Complete HTTP reference

HTTP Status Codes

Every status code, grouped by class. Click any code for a full explanation with examples and common causes.

1xx informational response

100Continue 101Switching Protocols 102Processing 103Early Hints

2xx success

200OK 201Created 202Accepted 203Non-Authoritative Information 204No Content 205Reset Content 206Partial Content 207Multi-Status 208Already Reported 226IM Used

3xx redirection

300Multiple Choices 301Moved Permanently 302Found 303See Other 304Not Modified 305Use Proxy 306Switch Proxy 307Temporary Redirect 308Permanent Redirect

4xx client error

400Bad Request 401Unauthorized 402Payment Required 403Forbidden 404Not Found 405Method Not Allowed 406Not Acceptable 407Proxy Authentication Required 408Request Timeout 409Conflict 410Gone 411Length Required 412Precondition Failed 413Payload Too Large 414URI Too Long 415Unsupported Media Type 416Range Not Satisfiable 417Expectation Failed 418I'm a teapot 421Misdirected Request 422Unprocessable Entity 423Locked 424Failed Dependency 425Too Early 426Upgrade Required 428Precondition Required 429Too Many Requests 431Request Header Fields Too Large 451Unavailable For Legal Reasons

5xx server error

500Internal Server Error 501Not Implemented 502Bad Gateway 503Service Unavailable 504Gateway Timeout 505HTTP Version Not Supported 506Variant Also Negotiates 507Insufficient Storage 508Loop Detected 510Not Extended 511Network Authentication Required

How HTTP status codes work

Every HTTP response begins with a three-digit status code whose first digit defines its class. 1xx is informational, 2xx means success, 3xx means a redirect or further action is needed, 4xx means the request was faulty (the client’s fault, like 404 or 403), and 5xx means the server failed while handling a valid request (like 500). Understanding these is fundamental to debugging web apps, configuring redirects and building reliable APIs.