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API tests are faster, more stable, and catch bugs the UI never shows. Learn how to write them directly in Playwright without any extra tools.

You already have Playwright installed — here's how to use its built-in HTTP client to test APIs, seed test data, and ditch Postman for good.

API testing shouldn't be a fallback for when the UI breaks — it should be the first line of defense for every backend feature you ship.

The UI says "Order placed" — SQL tells you whether the record actually landed in the database.

Your Playwright tests pass — but do they pass with 500 users hitting the API at once? Learn k6 from first script to CI-integrated load test with thresholds that actually fail your build.

Most auth bugs live in the gaps — the endpoint that returns 200 when it should 401, the admin route that accepts a regular user's token. Learn to test all of it.

Frontend and backend both pass their own tests — but the API contract between them breaks in staging every other sprint. Contract testing with Pact closes that gap.

GraphQL always returns 200 — even for errors. Here's how to test GraphQL APIs with Playwright, handle the error model correctly, and build reusable query fixtures.

Postman collections don't run in CI without a paid plan. Playwright's request fixture does the same job, lives in your repo, and runs anywhere. Here's the migration playbook.

Every modern app you test communicates with a backend through APIs. Understand HTTP requests, status codes, authentication, and how to inspect API calls — without building one yourself.

You're watching the Network tab. A request returns 422. Is that expected? A bug? Should you file a ticket? Every QA engineer who works with APIs needs to know the status codes that actually matter.

Postman is where most QA engineers start with API testing. You don't need to write code to send requests, inspect responses, and verify your backend works correctly.