HTTP Status Codes

AllInformationalSuccessRedirectionClient ErrorServer Error

Informational (4)

100 Continue

The initial part of a request has been received and has not yet been rejected by the server.

Reference: RFC 9110
Example usage:
Used with Expect: 100-continue header
Informational
101 Switching Protocols

The server understands and is willing to comply with the client's request to switch protocols.

Reference: RFC 9110
Example usage:
WebSocket upgrade requests
Informational
102 Processing

The server has received and is processing the request, but no response is available yet.

Reference: RFC 2518
Example usage:
WebDAV extended operations
Informational
103 Early Hints

Used to return some response headers before final HTTP message.

Reference: RFC 8297
Example usage:
Link preload headers
Informational

Success (10)

200 OK

The request has succeeded.

Reference: RFC 9110
Example usage:
Standard response for successful HTTP requests
Success
201 Created

The request has been fulfilled and resulted in a new resource being created.

Reference: RFC 9110
Example usage:
POST request successfully created a resource
Success
202 Accepted

The request has been accepted for processing, but the processing has not been completed.

Reference: RFC 9110
Example usage:
Asynchronous processing requests
Success
203 Non-Authoritative Information

The request was successful but the enclosed payload has been modified from the origin server's 200 OK response.

Reference: RFC 9110
Example usage:
Proxy modified the response
Success
204 No Content

The server successfully processed the request and is not returning any content.

Reference: RFC 9110
Example usage:
DELETE request successful
Success
205 Reset Content

The server successfully processed the request, but is not returning any content and requires that the requester reset the document view.

Reference: RFC 9110
Example usage:
Form submission successful, clear form
Success
206 Partial Content

The server is delivering only part of the resource due to a range header sent by the client.

Reference: RFC 9110
Example usage:
Video streaming, file downloads with resume
Success
207 Multi-Status

The message body contains multiple separate response codes.

Reference: RFC 4918
Example usage:
WebDAV batch operations
Success
208 Already Reported

The members of a DAV binding have already been enumerated in a previous reply to this request.

Reference: RFC 5842
Example usage:
WebDAV binding collections
Success
226 IM Used

The server has fulfilled a request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.

Reference: RFC 3229
Example usage:
Delta encoding in HTTP
Success

Redirection (8)

300 Multiple Choices

Indicates multiple options for the resource from which the client may choose.

Reference: RFC 9110
Example usage:
Multiple file formats available
Redirection
301 Moved Permanently

This and all future requests should be directed to the given URI.

Reference: RFC 9110
Example usage:
Domain name changes, URL restructuring
Redirection
302 Found

Tells the client to look at another URL temporarily.

Reference: RFC 9110
Example usage:
Temporary redirects, user authentication flows
Redirection
303 See Other

The response to the request can be found under another URI using the GET method.

Reference: RFC 9110
Example usage:
POST-redirect-GET pattern
Redirection
304 Not Modified

Indicates that the resource has not been modified since the version specified by the request headers.

Reference: RFC 9110
Example usage:
Browser caching, conditional requests
Redirection
305 Use Proxy

The requested resource is available only through a proxy.

Reference: RFC 9110
Example usage:
Deprecated - security concerns
Redirection
307 Temporary Redirect

The request should be repeated with another URI; however, future requests should still use the original URI.

Reference: RFC 9110
Example usage:
Server maintenance, load balancing
Redirection
308 Permanent Redirect

The request and all future requests should be repeated using another URI.

Reference: RFC 7538
Example usage:
HTTPS enforcement, URL changes
Redirection

Client Error (29)

400 Bad Request

The server cannot or will not process the request due to an apparent client error.

Reference: RFC 9110
Example usage:
Malformed request syntax, invalid parameters
Client Error
401 Unauthorized

Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided.

Reference: RFC 9110
Example usage:
Missing or invalid authentication credentials
Client Error
402 Payment Required

Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme.

Reference: RFC 9110
Example usage:
Digital payment systems (rarely used)
Client Error
403 Forbidden

The request contained valid data and was understood by the server, but the server is refusing action.

Reference: RFC 9110
Example usage:
Insufficient permissions, IP blocking
Client Error
404 Not Found

The requested resource could not be found but may be available in the future.

Reference: RFC 9110
Example usage:
Broken links, deleted resources, typos in URL
Client Error
405 Method Not Allowed

A request method is not supported for the requested resource.

Reference: RFC 9110
Example usage:
Using POST on a GET-only endpoint
Client Error
406 Not Acceptable

The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request.

Reference: RFC 9110
Example usage:
Client requests XML but server only has JSON
Client Error
407 Proxy Authentication Required

The client must first authenticate itself with the proxy.

Reference: RFC 9110
Example usage:
Corporate proxy requiring authentication
Client Error
408 Request Timeout

The server timed out waiting for the request.

Reference: RFC 9110
Example usage:
Client took too long to send request
Client Error
409 Conflict

Indicates that the request could not be processed because of conflict in the current state of the resource.

Reference: RFC 9110
Example usage:
Version conflicts, duplicate resource creation
Client Error
410 Gone

Indicates that the resource requested is no longer available and will not be available again.

Reference: RFC 9110
Example usage:
Permanently deleted resources
Client Error
411 Length Required

The request did not specify the length of its content, which is required by the requested resource.

Reference: RFC 9110
Example usage:
Missing Content-Length header
Client Error
412 Precondition Failed

The server does not meet one of the preconditions that the requester put on the request header fields.

Reference: RFC 9110
Example usage:
If-Match header conditions not met
Client Error
413 Content Too Large

The request is larger than the server is willing or able to process.

Reference: RFC 9110
Example usage:
File upload exceeds size limit
Client Error
414 URI Too Long

The URI provided was too long for the server to process.

Reference: RFC 9110
Example usage:
URL with too many query parameters
Client Error
415 Unsupported Media Type

The request entity has a media type which the server or resource does not support.

Reference: RFC 9110
Example usage:
Uploading unsupported file format
Client Error
416 Range Not Satisfiable

The client has asked for a portion of the file, but the server cannot supply that portion.

Reference: RFC 9110
Example usage:
Invalid byte range in Range header
Client Error
417 Expectation Failed

The server cannot meet the requirements of the Expect request-header field.

Reference: RFC 9110
Example usage:
Expect: 100-continue not supported
Client Error
418 I'm a teapot

This code was defined in 1998 as one of the traditional IETF April Fools' jokes.

Reference: RFC 2324
Example usage:
April Fools' joke, some services use it humorously
Client Error
421 Misdirected Request

The request was directed at a server that is not able to produce a response.

Reference: RFC 9110
Example usage:
HTTP/2 connection reuse issues
Client Error
422 Unprocessable Content

The request was well-formed but was unable to be followed due to semantic errors.

Reference: RFC 4918
Example usage:
Validation errors in request body
Client Error
423 Locked

The resource that is being accessed is locked.

Reference: RFC 4918
Example usage:
WebDAV locked resources
Client Error
424 Failed Dependency

The request failed because it depended on another request and that request failed.

Reference: RFC 4918
Example usage:
WebDAV dependent operations
Client Error
425 Too Early

Indicates that the server is unwilling to risk processing a request that might be replayed.

Reference: RFC 8470
Example usage:
TLS early data concerns
Client Error
426 Upgrade Required

The client should switch to a different protocol such as TLS/1.3.

Reference: RFC 9110
Example usage:
HTTP to HTTPS upgrade requirement
Client Error
428 Precondition Required

The origin server requires the request to be conditional.

Reference: RFC 6585
Example usage:
Prevent lost update problem
Client Error
429 Too Many Requests

The user has sent too many requests in a given amount of time.

Reference: RFC 6585
Example usage:
Rate limiting, API quotas exceeded
Client Error
431 Request Header Fields Too Large

The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.

Reference: RFC 6585
Example usage:
Cookie header too large
Client Error
451 Unavailable For Legal Reasons

A server operator has received a legal demand to deny access to a resource or to a set of resources.

Reference: RFC 7725
Example usage:
Content blocked due to legal requirements
Client Error

Server Error (11)

500 Internal Server Error

A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.

Reference: RFC 9110
Example usage:
Unhandled exceptions, server crashes
Server Error
501 Not Implemented

The server either does not recognize the request method, or it lacks the ability to fulfil the request.

Reference: RFC 9110
Example usage:
Unsupported HTTP methods
Server Error
502 Bad Gateway

The server was acting as a gateway or proxy and received an invalid response from the upstream server.

Reference: RFC 9110
Example usage:
Proxy/load balancer upstream errors
Server Error
503 Service Unavailable

The server cannot handle the request because it is overloaded or down for maintenance.

Reference: RFC 9110
Example usage:
Server maintenance, overload
Server Error
504 Gateway Timeout

The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.

Reference: RFC 9110
Example usage:
Upstream server timeout
Server Error
505 HTTP Version Not Supported

The server does not support the HTTP protocol version used in the request.

Reference: RFC 9110
Example usage:
Client using unsupported HTTP version
Server Error
506 Variant Also Negotiates

Transparent content negotiation for the request results in a circular reference.

Reference: RFC 2295
Example usage:
Content negotiation configuration error
Server Error
507 Insufficient Storage

The server is unable to store the representation needed to complete the request.

Reference: RFC 4918
Example usage:
WebDAV server storage full
Server Error
508 Loop Detected

The server detected an infinite loop while processing the request.

Reference: RFC 5842
Example usage:
WebDAV binding loops
Server Error
510 Not Extended

Further extensions to the request are required for the server to fulfil it.

Reference: RFC 2774
Example usage:
HTTP Extension Framework
Server Error
511 Network Authentication Required

The client needs to authenticate to gain network access.

Reference: RFC 6585
Example usage:
Captive portal authentication
Server Error

HTTP status code data sourced from official IETF RFCs and standards.

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