What is the difference between 401 and 403?

401 Unauthorized means the request lacks valid authentication credentials. 403 Forbidden means the server understood the request but refuses to authorise it — even with valid credentials.

When should I use 422 vs 400?

400 Bad Request is for malformed syntax. 422 Unprocessable Entity is for well-formed requests that fail semantic validation (e.g., a valid JSON body with invalid business logic values).

What is the difference between 301 and 302?

301 Moved Permanently tells clients and search engines the URL has permanently changed — update your bookmarks and links. 302 Found is a temporary redirect — the original URL is still valid and should not be updated.

What does status 429 mean?

429 Too Many Requests means the client has exceeded the rate limit. The server may include a Retry-After header indicating how long to wait before sending another request.

HTTP Status Code Reference

A complete, searchable reference for all HTTP status codes — 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors. Each entry includes the code, official name, description, common use cases, and whether it is cacheable. Search by number or keyword.

Runs entirely in your browser — your input is never uploaded, stored, or logged.

Search any HTTP status code by number or keyword to get a quick, accurate description. For looking up MIME types to return in your HTTP responses, see the MIME Type Reference.

Examples

Common codes

Input

Output

404 Not Found — The server cannot find the requested resource.

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