API testing guides — test REST and GraphQL APIs, write contract tests, and automate API validation.
Testing
API backward compatibility testing is one of the most critical — and most overlooked — disciplines in microservices engineering. A single breaking change pushed to a shared API can cascade into production failures across a dozen downstream services, and the failure often surfaces hours after the deployment in a way that'
API Testing
API testing has become one of the most critical skills in modern software quality engineering. As applications shift toward microservices and mobile-first architectures, APIs carry the lion's share of business logic — and bugs found at the API level are far cheaper to fix than those discovered through the
API Testing
Frontend development has a classic blocking problem: the backend isn't ready. You're building a checkout flow, but the payments API returns a 500. You want to test the empty state, but the backend always returns data. You need to simulate a 429 rate limit, but production
API Testing
You can't write a test for every possible input. A string field accepts billions of values. A numeric parameter has edge cases you haven't considered. An API that looks solid against your 20 hand-written test cases might crash on the 21st input — the one a real
API Testing
Writing API tests by hand means writing a lot of boilerplate: constructing URLs, setting headers, serializing request bodies, parsing responses. When the API changes, you update the tests manually and hope you caught every callsite. OpenAPI Generator eliminates that boilerplate. Given an OpenAPI spec, it generates a fully typed API
API Testing
Both Dredd and Schemathesis test whether your API implementation matches its spec. Both read OpenAPI (or API Blueprint) definitions and make real HTTP requests. Beyond that, they take fundamentally different approaches — and understanding the difference determines which one belongs in your pipeline. The Core Difference Dredd is deterministic. It reads
API Testing
API contracts are promises. Your OpenAPI specification says "this endpoint returns a userId field of type string." Every consumer of your API — mobile apps, partner integrations, frontend teams — builds against that promise. When the promise breaks silently, you get production incidents, not compiler errors. Spectral is a linter
API Testing
Most teams write code first, then document it. The API exists; you write the OpenAPI spec to describe what you built. This approach has a persistent problem: the code and the documentation diverge. Consumers get specs that don't match the real behavior. Tests get written against the implementation,
Testing
Locust is a Python-based load testing tool with a simple, expressive API. Unlike k6 (JavaScript) or Gatling (Scala/Java), Locust lets you write tests in plain Python — making it especially accessible for backend developers and data engineers already working in the language. This guide focuses on stress testing REST APIs
Testing
A well-tested SaaS API is one of the strongest competitive advantages a product can have. Developers who integrate your API need to trust that authentication works predictably, rate limits are enforced fairly, and older API versions continue to behave as documented. When any of these break, the cost is not
Testing
APIs are the backbone of modern applications. They are also the primary attack surface. While web application security testing has decades of tooling and methodology behind it, API security testing is often treated as an afterthought — a Postman collection with some happy path tests and nothing more. This guide changes
Testing
Every development team has some informal way of documenting API calls. Slack messages with curl commands. Postman collections that live on one person's laptop. A wiki page with example requests that went stale three sprints ago. None of these are good solutions. The VS Code REST Client extension