HTTP Status Code Reference
HTTP status code reference
HTTP status codes come in five classes by first digit: 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors. Search any code or keyword below — like 404, redirect, or rate limit — for its plain-English meaning.
Frequently asked questions
What does 404 mean?
404 Not Found — the server was reached but there's no resource at that URL. A 4xx client status, often a wrong or outdated link.
301 vs 302 redirect?
301 is permanent (search engines pass ranking to the new URL); 302 is temporary (they keep the original indexed). Use 301 for permanent moves.
What are the five classes?
1xx informational, 2xx success, 3xx redirection, 4xx client errors, 5xx server errors — the first digit is the category.