What is HTTP Status Codes?
HTTP status codes are three-digit responses that indicate the result of a request: 1xx informational, 2xx success, 3xx redirection, 4xx client errors and 5xx server errors. Knowing them is essential for debugging APIs and understanding what a server responds.
This quick reference gathers the most frequent codes with their name and meaning, from the familiar 404 (not found) to 429 (too many requests) or 502 (bad gateway). Use it to interpret any service's response at a glance.
The most looked-up ones: 200 (OK), 301/302 (permanent/temporary redirect), 401 (authentication required) versus 403 (authenticated but no permission), 404 (not found), 429 (too many requests) and 500/502/503 (server errors). When debugging an API, pair it with our HTTP headers inspector.
Frequently asked questions
What does error 404 mean?
Not Found: the server could not find the requested resource at that URL.
What about error 500?
Internal Server Error: a generic server-side failure while processing the request.
What is the difference between 301 and 302?
301 is a permanent redirect (passes SEO to the destination); 302 is temporary (the origin stays canonical).
What do the 2xx, 4xx and 5xx ranges mean?
2xx = success, 3xx = redirection, 4xx = client error and 5xx = server error.
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