Reference

HTTP Status Codes

Complete reference for all 62 HTTP response status codes. Each code explained with common causes, fixes, and context for web developers and SEO professionals.

4xx

Client Error

The request contains an error or cannot be fulfilled. The client should modify the request before retrying.

400 Bad Request

The server cannot process the request due to a client-side error in the request.

401 Unauthorized

The request requires authentication and valid credentials were not provided.

402 Payment Required

This code is reserved for future use in digital payment systems.

403 Forbidden

The server understood the request but refuses to authorize it.

404 Not Found

The server cannot find the requested resource at this URL.

405 Method Not Allowed

The HTTP method used is not supported for this URL.

406 Not Acceptable

The server cannot produce a response matching the client's Accept headers.

407 Proxy Authentication Required

The client must first authenticate with the proxy server.

408 Request Timeout

The server timed out waiting for the client to finish sending the request.

409 Conflict

The request conflicts with the current state of the resource on the server.

410 Gone

The resource has been permanently removed and will not be available again.

411 Length Required

The server requires a Content-Length header that was not included in the request.

412 Precondition Failed

One or more conditions in the request headers evaluated to false on the server.

413 Content Too Large

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

414 URI Too Long

The requested URL is longer than the server is willing to interpret.

415 Unsupported Media Type

The server does not support the media type of the request body.

416 Range Not Satisfiable

The requested byte range is outside the bounds of the resource.

417 Expectation Failed

The server cannot meet the requirements specified in the Expect request header.

418 I'm a Teapot

The server refuses to brew coffee because it is, permanently, a teapot.

421 Misdirected Request

The request was sent to a server that cannot produce a response for it.

422 Unprocessable Content

The request body is syntactically correct but contains semantic errors.

423 Locked

The resource is currently locked and cannot be modified.

424 Failed Dependency

The request failed because it depended on another request that also failed.

425 Too Early

The server is unwilling to process a request that might be replayed.

426 Upgrade Required

The server requires the client to switch to a different protocol to proceed.

428 Precondition Required

The server requires the request to include conditional headers.

429 Too Many Requests

The client has sent too many requests in a given amount of time.

431 Request Header Fields Too Large

The server refuses the request because the headers are too large.

451 Unavailable For Legal Reasons

The resource is unavailable due to legal restrictions or censorship demands.

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