HTTP Status Codes — Complete 1xx to 5xx Reference
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Complete reference for all HTTP status codes organized by class: 1xx Informational (100–103), 2xx Success (200–206), 3xx Redirection (301–308), 4xx Client Error (400–429), and 5xx Server Error (500–511). Each code includes its official RFC reference, plain-English description, retryability, and cacheability.
Click any status code to see full details, code snippets, and usage guide
Frequently Asked Questions
How many HTTP status codes are there?
The IANA HTTP Status Code Registry lists over 70 official codes. The most commonly used in REST APIs are about 15–20 codes. This reference covers all major codes including the latest additions from RFC 9110 (2022) which supersedes RFC 7231.
What is the newest HTTP status code?
103 Early Hints (RFC 8297, 2017) is one of the newer additions. It allows servers to send preliminary Link headers before the final response, enabling browsers to preload critical resources. Used at CDN/reverse proxy layer to improve page load performance.
What are the 5 classes of HTTP status codes?
1xx Informational — request received, continuing process. 2xx Success — request was successfully received, understood, and accepted. 3xx Redirection — further action must be taken to complete the request. 4xx Client Error — request contains bad syntax or cannot be fulfilled. 5xx Server Error — server failed to fulfill an apparently valid request.
Are HTTP status codes case-sensitive?
The numeric code is not case-sensitive (it's a number). The reason phrase (e.g., "Not Found", "OK") is informational only — HTTP/2 and HTTP/3 do not even include reason phrases. Your code should always check the numeric status code, not the reason string.
What HTTP codes are cacheable by default?
Per RFC 9110, these codes are cacheable without explicit Cache-Control headers: 200 OK, 203 Non-Authoritative, 204 No Content, 206 Partial Content, 300 Multiple Choices, 301 Moved Permanently, 308 Permanent Redirect, 404 Not Found, 405 Method Not Allowed, 410 Gone, 414 URI Too Long, 501 Not Implemented.
What is a retryable HTTP status code?
Retryable codes indicate the client may send the same request again after a delay: 408 Request Timeout, 429 Too Many Requests (after Retry-After), 500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable, 504 Gateway Timeout. Non-retryable codes like 400, 401, 403, 404, 422 indicate the request itself must be fixed before retrying.