QA ENGINEERING GUIDE

HTTP Status Codes Explained

Understand HTTP 2xx, 3xx, 4xx and 5xx responses with QA examples.

2xx — success

200 means a request succeeded, 201 usually means a resource was created, and 204 indicates success with no response body.

3xx — redirection

3xx responses communicate redirects or cache-related behavior. Test whether clients follow redirects as expected and whether the Location header is correct.

4xx — client-side request problems

400 commonly represents an invalid request, 401 authentication is required, 403 access is forbidden, 404 means a resource was not found and 429 indicates rate limiting.

5xx — server-side failures

500 represents an internal server failure, 502 commonly indicates an invalid upstream response and 503 indicates temporary service unavailability.

Testing strategy

For each endpoint, define expected status codes for successful, validation, authentication, authorization, not-found and unexpected conditions.