')).toBeVisible();
});

API Tests for Setup

Create test users via request.post('/api/users') in beforeAll faster than driving registration UI — then use storageState for browser tests.

Common Mistakes

• Testing only status code, not response body shape.
• API tests hitting same prod endpoints as E2E.
• Not cleaning up created entities.
• Missing auth on protected endpoints.

Key Takeaways

• request fixture enables fast HTTP testing.
• Seed UI tests via API for speed.
• Validate status, headers, and JSON body.
• Align API tests with contract expectations.