100Continue
The initial part of the request has been received; the client should continue.
101Switching Protocols
The server is switching to a different protocol as requested by the client.
103Early Hints
Used with Link header to preload resources before final response.
200OK
Standard successful response.
201Created
The request succeeded and a new resource was created.
202Accepted
The request has been accepted for processing, but not completed.
204No Content
Request succeeded with no response body.
206Partial Content
Response contains a partial range of the resource (used for range requests).
301Moved Permanently
The resource has permanently moved to a new URL.
302Found
The resource is temporarily located at a different URL.
304Not Modified
Cached version is still valid; body is not sent.
307Temporary Redirect
Same method must be used for the redirected request.
308Permanent Redirect
Permanent redirect; method must not change.
400Bad Request
The server could not understand the request due to invalid syntax.
401Unauthorized
Authentication is required and has failed or not been provided.
403Forbidden
The server understood the request but refuses to authorize it.
404Not Found
The requested resource could not be found.
405Method Not Allowed
The HTTP method is not supported for this resource.
408Request Timeout
The server timed out waiting for the request.
409Conflict
The request conflicts with the current state of the resource.
410Gone
The resource has been permanently removed.
413Payload Too Large
Request entity exceeds server-defined limits.
415Unsupported Media Type
The media type of the request data is not supported.
418I'm a teapot
An April Fools' RFC joke — the server refuses to brew coffee.
422Unprocessable Entity
The request was well-formed but semantically invalid.
429Too Many Requests
The user has sent too many requests in a given amount of time.
451Unavailable For Legal Reasons
Content blocked for legal reasons.
500Internal Server Error
A generic server-side error occurred.
501Not Implemented
The server does not support the request method.
502Bad Gateway
The server received an invalid response from an upstream server.
503Service Unavailable
The server is temporarily unavailable, usually due to maintenance or overload.
504Gateway Timeout
An upstream server did not respond in time.
511Network Authentication Required
The client must authenticate to gain network access (captive portal).