Continue
The server has received the request headers and the client should proceed to send the request body.
Common Use
Used with Expect: 100-continue header
Switching Protocols
The requester has asked the server to switch protocols and the server has agreed to do so.
Common Use
WebSocket upgrades
Processing
A WebDAV request may contain many sub-requests involving file operations, requiring a long time to complete.
Common Use
WebDAV operations
Early Hints
Used to return some response headers before final HTTP message.
Common Use
Performance optimization
OK
Standard response for successful HTTP requests.
Example
GET /users → Returns user listCommon Use
Most common success response
Created
The request has been fulfilled, resulting in the creation of a new resource.
Example
POST /users → User createdCommon Use
Resource creation via POST/PUT
Accepted
The request has been accepted for processing, but the processing has not been completed.
Common Use
Asynchronous processing
Non-Authoritative Information
The server is a transforming proxy that received a 200 OK but is returning a modified version.
Common Use
Proxy transformations
No Content
The server successfully processed the request and is not returning any content.
Example
DELETE /users/123 → User deletedCommon Use
DELETE operations, updates without response body
Reset Content
The server successfully processed the request, but is not returning any content and requires the requester to reset the document view.
Common Use
Form submissions requiring reset
Partial Content
The server is delivering only part of the resource due to a range header sent by the client.
Common Use
Video streaming, file downloads
Multiple Choices
Indicates multiple options for the resource from which the client may choose.
Common Use
Content negotiation
Moved Permanently
This and all future requests should be directed to the given URI.
Example
Location: https://newsite.comCommon Use
SEO-friendly redirects, site migrations
Found
Tells the client to look at another URL. A temporary redirect.
Common Use
Temporary redirects, after form submission
See Other
The response to the request can be found under another URI using a GET method.
Common Use
POST-redirect-GET pattern
Not Modified
Indicates that the resource has not been modified since the version specified by the request headers.
Common Use
Browser caching, ETags
Temporary Redirect
The request should be repeated with another URI, but future requests should still use the original URI.
Common Use
Temporary redirects preserving method
Permanent Redirect
The request and all future requests should be repeated using another URI.
Common Use
Permanent redirects preserving method
Bad Request
The server cannot or will not process the request due to an apparent client error.
Example
Invalid JSON in request bodyCommon Use
Malformed requests, validation errors
Unauthorized
Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided.
Example
WWW-Authenticate: BearerCommon Use
Missing or invalid authentication
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.
Common Use
Payment gateways, subscription services
Forbidden
The request was valid, but the server is refusing action. The user might not have the necessary permissions.
Example
Access denied to admin panelCommon Use
Authorization failures, insufficient permissions
Not Found
The requested resource could not be found but may be available in the future.
Example
GET /users/999 → User not foundCommon Use
Most common error, missing resources
Method Not Allowed
A request method is not supported for the requested resource.
Example
POST to GET-only endpointCommon Use
Wrong HTTP method used
Not Acceptable
The requested resource is capable of generating only content not acceptable according to the Accept headers.
Common Use
Content negotiation failures
Proxy Authentication Required
The client must first authenticate itself with the proxy.
Common Use
Corporate proxy authentication
Request Timeout
The server timed out waiting for the request.
Common Use
Slow client connections
Conflict
Indicates that the request could not be processed because of conflict in the request.
Example
Username already existsCommon Use
Resource conflicts, version conflicts
Gone
Indicates that the resource requested is no longer available and will not be available again.
Common Use
Permanently deleted resources
Length Required
The request did not specify the length of its content, which is required by the requested resource.
Common Use
Missing Content-Length header
Precondition Failed
The server does not meet one of the preconditions that the requester put on the request.
Common Use
Conditional requests with ETags
Payload Too Large
The request is larger than the server is willing or able to process.
Common Use
File upload size limits
URI Too Long
The URI provided was too long for the server to process.
Common Use
Extremely long URLs
Unsupported Media Type
The request entity has a media type which the server or resource does not support.
Example
Sending XML to JSON-only APICommon Use
Wrong Content-Type header
Range Not Satisfiable
The client has asked for a portion of the file, but the server cannot supply that portion.
Common Use
Invalid byte ranges
Expectation Failed
The server cannot meet the requirements of the Expect request-header field.
Common Use
Expect: 100-continue failures
I'm a teapot
This code was defined in 1998 as one of the traditional IETF April Fools' jokes.
Common Use
April Fools joke, Easter egg
Misdirected Request
The request was directed at a server that is not able to produce a response.
Common Use
HTTP/2 connection reuse issues
Unprocessable Entity
The request was well-formed but was unable to be followed due to semantic errors.
Example
Validation errors in form dataCommon Use
WebDAV, form validation errors
Locked
The resource that is being accessed is locked.
Common Use
WebDAV resource locking
Failed Dependency
The request failed due to failure of a previous request.
Common Use
WebDAV batch operations
Too Early
Indicates that the server is unwilling to risk processing a request that might be replayed.
Common Use
TLS 1.3 early data protection
Upgrade Required
The client should switch to a different protocol such as TLS/1.0.
Common Use
Force HTTPS upgrades
Precondition Required
The origin server requires the request to be conditional.
Common Use
Lost update prevention
Too Many Requests
The user has sent too many requests in a given amount of time.
Example
Retry-After: 3600Common Use
Rate limiting, API throttling
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.
Common Use
Large cookie headers
Unavailable For Legal Reasons
A server operator has received a legal demand to deny access to a resource or to a set of resources.
Common Use
Content blocking, censorship
Internal Server Error
A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.
Example
Unhandled exception in codeCommon Use
Most common server error
Not Implemented
The server either does not recognize the request method, or it lacks the ability to fulfill the request.
Common Use
Unsupported HTTP methods
Bad Gateway
The server was acting as a gateway or proxy and received an invalid response from the upstream server.
Common Use
Proxy/load balancer errors
Service Unavailable
The server is currently unavailable (because it is overloaded or down for maintenance).
Example
Retry-After: 120Common Use
Maintenance mode, overload
Gateway Timeout
The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.
Common Use
Upstream timeouts
HTTP Version Not Supported
The server does not support the HTTP protocol version used in the request.
Common Use
Old HTTP versions
Variant Also Negotiates
Transparent content negotiation for the request results in a circular reference.
Common Use
Content negotiation errors
Insufficient Storage
The server is unable to store the representation needed to complete the request.
Common Use
WebDAV storage limits
Loop Detected
The server detected an infinite loop while processing the request.
Common Use
WebDAV binding loops
Not Extended
Further extensions to the request are required for the server to fulfill it.
Common Use
HTTP extension framework
Network Authentication Required
The client needs to authenticate to gain network access.
Common Use
Captive portals, hotel WiFi