What's the difference between 401 and 403?
401 Unauthorized means you're not authenticated (missing/invalid credentials); 403 Forbidden means you are authenticated but lack permission.
HTTP Status Code Lookup
Search status codes
Showing 48 of 83 matching entries — narrow the search to see the rest.
Status details
200
OK
2xx Success
- Description
- The request completed successfully.
- Common usage
- Returned for successful page, API, and resource requests.
- Related
204 is the same success with no body at all, used when there is nothing to send back.
202 means the work was only accepted, not finished — a 200 says the result is in this response.
2xx Success83 codes
All 83 HTTP status codes
Every code in the lookup above, grouped by class and by source. Standard codes come from the IANA registry; the nginx, Cloudflare, and unofficial sections cover codes you meet in logs and error pages that are not part of any RFC.
1xx Informational (4)
- 100 Continue
- The initial part of the request was received and may continue.
- 101 Switching Protocols
- The server is switching to a different protocol as the client requested.
- 102 Processing
- The server accepted the request but has not finished it yet.
- 103 Early Hints
- Preliminary headers sent before the final response, so the client can start preloading.
2xx Success (10)
- 200 OK
- The request completed successfully.
- 201 Created
- The request succeeded and created a new resource.
- 202 Accepted
- The request was accepted for processing, which has not completed.
- 203 Non-Authoritative Information
- The request succeeded, but a proxy modified the origin server's response.
- 204 No Content
- The request succeeded and there is no response body.
- 205 Reset Content
- The request succeeded and the client should reset the document that sent it.
- 206 Partial Content
- The server is returning only the part of the resource the client asked for.
- 207 Multi-Status
- The body holds separate status codes for several independent operations.
- 208 Already Reported
- The members of this binding were already listed earlier in the same response.
- 226 IM Used
- The response is the result of applying instance manipulations to the resource.
3xx Redirection (9)
- 300 Multiple Choices
- The request has more than one possible response and the client must pick one.
- 301 Moved Permanently
- The requested resource has permanently moved to another URL.
- 302 Found
- The requested resource is temporarily available at another URL.
- 303 See Other
- The result is at another URL that the client should fetch with GET.
- 304 Not Modified
- The cached resource is still current and does not need to be transferred again.
- 305 Use Proxy
- The resource must be reached through the proxy named in the response.
- 306 (Unused)
- Reserved from an earlier HTTP draft and no longer used by anything.
- 307 Temporary Redirect
- Temporarily at another URL, and the client must not change the request method.
- 308 Permanent Redirect
- The requested resource has permanently moved, and the request method must not change.
4xx Client Error (28)
- 400 Bad Request
- The server cannot process the request because it is malformed or invalid.
- 401 Unauthorized
- Authentication is required or the supplied credentials are invalid.
- 402 Payment Required
- Reserved for payment-related conditions and not standardized in practice.
- 403 Forbidden
- The server understood the request but refuses to fulfill it.
- 404 Not Found
- The server cannot find the requested resource.
- 405 Method Not Allowed
- The origin server knows the request method, but the target resource does not support it.
- 406 Not Acceptable
- The server cannot produce a response matching the request's Accept headers.
- 407 Proxy Authentication Required
- The client must authenticate with the proxy before the request can be forwarded.
- 408 Request Timeout
- The server gave up waiting for the client to finish sending the request.
- 409 Conflict
- The request conflicts with the current state of the resource.
- 410 Gone
- The resource was deliberately removed and will not come back.
- 411 Length Required
- The server refuses the request because it has no Content-Length header.
- 412 Precondition Failed
- A condition in the request headers did not hold on the server.
- 413 Content Too Large
- The request body is larger than the server is willing to process.
- 414 URI Too Long
- The request URL is longer than the server is willing to interpret.
- 415 Unsupported Media Type
- The body's format is not one the endpoint can accept.
- 416 Range Not Satisfiable
- The requested byte range lies outside the size of the resource.
- 417 Expectation Failed
- The server cannot meet the requirement given in the Expect header.
- 421 Misdirected Request
- The request reached a server that cannot produce a response for that authority.
- 422 Unprocessable Content
- The syntax and content type are valid, but the instructions inside could not be processed.
- 423 Locked
- The resource is locked and cannot be changed by this request.
- 424 Failed Dependency
- The request failed because an action it depended on failed first.
- 425 Too Early
- The server will not risk processing a request that might be replayed.
- 426 Upgrade Required
- The client must switch to a different protocol to use this resource.
- 428 Precondition Required
- The server requires the request to be conditional.
- 429 Too Many Requests
- The client sent too many requests within a given period.
- 431 Request Header Fields Too Large
- The request headers are too large for the server to process.
- 451 Unavailable For Legal Reasons
- The resource is blocked for legal reasons such as a court order or censorship.
5xx Server Error (11)
- 500 Internal Server Error
- The server encountered an unexpected condition and could not complete the request.
- 501 Not Implemented
- The server does not support the functionality the request requires.
- 502 Bad Gateway
- A gateway or proxy received an invalid response from an upstream server.
- 503 Service Unavailable
- The server is temporarily unable to handle the request.
- 504 Gateway Timeout
- A gateway or proxy did not receive a timely upstream response.
- 505 HTTP Version Not Supported
- The server refuses the major HTTP version used in the request.
- 506 Variant Also Negotiates
- Content negotiation is misconfigured and refers back to itself in a loop.
- 507 Insufficient Storage
- The server has no room to store what the request needs to complete.
- 508 Loop Detected
- The server stopped the request because it detected an infinite loop.
- 510 Not Extended
- The request needs further extensions before the server will fulfil it.
- 511 Network Authentication Required
- The client must authenticate with the network before it can reach the internet.
Unofficial (6)
- 418 I'm a Teapot
- An April Fools joke code from 1998, kept reserved so it is never reassigned.
- 419 Page Expired
- Laravel returns this when a form CSRF token is missing or has expired.
- 420 Enhance Your Calm
- A rate-limit code from the retired Twitter API v1, replaced by the standard 429.
- 430 Request Header Fields Too Large
- Shopify uses this when too many URLs were requested at once.
- 450 Blocked by Windows Parental Controls
- Windows Parental Controls blocked access to the requested page.
- 498 Invalid Token
- ArcGIS returns this when an auth token is expired or otherwise invalid.
nginx (6)
- 444 No Response
- nginx closes the connection with no response at all.
- 494 Request Header Too Large
- nginx logs this when request headers exceed its buffer size.
- 495 SSL Certificate Error
- nginx rejected the client TLS certificate as invalid.
- 496 SSL Certificate Required
- nginx required a client TLS certificate and the client sent none.
- 497 HTTP Request Sent to HTTPS Port
- A plain HTTP request arrived on a port nginx serves over HTTPS.
- 499 Client Closed Request
- The client disconnected before nginx could send a response.
Cloudflare (9)
- 520 Web Server Returned an Unknown Error
- The origin returned something Cloudflare could not interpret as a valid response.
- 521 Web Server Is Down
- The origin refused Cloudflare's connection.
- 522 Connection Timed Out
- Cloudflare could not establish a TCP connection to the origin in time.
- 523 Origin Is Unreachable
- Cloudflare could not route to the origin at all.
- 524 A Timeout Occurred
- The origin accepted the connection but did not finish replying in time.
- 525 SSL Handshake Failed
- The TLS handshake between Cloudflare and the origin failed.
- 526 Invalid SSL Certificate
- Cloudflare could not validate the certificate the origin presented.
- 527 Railgun Error
- A Cloudflare Railgun connection failed, from a product that has been retired.
- 530 Origin DNS Error
- Cloudflare could not resolve the origin hostname, and shows a 1xxx error with it.
About this HTTP Status Code Lookup
Find common HTTP response codes, meanings, and usage details.
Covers every code in the IANA registry plus the vendor codes you meet in real logs: nginx (444, 499), Cloudflare (520–527, 530), and unofficial ones such as 419 and 420. Search matches the code, the name, the class, the vendor, or the description — typing 5xx lists every server error, cloudflare lists the edge codes, and rate limit finds 429. Every code has its own shareable link (?code=404), the full list is below, and the FAQ untangles the pairs that get mixed up most — 301 vs 302, 401 vs 403, 502 vs 504.
FAQ
What's the difference between 301 and 302?
301 Moved Permanently means the URL has changed for good, so clients and search engines should switch to the new one. 302 Found is temporary — the client should keep using the original URL next time.
What's the difference between 200 and 204?
200 OK returns a response body along with the success. 204 No Content confirms success with no body at all — common for a successful DELETE or an update with nothing new to send back.
What's the difference between 500 and 503?
500 Internal Server Error means the server hit an unexpected bug or unhandled exception. 503 Service Unavailable is a deliberate, usually temporary state — overload, maintenance, or a dependency outage — often paired with a Retry-After header.
What does 429 mean?
Too Many Requests — the client has exceeded a rate limit set by the server.
Does this check a live URL's actual status code?
No — this is a static reference lookup against a curated list of status codes and their meanings, not a live checker. To see what code a real URL returns, use your browser's DevTools Network tab or run curl -I <url>.
Is 200 always a success?
Yes by spec, but some APIs misuse 200 with an error code buried in the response body — this breaks HTTP semantics and confuses monitoring tools.
Is my lookup sent anywhere?
No — entirely client-side reference lookup.
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