HTTP ステータスコード一覧

The initial part of the request has been received and the client should continue sending the rest.

The server is switching protocols as requested in the Upgrade header (e.g., to WebSocket).

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

Used to preload resources while the server prepares the final response.

The request succeeded. The meaning depends on the HTTP method used.

The request succeeded and a new resource was created — typically returned after POST.

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

The request succeeded but no body is returned — common for PUT or DELETE.

Tells the client to reset the view that sent the request (e.g., clear a form).

Returned when the client used the Range header to request a portion of the resource.

WebDAV — multiple resources, each with its own status code, returned inside an XML body.

The resource has a new permanent URL. Search engines update their index to the new location.

The resource is temporarily at a different URL — client should keep using the original URL for future requests.

After a POST, redirect the client to GET another resource (PRG pattern).

The cached version is still fresh — the client should use its cache.

Like 302, but the request method must not change on the redirect.

Like 301, but the request method must not change on the redirect.

The server cannot process the request due to a client-side error (malformed syntax, missing required fields).

Authentication is required and either missing or invalid. The response should include a WWW-Authenticate header.

Reserved for future use — sometimes used by APIs to indicate billing-related failures.

The server understood the request but refuses to authorize it. Authentication will not help.

The requested resource does not exist on the server.

The HTTP method is not supported for this resource (e.g., POST to a read-only endpoint).

The server cannot return a response matching the Accept headers from the request.

Authentication with a proxy is required to access the resource.

The server did not receive a complete request within its idle timeout.

The request conflicts with the current state of the resource (e.g., concurrent edits).

The resource is permanently gone — stronger than 404; tells caches and search engines to drop it.

The request did not specify a Content-Length, which this server requires.

A condition in the request headers (e.g., If-Match) was not met.

The request body is larger than the server is willing to process.

The URI is longer than the server is willing to interpret.

The Content-Type of the request is not supported by the server.

The Range header cannot be fulfilled (out of the resource bounds).

The Expect header could not be fulfilled by the server.

An April Fools joke from RFC 2324 — used as an Easter egg in some APIs.

The request is syntactically correct but semantically wrong (failed validation). Common in REST APIs.

WebDAV — the resource is locked.

WebDAV — the request failed because a previous request it depended on failed.

The server is unwilling to risk processing a request that may be replayed.

The client should upgrade to a different protocol (e.g., TLS).

The server requires the request to be conditional (e.g., If-Match).

The client has sent too many requests in a given time — rate limited. Look for Retry-After.

The request headers are too large in total or individually.

The resource is blocked due to a legal demand (named after Ray Bradbury's Fahrenheit 451).

A generic server error — something failed and the server has no more specific message.

The server does not support the functionality required to fulfill the request.

Acting as a gateway / proxy, the server got an invalid response from an upstream server.

The server is temporarily unable to handle requests — overloaded or down for maintenance.

Acting as a gateway / proxy, the server did not get a response from an upstream server in time.

The HTTP version in the request is not supported by the server.

WebDAV — the server cannot store the representation needed to complete the request.

WebDAV — the server detected an infinite loop while processing the request.

The client must authenticate to gain network access (used by captive portals).