HTTP Status Codes Reference
Look up any HTTP status code — 200, 301, 404, 500, and the rest — with its meaning and when it's used. Searchable, grouped by class, fully client-side.
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39 of 39 codes
1xx Informational
100
Continue
The client should continue with its request; the initial part was received.
101
Switching Protocols
The server is switching protocols as requested by the client (e.g. to WebSocket).
102
Processing
The server has received and is processing the request, but no response is available yet (WebDAV).
103
Early Hints
Used to return some response headers before the final response, so the client can preload resources.
2xx Success
200
OK
The request succeeded. The meaning depends on the method (GET returns the resource, POST the result).
201
Created
The request succeeded and a new resource was created, usually after a POST or PUT.
202
Accepted
The request was accepted for processing, but the processing is not complete.
204
No Content
The request succeeded but there is no content to send in the response body.
206
Partial Content
The server is delivering only part of the resource due to a Range header (used for resumable downloads and streaming).
3xx Redirection
301
Moved Permanently
The resource has permanently moved to a new URL. Search engines update their links; the new URL is in Location.
302
Found
The resource is temporarily at a different URL. Keep using the original URL for future requests.
303
See Other
The response can be found under another URL using GET — often used after a POST to redirect to a result page.
304
Not Modified
The cached version is still valid, so the server sends no body. Saves bandwidth via conditional requests.
307
Temporary Redirect
Like 302, but the method and body must not change on the redirected request.
308
Permanent Redirect
Like 301, but the method and body must not change on the redirected request.
4xx Client Error
400
Bad Request
The server can't process the request due to a client error, such as malformed syntax.
401
Unauthorized
Authentication is required and has failed or not been provided. (Really means 'unauthenticated'.)
402
Payment Required
Reserved for future use; occasionally used by APIs to signal a billing or quota issue.
403
Forbidden
The server understood the request but refuses to authorize it. Authenticating won't help.
404
Not Found
The server can't find the requested resource. The URL may be wrong or the resource removed.
405
Method Not Allowed
The HTTP method is not supported for this resource (e.g. POST to a read-only endpoint).
406
Not Acceptable
The resource can't be returned in a format the client accepts (per the Accept headers).
408
Request Timeout
The server timed out waiting for the request. The client may repeat it.
409
Conflict
The request conflicts with the current state of the resource, such as an edit collision.
410
Gone
The resource is permanently gone with no forwarding address — a deliberate, stronger 404.
413
Payload Too Large
The request body is larger than the server is willing or able to process.
415
Unsupported Media Type
The request's media type (Content-Type) is not supported by the server.
418
I'm a teapot
An April Fools' joke code from 1998 — the server refuses to brew coffee because it is a teapot.
422
Unprocessable Entity
The request was well-formed but has semantic errors (common for validation failures in APIs).
429
Too Many Requests
The client has sent too many requests in a given time — rate limited. Check the Retry-After header.
431
Request Header Fields Too Large
The server refuses the request because the header fields are too large.
451
Unavailable For Legal Reasons
The resource is unavailable due to legal demands, such as censorship or a takedown.
5xx Server Error
500
Internal Server Error
A generic server-side error — something went wrong and the server has no more specific message.
501
Not Implemented
The server does not support the functionality required to fulfil the request.
502
Bad Gateway
A server acting as a gateway or proxy received an invalid response from the upstream server.
503
Service Unavailable
The server is temporarily unable to handle the request — overloaded or down for maintenance.
504
Gateway Timeout
A gateway or proxy did not get a timely response from the upstream server.
505
HTTP Version Not Supported
The server does not support the HTTP protocol version used in the request.
511
Network Authentication Required
The client must authenticate to gain network access — often seen on captive-portal Wi-Fi.
HTTP status codes are grouped by their first digit: 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors. This reference runs entirely in your browser.
A quick, searchable reference for HTTP status codes — what each one means and when it's used. Search by number or keyword and browse the results grouped by class, from 1xx through 5xx. Runs entirely in your browser.
Private by design — your data never leaves your device
How to use it
No account, no upload — it all happens on your device.
1
Type a code (like 404) or a keyword (like 'redirect') in the search box.
2
Browse the matching codes, grouped by class.
3
Read each code's name and what it means.
The five classes
The first digit tells the story.
- 1xx Informational — the request was received; the process continues.
- 2xx Success — the request was received, understood, and accepted.
- 3xx Redirection — further action is needed to complete the request (usually following a new URL).
- 4xx Client Error — the request was malformed or not allowed; the client should change something.
- 5xx Server Error — the server failed to fulfil a valid request.
The ones you'll meet most
200 (OK), 301/302 (redirects), 304 (cached, not modified), 400 (bad request), 401/403 (auth), 404 (not found), 429 (rate limited), and 500/502/503 (server problems) cover the vast majority of day-to-day web development.
Frequently asked
What do the code classes mean?
The first digit sets the category: 1xx informational, 2xx success, 3xx redirection, 4xx client errors (the request was wrong), and 5xx server errors (the server failed). Knowing the class tells you roughly whose fault a response is.
What's the difference between 301 and 302?
301 Moved Permanently tells browsers and search engines the resource has a new home for good, so they update their links. 302 Found is temporary — keep using the original URL. Use 301 for permanent moves and 302 (or 307) for temporary ones.
Is 401 or 403 right for a blocked request?
Use 401 Unauthorized when the user isn't authenticated (no or bad credentials) — logging in could fix it. Use 403 Forbidden when they're authenticated but not allowed; logging in again won't help.