API testing guides — test REST and GraphQL APIs, write contract tests, and automate API validation.
Testing
REST Assured's API was designed around the Given-When-Then structure from Behavior-Driven Development. This isn't just a cosmetic choice — tests written in BDD style are executable documentation. They describe what an API is supposed to do in terms that developers, QA engineers, and product managers can all
Testing
Postman and REST Assured are both popular tools for API testing, but they serve different needs and different teams. Choosing between them — or deciding to use both — requires understanding what each does well and where each falls short. Quick Overview Postman is a GUI-based API platform. You build requests visually,
Testing
E2E testing for GraphQL-powered apps requires different techniques than REST APIs. With REST, you intercept by URL (/api/users). With GraphQL, every query hits the same endpoint (/graphql), so you intercept by operation name or query content. Both Playwright and Cypress support GraphQL intercepting well. This guide shows you how
Testing
Apollo Server's executeOperation is excellent for most GraphQL testing. But sometimes you need to test the full HTTP stack — middleware, authentication headers, CORS, rate limiting, and HTTP error codes. Supertest lets you do that: it sends real HTTP requests against your Express/Fastify application without starting a network
Testing
Apollo Server is the most popular GraphQL server for Node.js. Its testing story is surprisingly good: executeOperation lets you run queries against an in-memory server without HTTP overhead, making integration tests fast and deterministic. This guide focuses on the practical patterns you need for testing Apollo Server 4 applications
Testing
Testing GraphQL APIs is fundamentally different from testing REST. With REST, each endpoint has a specific contract. With GraphQL, a single endpoint handles arbitrary queries, and the surface area is determined by your schema. A change to a resolver can affect dozens of queries the client might send. This guide
Testing
GraphQL schema evolution is a double-edged sword. The schema gives you a formal contract between clients and servers. But that contract is only useful if you enforce it — if you can detect when a server-side change would break existing clients before it reaches production. This guide covers the tools and
Testing
If you've ever mocked an API by patching fetch, overriding axios.get, or wrestling with nock's obscure intercept API, you know the pain. Your mock and your real network call look nothing alike. The mock breaks when you refactor your fetching logic. And none of it
Testing
GraphQL APIs break most REST testing assumptions. One endpoint, unlimited query shapes, typed schemas, subscriptions — it's a different beast. This guide covers the full testing stack: unit tests for resolvers, integration tests with supertest, Apollo MockedProvider for component testing, schema validation, subscription testing, and E2E automation. What Makes
Test Automation
API test automation verifies that your backend endpoints return correct data, status codes, and response times — automatically, on every code change. Use Python + requests + pytest for code-first testing, or Postman/Newman for GUI-first. Key tests: status codes, response schemas, auth flows, error handling, and edge cases. Integrate into GitHub Actions
Test Automation
Every feature your users love is held together by API calls you never see. When one of those calls fails silently, your frontend shows stale data, your mobile app crashes, and your users think it's a bug in the UI. API testing catches the real failures — before your