API Testing

This site has no backend of its own, so these exercises target DummyJSON and httpbin.org — free, public, CORS-enabled test APIs. The panel below is a small in-browser REST client: pick a preset to load a real request, or write your own, then send it and read the actual response.

Each preset's note tells you what to check — status code, response shape, specific field values. Writes (POST/PUT/DELETE) against DummyJSON are simulated and never persisted server-side — that's deliberate: exercise 7 and 8 exist specifically to teach you not to assume a 200 response means the data actually changed. Exercises 11–14 use httpbin's status endpoint purely to return specific HTTP status codes on demand — remember that fetch resolves for 4xx/5xx just like it does for 2xx, so checking response.ok is on you.