Through HTTP status codes, machines point out if HTTP requests were completed or not and why. Understanding the status codes’ meaning can save you time and effort while trying to fix a failure.

Complete list of HTTP status codes.

An HTTP status code is a numeric representation used by servers to convey the result of a client’s HTTP request, providing information about the success, error, or additional action needed for the request.

There are five categories of HTTP status codes: Server error, client error, redirection, successful, and informational.

5xx server error

500 Internal server error. The server found a condition that prevented it from fulfilling the request.

501 Not implemented. The server can’t handle the request because it doesn’t support the required functionality.

502 Bad gateway.

503 Service unavailable.

504 Gateway timeout.

505 HTTP version not supported.

506 Variant also negotiates. Internal setting up error on the server.

507 Insufficient storage.

508 Loop detected.

509 Bandwidth limit exceeded (Apache).

510 Not extended.

511 Network authentication required.

598 Network read timeout error required.

4xx Client error

400 Bad request. The server didn’t understand the request because of the invalid syntax on it.

401 Unauthorized. The request demands the authentication of the user.

402 Payment required.

403 Forbidden. The request is legal, but the server refused to fulfill it. Authentication here won’t make a difference.

404 Not found.

405 Method not allowed.

406 Not acceptable.

407 Proxy authentication required.

408 Request timeout.

409 Conflict. 

410 Gone. The resource requested is not available at the server anymore, and there’s no known forward address.

411 Length required.

412 Precondition failed.

413 Payload too large.

414 URI too long.

415 Unsupported media type.

416 Range not satisfiable.

417 Expectation failed.

418 I’m a teapot.

421 Misdirected request.

422 Unprocessable entity.

423 Locked.

424 Failed dependency.

425 Too early.

426 Upgrade required.

428 Precondition required.

429 Too many requests.

431 Request header fields too large.

450 Blocked by Windows Parental Controls (Microsoft).

451 Unavailable for legal reasons.

3xx redirection.

300 Multiple choices.

301 Moved permanently. The resource requested was changed permanently to a different URL.

302 Found. The resource requested was changed to another URL temporarily.

303 See other. The request’s response can be found on a different URL that should be recovered through a GET method.

304 Not modified.

305 Use proxy.

306 Switch proxy.

307 Temporary redirect.

308 Permanent Redirect (experimental).

Web redirect record: How to use it?

2xx successful

200 Ok. It states the success of the request.

201 Created. The request was fulfilled, so a new resource was created.

202 Accepted. The request was accepted to be processed, but its process is not completed yet. 

203 Non-authoritative information.

204 No content.

205 Reset content.

206 Partial content.

207 Multi-status.

208 Already reported.

226 IM used.

1xx informational

100 Continue. The server received the first part of the request. 

101 Switching protocols.

102 Processing. The server accepted the full request, but it’s not fully completed yet.

103 Early hints. It allows the user agent the pre-loading of resources while the server gets a response ready.

Suggested article: Most frequently used DNS commands.

Conclusion.

Next time you get an HTTP status code, pay attention to it! It’s the clue you need to fix the cause of an issue without delay.