HTTP Status Code Lookup

The server received the request headers; the client should send the request body.

The server is switching to the protocol the client requested (e.g. WebSocket upgrade).

The server accepted the request but has not completed it yet (WebDAV).

Preliminary headers (like preload links) sent before the final response.

The request succeeded. The standard response for successful requests.

The request succeeded and a new resource was created — typical for POST.

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

The response was modified by a proxy from the origin server's response.

The request succeeded but there is no body to return — common for DELETE.

The client should reset the document view (e.g. clear a form).

Only part of the resource is returned, due to a Range header — used for resumable downloads and video streaming.

Multiple status values for multiple operations (WebDAV).

The response is a result of instance manipulations applied to the resource.

More than one representation of the resource exists; the client should pick one.

The resource has a new permanent URL. Browsers and search engines update their links — important for SEO redirects.

The resource is temporarily at a different URL. The original URL should keep being used.

The response is at another URL and should be fetched with GET — common after form submissions.

The cached version is still valid; no body is sent. Saves bandwidth with ETag / If-Modified-Since.

Like 302, but the request method must not change (POST stays POST).

Like 301, but the request method must not change (POST stays POST).

The server can't process the request — malformed syntax, invalid parameters, or bad JSON.

Authentication is required or the provided credentials are invalid. Send a valid Authorization header.

Reserved for future use; some APIs use it for quota or billing issues.

The server understood the request but refuses it — you're authenticated but not allowed.

The requested resource doesn't exist at this URL. The most famous status code.

The HTTP method (GET, POST, …) isn't supported by this endpoint.

No response matches the client's Accept headers.

The client must authenticate with the proxy first.

The client took too long to send the request; the server closed the connection.

The request conflicts with the current state — e.g. an edit collision or duplicate entry.

The resource existed but was permanently removed. Stronger than 404 for SEO cleanup.

The request must include a Content-Length header.

A conditional header (If-Match, If-Unmodified-Since) failed — used for optimistic locking.

The request body exceeds what the server accepts — common on file uploads.

The URL is longer than the server will process.

The request body format isn't supported — e.g. sending XML to a JSON-only API.

The Range header asks for a part of the file that doesn't exist.

The Expect request header could not be met.

April Fools' joke from RFC 2324 — the server refuses to brew coffee because it is a teapot.

The request is well-formed but semantically invalid — the classic validation-error response in REST APIs.

The server won't risk processing a request that might be replayed.

The client should switch to a different protocol (see the Upgrade header).

The server requires conditional headers to prevent lost updates.

Rate limit exceeded. Check the Retry-After header before retrying.

Headers (often cookies) are too big for the server to process.

Content blocked for legal reasons — named after Fahrenheit 451.

A generic, unexpected server-side failure — check the server logs.

The server doesn't support the functionality needed to fulfill the request.

A gateway or reverse proxy got an invalid response from the upstream server.

The server is overloaded or down for maintenance — usually temporary, may include Retry-After.

A gateway or proxy didn't get a response from the upstream server in time.

The HTTP protocol version in the request isn't supported.

The server can't store what's needed to complete the request (WebDAV).

The server detected an infinite loop while processing (WebDAV).

The client must authenticate to the network first — e.g. a Wi-Fi captive portal.