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HTTP Status Code Reference

Every HTTP status code you need to know, grouped by category, with plain-English descriptions. Searchable by code, name, or keyword.

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1xx Informational

  • 100
    Continue
    RFC 9110
    Client should continue with the request. Response to an Expect: 100-continue header.
  • 101
    Switching Protocols
    RFC 9110
    Server is switching protocols as requested by the client (e.g., HTTP/2, WebSocket).
  • 102
    Processing
    WebDAV: server has received and is processing the request, no response available yet.
  • 103
    Early Hints
    Used to return some response headers before the final HTTP message, useful for preloading resources.

2xx Success

  • 200
    OK
    RFC 9110
    The request succeeded.
  • 201
    Created
    RFC 9110
    The request succeeded and a new resource was created.
  • 202
    Accepted
    RFC 9110
    The request has been accepted for processing, but processing has not completed.
  • 204
    No Content
    RFC 9110
    The request succeeded but there is no content to send back.
  • 206
    Partial Content
    RFC 9110
    Server delivered partial content because of a Range header (e.g., video seeking).

3xx Redirection

  • 301
    Moved Permanently
    RFC 9110
    The URL of the requested resource has been changed permanently. New URL given in Location.
  • 302
    Found
    RFC 9110
    Temporary redirect. The resource is temporarily at a different URL.
  • 303
    See Other
    RFC 9110
    Client should GET the URL in Location. Often used after PUT/POST.
  • 304
    Not Modified
    RFC 9110
    The cached copy is still valid; use it. Response to conditional GET.
  • 307
    Temporary Redirect
    RFC 9110
    Like 302 but the method (GET/POST/etc.) must not change.
  • 308
    Permanent Redirect
    RFC 9110
    Like 301 but the method must not change.

4xx Client Error

  • 400
    Bad Request
    RFC 9110
    The server cannot process the request due to a client error (malformed syntax, invalid framing).
  • 401
    Unauthorized
    RFC 9110
    Authentication is required and has failed or has not been provided.
  • 402
    Payment Required
    Reserved for future use, sometimes used for paywall responses.
  • 403
    Forbidden
    RFC 9110
    The request was valid but the server refuses to authorize it. Authentication will not help.
  • 404
    Not Found
    RFC 9110
    The requested resource could not be found on the server.
  • 405
    Method Not Allowed
    RFC 9110
    The HTTP method is not supported for this resource (e.g., POST to a read-only endpoint).
  • 406
    Not Acceptable
    RFC 9110
    The server cannot produce a response matching the Accept headers.
  • 408
    Request Timeout
    RFC 9110
    The server timed out waiting for the request.
  • 409
    Conflict
    RFC 9110
    The request conflicts with the current state (e.g., edit conflict, duplicate key).
  • 410
    Gone
    RFC 9110
    The resource has been permanently removed and will not be available again.
  • 411
    Length Required
    The request did not specify Content-Length, which the server requires.
  • 413
    Payload Too Large
    RFC 9110
    The request body is larger than the server is willing to process.
  • 414
    URI Too Long
    RFC 9110
    The URI is longer than the server is willing to interpret.
  • 415
    Unsupported Media Type
    RFC 9110
    The media format of the request is not supported.
  • 418
    I'm a Teapot
    RFC 2324
    April Fools joke from RFC 2324 — the server refuses to brew coffee because it is a teapot.
  • 422
    Unprocessable Content
    RFC 9110
    The request was syntactically correct but semantically invalid (common in REST APIs for validation errors).
  • 425
    Too Early
    The server is unwilling to risk processing a request that might be replayed.
  • 428
    Precondition Required
    Origin server requires the request to be conditional (e.g., If-Match header) to prevent lost updates.
  • 429
    Too Many Requests
    Rate limit exceeded. Check Retry-After header.
  • 451
    Unavailable For Legal Reasons
    Resource is unavailable due to legal demands (censorship, court order).

5xx Server Error

  • 500
    Internal Server Error
    RFC 9110
    The server encountered an unexpected condition.
  • 501
    Not Implemented
    RFC 9110
    The server does not support the functionality required.
  • 502
    Bad Gateway
    RFC 9110
    The server, acting as a gateway, received an invalid response from the upstream server.
  • 503
    Service Unavailable
    RFC 9110
    The server is not ready to handle the request (overloaded, down for maintenance).
  • 504
    Gateway Timeout
    RFC 9110
    Gateway server did not get a response from the upstream server in time.
  • 507
    Insufficient Storage
    The server is unable to store the representation needed to complete the request.
  • 508
    Loop Detected
    The server detected an infinite loop while processing a WebDAV request.
  • 511
    Network Authentication Required
    The client needs to authenticate to gain network access (typical of captive portals).

Frequently asked

Which spec are these from?

RFC 9110 (2022, the current HTTP semantics spec) plus IANA registrations. WebDAV codes (102, 207, 507, 508) are included.

What is the difference between 401 and 403?

401 means you have not authenticated (missing or bad credentials). 403 means you are authenticated but do not have permission for this resource.

Is 418 real?

Yes, technically — RFC 2324 defined it as an April Fools joke in 1998. It has never been deprecated and is a fine easter egg for teapot-shaped endpoints.

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