Dev Reference Explorer

Request headers received; client should proceed to send the body.

Server is switching protocols as requested (e.g., WebSocket upgrade).

Sends preliminary Link headers so the browser can preload assets early.

Standard response for successful HTTP requests.

Request succeeded and a new resource was created (often with Location header).

Accepted for asynchronous processing, but not yet completed.

Succeeded with no response payload body (common for DELETE or PUT).

Partial byte range delivered in response to a Range header.

Batch response conveying status for multiple independent operations.

Permanent redirect; user agents may change POST to GET.

Temporary redirect to another URI specified in Location.

Redirects to another URI using GET after a POST (Post/Redirect/Get).

Resource has not changed since ETag / If-Modified-Since; use cached copy.

Temporary redirect that strictly preserves the HTTP method and body.

Permanent redirect that strictly preserves the HTTP method and body.

Malformed syntax, invalid JSON, or missing required parameters.

Unauthenticated: valid credentials or token required.

Authenticated, but lacks permission to access the target resource.

Resource not found at the requested URI.

Target resource does not support this HTTP method (see Allow header).

Server timed out waiting for the client to finish sending the request.

Conflict with current resource state (e.g., duplicate key or version mismatch).

Resource was permanently removed and is no longer available.

Precondition in If-Match / If-Unmodified-Since evaluated to false.

Request payload is larger than the server is willing or able to process.

Payload format (Content-Type) is not supported by the target resource.

HTCPCP easter egg: the server refuses to brew coffee because it is a teapot.

Well-formed syntax, but failed semantic or domain validation rules.

Rate limit exceeded; check the Retry-After header before retrying.

Access denied due to legal demand, censorship, or regional compliance.

Unhandled exception or unexpected condition on the server.

Server does not support the functionality required to fulfill the request.

Gateway or reverse proxy received an invalid response from upstream.

Server is temporarily overloaded or down for maintenance.

Gateway or reverse proxy timed out waiting for the upstream server.