100 Continue
The server has received the request headers and the client should proceed to send the request body.
101 Switching Protocols
The server is switching protocols as requested by the client — typically HTTP to WebSocket.
102 Processing
The server has received and is processing the request, but no response is available yet (WebDAV).
103 Early Hints
Returns some response headers before the final response to allow the client to start preloading resources.
200 OK • Common
The request was successful. The response body contains the requested data.
201 Created • Common
The request was successful and a new resource was created. The Location header typically points to the new resource.
202 Accepted
The request was accepted for processing but processing has not been completed — it may not be completed.
203 Non-Authoritative Information
The response is from a proxy that modified the original server's 200 response.
204 No Content • Common
The request was successful but there is no content to return. Used for DELETE or updates.
205 Reset Content
The server processed the request and the client should reset the document view (e.g., clear a form).
206 Partial Content • Common
The server is delivering a portion of the resource (partial response) due to a Range request header.
207 Multi-Status
Contains information about multiple resources in situations where multiple status codes might be appropriate (WebDAV).
208 Already Reported
The members of a DAV binding have already been enumerated in a previous reply and are not included again.
226 IM Used
The server fulfilled a GET request for the resource and the response is a representation of the result of one or more instance-manipulations.
300 Multiple Choices
The request has multiple possible responses. The client should choose one.
301 Moved Permanently • Common
The resource has permanently moved to a new URL. Clients and search engines should update their bookmarks.
302 Found (Temporary Redirect) • Common
The resource is temporarily at a different URL. Clients should continue using the original URL in the future.
303 See Other
The response to the request can be found at a different URL using a GET request (PRG pattern).
304 Not Modified • Common
The resource has not been modified since the version specified in the request headers. Use cached version.
307 Temporary Redirect • Common
Same as 302 but explicitly requires the same HTTP method to be used on the redirect.
308 Permanent Redirect
Same as 301 but explicitly requires the same HTTP method to be used on the redirect.
400 Bad Request • Common
The server cannot process the request due to malformed syntax, invalid parameters, or missing required data.
401 Unauthorized • Common
The request requires authentication. The client must provide valid credentials.
402 Payment Required
Reserved for future use. Some APIs use it to indicate payment is needed.
403 Forbidden • Common
The server understood the request but refuses to authorize it. Authentication won't help.
404 Not Found • Common
The server cannot find the requested resource. The URL may be wrong or the resource deleted.
405 Method Not Allowed • Common
The HTTP method used is not allowed for this endpoint.
406 Not Acceptable
The server cannot produce a response matching the Accept headers sent by the client.
407 Proxy Authentication Required
The client must authenticate with a proxy before proceeding.
408 Request Timeout
The server timed out waiting for the request to complete.
409 Conflict • Common
The request conflicts with the current state of the server (e.g., duplicate resource, version conflict).
410 Gone
The resource was permanently deleted and will not be available again. Unlike 404, this is intentional.
411 Length Required
The server requires a Content-Length header for this request.
412 Precondition Failed
A precondition in the request headers was not met (e.g., If-Match or If-Unmodified-Since).
413 Content Too Large • Common
The request body is larger than the server is willing to process.
414 URI Too Long
The URL is longer than the server can process.
415 Unsupported Media Type • Common
The server does not support the Content-Type of the request body.
416 Range Not Satisfiable
The Range header cannot be fulfilled — the range is outside the resource size.
417 Expectation Failed
The server cannot meet the requirements of the Expect request header.
418 I'm a Teapot
An April Fools' joke from RFC 2324 (Hyper Text Coffee Pot Control Protocol). Some servers use it for joke responses or to block bots.
422 Unprocessable Content • Common
The request was well-formed but failed semantic validation. Often returned with validation errors.
423 Locked
The resource is locked (WebDAV). Another operation has the resource locked.
424 Failed Dependency
The request failed because it depended on another request that failed (WebDAV).
425 Too Early
The server is unwilling to process a request that might be replayed (TLS 0-RTT anti-replay).
426 Upgrade Required
The server requires the client to upgrade to a different protocol.
428 Precondition Required
The server requires the request to be conditional (use If-Match or similar headers).
429 Too Many Requests • Common
The client has sent too many requests in a given time period (rate limiting).
431 Request Header Fields Too Large
The server is not willing to process the request because its header fields are too large.
451 Unavailable For Legal Reasons
The resource is unavailable due to legal reasons such as censorship or GDPR compliance.
500 Internal Server Error • Common
The server encountered an unexpected condition that prevented it from fulfilling the request.
501 Not Implemented
The server does not recognize or cannot implement the request method.
502 Bad Gateway • Common
The server, acting as a gateway, received an invalid response from an upstream server.
503 Service Unavailable • Common
The server is temporarily unable to handle the request — overloaded or under maintenance.
504 Gateway Timeout • Common
The server, acting as a gateway, did not receive a timely response from an upstream server.
505 HTTP Version Not Supported
The server does not support the HTTP version used in the request.
507 Insufficient Storage
The server cannot store the representation needed to complete the request (WebDAV).
508 Loop Detected
The server detected an infinite loop while processing a request (WebDAV).
510 Not Extended
The server requires further extensions for the request to be fulfilled.
511 Network Authentication Required
The client needs to authenticate to gain network access (captive portal).