HTTP Status Codes
A complete, searchable reference of HTTP response status codes from 1xx through 5xx, including WebDAV extensions and the CDN-specific 52x family. Each entry explains what the code really signals and when you should use it.
| Code | Name | Category | Meaning |
|---|---|---|---|
| 100 | Continue | 1xx Informational | The client should continue with its request. Sent in response to an Expect: 100-continue header. |
| 101 | Switching Protocols | 1xx Informational | The server is switching protocols as requested — used to upgrade an HTTP connection to WebSocket. |
| 102 | Processing | 1xx Informational | WebDAV. The server has accepted the request but has not completed it yet. |
| 103 | Early Hints | 1xx Informational | Sends Link headers early so the browser can preload assets before the final response arrives. |
| 200 | OK | 2xx Success | The request succeeded. The meaning depends on the method: GET returns the resource, POST returns the result. |
| 201 | Created | 2xx Success | The request succeeded and a new resource was created. The Location header points to it. |
| 202 | Accepted | 2xx Success | The request was accepted for processing but is not complete. Common for asynchronous jobs. |
| 203 | Non-Authoritative Information | 2xx Success | The response was modified by a proxy and may differ from the origin. |
| 204 | No Content | 2xx Success | Success, but there is no body to return. Often used for DELETE and for form submissions that should not navigate. |
| 205 | Reset Content | 2xx Success | Success. The client should reset the document view, for example clear a form. |
| 206 | Partial Content | 2xx Success | Only part of the resource was sent, in response to a Range header. Used for resumable downloads and video seeking. |
| 207 | Multi-Status | 2xx Success | WebDAV. The body contains separate status codes for multiple sub-requests. |
| 208 | Already Reported | 2xx Success | WebDAV. Members of a binding have already been enumerated. |
| 226 | IM Used | 2xx Success | The server applied delta encoding to the response. |
| 300 | Multiple Choices | 3xx Redirect | The request has more than one possible response. The client should choose. |
| 301 | Moved Permanently | 3xx Redirect | The resource has permanently moved. Search engines transfer ranking to the new URL. Browsers cache this aggressively. |
| 302 | Found | 3xx Redirect | Temporary redirect. The original URL keeps its ranking. The method may be changed to GET by some clients. |
| 303 | See Other | 3xx Redirect | Fetch the new URL with GET. Used after a POST to avoid resubmission on refresh. |
| 304 | Not Modified | 3xx Redirect | The cached copy is still valid, so no body is sent. Triggered by If-None-Match or If-Modified-Since. |
| 305 | Use Proxy | 3xx Redirect | Deprecated. The resource must be accessed through a proxy. |
| 307 | Temporary Redirect | 3xx Redirect | Like 302 but the HTTP method and body must not be changed. |
| 308 | Permanent Redirect | 3xx Redirect | Like 301 but the HTTP method and body must not be changed. |
| 400 | Bad Request | 4xx Client Error | The server could not understand the request — malformed syntax, invalid framing or a deceptive request. |
| 401 | Unauthorized | 4xx Client Error | Authentication is required or has failed. Despite the name this means unauthenticated, not unauthorised. |
| 402 | Payment Required | 4xx Client Error | Reserved for future use. Occasionally used by APIs to signal quota exhaustion. |
| 403 | Forbidden | 4xx Client Error | The server understood the request but refuses it. Unlike 401, authenticating will not help. |
| 404 | Not Found | 4xx Client Error | The server cannot find the resource. The most common error on the web — it does not say whether the resource ever existed. |
| 405 | Method Not Allowed | 4xx Client Error | The method is known but not supported for this resource. The Allow header lists what is permitted. |
| 406 | Not Acceptable | 4xx Client Error | No representation matches the Accept headers sent by the client. |
| 407 | Proxy Authentication Required | 4xx Client Error | Like 401 but authentication must be done with the proxy. |
| 408 | Request Timeout | 4xx Client Error | The server timed out waiting for the request. Often sent on idle keep-alive connections. |
| 409 | Conflict | 4xx Client Error | The request conflicts with the current state, for example an edit based on a stale version. |
| 410 | Gone | 4xx Client Error | The resource is permanently gone with no forwarding address. Stronger than 404 and removes it from search indexes faster. |
| 411 | Length Required | 4xx Client Error | The server requires a Content-Length header. |
| 412 | Precondition Failed | 4xx Client Error | A condition in the request headers (such as If-Match) evaluated to false. |
| 413 | Content Too Large | 4xx Client Error | The request body is larger than the server will accept. Previously "Payload Too Large". |
| 414 | URI Too Long | 4xx Client Error | The requested URL is longer than the server will interpret. |
| 415 | Unsupported Media Type | 4xx Client Error | The body format is not supported — usually a wrong or missing Content-Type. |
| 416 | Range Not Satisfiable | 4xx Client Error | The Range header asks for a portion that does not exist. |
| 417 | Expectation Failed | 4xx Client Error | The expectation in the Expect header could not be met. |
| 418 | I'm a teapot | 4xx Client Error | An April Fools joke from RFC 2324 that became a real convention. Some servers use it to reject automated traffic. |
| 421 | Misdirected Request | 4xx Client Error | The request was sent to a server that cannot produce a response for this authority. Common with HTTP/2 connection reuse. |
| 422 | Unprocessable Content | 4xx Client Error | The syntax is correct but the content is semantically invalid. Widely used by APIs for validation failures. |
| 423 | Locked | 4xx Client Error | WebDAV. The resource is locked. |
| 424 | Failed Dependency | 4xx Client Error | WebDAV. The request failed because a previous request failed. |
| 425 | Too Early | 4xx Client Error | The server will not risk processing a request that might be replayed. |
| 426 | Upgrade Required | 4xx Client Error | The client must switch protocols, listed in the Upgrade header. |
| 428 | Precondition Required | 4xx Client Error | The server requires a conditional request to prevent lost updates. |
| 429 | Too Many Requests | 4xx Client Error | The client has sent too many requests. Check the Retry-After header before retrying. |
| 431 | Request Header Fields Too Large | 4xx Client Error | The headers are too large — often an oversized cookie. |
| 451 | Unavailable For Legal Reasons | 4xx Client Error | Access denied for legal reasons such as censorship or a takedown. The number references Fahrenheit 451. |
| 500 | Internal Server Error | 5xx Server Error | A generic server failure with no more specific message. Check the server logs. |
| 501 | Not Implemented | 5xx Server Error | The server does not support the functionality required to fulfil the request. |
| 502 | Bad Gateway | 5xx Server Error | A gateway or proxy got an invalid response from the upstream server. |
| 503 | Service Unavailable | 5xx Server Error | The server is temporarily overloaded or down for maintenance. Should include Retry-After. |
| 504 | Gateway Timeout | 5xx Server Error | A gateway or proxy did not get a response from upstream in time. |
| 505 | HTTP Version Not Supported | 5xx Server Error | The HTTP version used in the request is not supported. |
| 506 | Variant Also Negotiates | 5xx Server Error | A content negotiation configuration error on the server. |
| 507 | Insufficient Storage | 5xx Server Error | WebDAV. Not enough storage to complete the request. |
| 508 | Loop Detected | 5xx Server Error | WebDAV. An infinite loop was detected while processing the request. |
| 510 | Not Extended | 5xx Server Error | Further extensions are required for the server to fulfil the request. |
| 511 | Network Authentication Required | 5xx Server Error | The client must authenticate to gain network access. Used by captive portals. |
| 520 | Unknown Error (CDN) | 5xx Server Error | CDN-specific. The origin returned something the edge could not interpret. |
| 521 | Web Server Is Down (CDN) | 5xx Server Error | CDN-specific. The origin refused the connection. |
| 522 | Connection Timed Out (CDN) | 5xx Server Error | CDN-specific. The TCP handshake with the origin did not complete. |
| 523 | Origin Is Unreachable (CDN) | 5xx Server Error | CDN-specific. The origin could not be routed to — often a DNS or firewall problem. |
| 524 | A Timeout Occurred (CDN) | 5xx Server Error | CDN-specific. The connection succeeded but the origin did not answer in time. |
| 525 | SSL Handshake Failed (CDN) | 5xx Server Error | CDN-specific. The TLS handshake with the origin failed — usually a certificate or cipher mismatch. |
| 526 | Invalid SSL Certificate (CDN) | 5xx Server Error | CDN-specific. The origin certificate could not be validated. |
About this reference
A complete, searchable reference of HTTP response status codes from 1xx through 5xx, including WebDAV extensions and the CDN-specific 52x family. Each entry explains what the code really signals and when you should use it.
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