HTTP Status Codes — Enterno.io
HTTP Status Codes
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1xx — Informational
100
Continue
Server received request headers, client can continue sending body.
101
Switching Protocols
Server is switching protocols as requested by client (e.g., WebSocket).
102
Processing
(WebDAV) Request accepted, processing continues.
103
Early Hints
Early hints — browser can start preloading resources before final response.
2xx — Success
200
OK
Request succeeded. Standard response for GET/POST.
201
Created
Resource created successfully. Usually after POST. Location header points to new resource.
202
Accepted
Request accepted but processing not yet complete (async operations).
203
Non-Authoritative Information
Response received from intermediate proxy, not from origin server.
204
No Content
Success, response body is empty. Often used for DELETE and PUT.
205
Reset Content
Success. Browser should reset the form/document.
206
Partial Content
Partial response to a Range request (resume download, streaming).
207
Multi-Status
(WebDAV) Response contains multiple statuses for different resources.
208
Already Reported
(WebDAV) Elements already listed in a previous part of the response.
226
IM Used
Server returned delta encoding (HTTP Delta Encoding).
3xx — Redirection
300
Multiple Choices
Multiple resource variants available — client must choose.
301
Moved Permanently
Permanent redirect. Search engines transfer link equity to new URL.
302
Found
Temporary redirect. Request method may change to GET.
303
See Other
Redirect to another resource via GET (after POST/PUT/DELETE).
304
Not Modified
Resource not modified — browser should use cached version.
307
Temporary Redirect
Temporary redirect preserving request method and body.
308
Permanent Redirect
Permanent redirect preserving request method and body.
4xx — Client Error
400
Bad Request
Malformed request syntax or invalid parameters.
401
Unauthorized
Authentication required. WWW-Authenticate header specifies scheme.
402
Payment Required
Reserved for payment systems (rarely used).
403
Forbidden
Server understood the request but refuses access.
404
Not Found
Resource not found on server.
405
Method Not Allowed
HTTP method not supported for this URL. Allow header lists permitted methods.
406
Not Acceptable
Server cannot return response in format specified by client Accept header.
407
Proxy Auth Required
Authentication required on proxy server.
408
Request Timeout
Client took too long to send request — connection closed.
409
Conflict
Resource state conflict (e.g., version mismatch in optimistic locking).
410
Gone
Resource permanently deleted. Unlike 404, this is final.
411
Length Required
Content-Length header is required.
412
Precondition Failed
Condition in If-Match / If-None-Match not met.
413
Content Too Large
Request body exceeds allowed size.
414
URI Too Long
Request URL is too long.
415
Unsupported Media Type
Request body format (Content-Type) not supported.
416
Range Not Satisfiable
Requested byte range is not available.
417
Expectation Failed
Server cannot meet condition from Expect header.
418
I'm a teapot
April Fools' RFC 2324. Teapot refuses to brew coffee.
421
Misdirected Request
Request sent to a server that cannot produce an authoritative response.
422
Unprocessable Entity
Syntax is correct but semantic error in data.
423
Locked
(WebDAV) Resource is locked.
424
Failed Dependency
(WebDAV) Failed due to failure of a previous request.
425
Too Early
Server unwilling to process a request that might be replayed.
426
Upgrade Required
Client must switch to a different protocol (e.g., TLS).
428
Precondition Required
Conditional request required to prevent conflicts.
429
Too Many Requests
Rate limit exceeded. Retry-After header specifies wait time.
431
Headers Too Large
Request headers are too large.
451
Unavailable For Legal Reasons
Resource unavailable for legal reasons (censorship, copyright).
5xx — Server Error
500
Internal Server Error
Unhandled server error. Check logs.
501
Not Implemented
Server does not support the functionality required to fulfill the request.
502
Bad Gateway
Proxy/load balancer received invalid response from upstream server.
503
Service Unavailable
Service temporarily unavailable: overload or scheduled maintenance.
504
Gateway Timeout
Upstream server did not respond in time.
505
HTTP Version Not Supported
HTTP version in request is not supported.
506
Variant Also Negotiates
Transparent content negotiation configuration error.
507
Insufficient Storage
(WebDAV) Not enough storage to complete the request.
508
Loop Detected
(WebDAV) Infinite loop detected while processing request.
510
Not Extended
Request extension required for processing.
511
Network Auth Required
Network authentication required (e.g., captive portal Wi-Fi).
520
Web Server Returns Unknown
(Cloudflare) Unknown response from origin server behind Cloudflare.
521
Web Server Is Down
(Cloudflare) Origin server refused connection from Cloudflare.
522
Connection Timed Out
(Cloudflare) Connection to origin server timed out.
523
Origin Is Unreachable
(Cloudflare) Origin server is unreachable.
524
A Timeout Occurred
(Cloudflare) Connection established but server did not respond in time.
525
SSL Handshake Failed
(Cloudflare) SSL handshake with origin server failed.
526
Invalid SSL Certificate
(Cloudflare) Invalid SSL certificate on origin server.
Frequently Asked Questions
What are HTTP headers?
HTTP headers are metadata sent along with HTTP requests or responses. They contain information about content type, caching, security and other parameters.
What does status code 200 mean?
HTTP 200 OK — the request was successful. The server returned the requested resource.
What does status code 301 mean?
HTTP 301 Moved Permanently — permanent redirect. The resource has moved to a new URL.
What does status code 404 mean?
HTTP 404 Not Found — the requested resource was not found on the server.
What does status code 500 mean?
HTTP 500 Internal Server Error — internal server error. The server could not fulfill the request.