404 or 410?
404 Not Found means nothing is at the URL; 410 Gone means it was removed on purpose and won't come back, which tells search engines to drop it sooner.
HTTP Status Codes
Look up what any HTTP status code means, from 100 Continue to 511, in plain English.
For example 404, 5xx or “too many”
47 codes
- 100
ContinueInformational
The server got the request headers; the client can send the body.
- 101
Switching ProtocolsInformational
The server is switching protocols, for example to WebSocket.
- 103
Early HintsInformational
Headers sent early so the browser can start preloading resources.
- 200
OKSuccess
The request succeeded.
- 201
CreatedSuccess
The request succeeded and a new resource was created.
- 202
AcceptedSuccess
The request was accepted for processing, which hasn't finished yet.
- 204
No ContentSuccess
The request succeeded and there is nothing to send back.
- 206
Partial ContentSuccess
Only part of the resource is sent, as asked for with a Range header.
- 301
Moved PermanentlyRedirection
The resource has a new permanent URL; search engines pass ranking to it.
- 302
FoundRedirection
The resource is temporarily at another URL.
- 303
See OtherRedirection
Fetch the result from another URL with GET, for example after a form is sent.
- 304
Not ModifiedRedirection
The cached copy is still up to date; nothing is sent again.
- 307
Temporary RedirectRedirection
Temporarily at another URL; the method and body must not change.
- 308
Permanent RedirectRedirection
Permanently at another URL; the method and body must not change.
- 400
Bad RequestClient error
The server can't process the request because it is malformed.
- 401
UnauthorizedClient error
Authentication is needed, or the credentials given are wrong.
- 402
Payment RequiredClient error
Reserved; some services use it when a payment or plan is needed.
- 403
ForbiddenClient error
The server understood the request but refuses it, even with login.
- 404
Not FoundClient error
Nothing exists at this URL.
- 405
Method Not AllowedClient error
This URL doesn't accept that method, such as POST.
- 406
Not AcceptableClient error
No version of the resource matches the Accept headers.
- 408
Request TimeoutClient error
The client took too long to send the request.
- 409
ConflictClient error
The request conflicts with the current state, such as an edit conflict.
- 410
GoneClient error
The resource was removed on purpose and won't come back.
- 411
Length RequiredClient error
The request needs a Content-Length header.
- 412
Precondition FailedClient error
A condition in the request headers (such as If-Match) is false.
- 413
Content Too LargeClient error
The request body is larger than the server accepts.
- 414
URI Too LongClient error
The URL is longer than the server accepts.
- 415
Unsupported Media TypeClient error
The server doesn't accept the body's format (Content-Type).
- 416
Range Not SatisfiableClient error
The requested byte range is outside the file.
- 418
I'm a teapotClient error
An April Fools' joke from RFC 2324; not a real error.
- 422
Unprocessable ContentClient error
The request is well-formed but has invalid data, such as a form error.
- 425
Too EarlyClient error
The server won't risk processing a request that might be replayed.
- 426
Upgrade RequiredClient error
The client must switch to another protocol, such as TLS.
- 428
Precondition RequiredClient error
The request must be conditional, to prevent lost updates.
- 429
Too Many RequestsClient error
Rate limit reached; wait before trying again (see Retry-After).
- 431
Request Header Fields Too LargeClient error
The headers, often cookies, are too large.
- 451
Unavailable For Legal ReasonsClient error
Blocked for legal reasons, such as a court order.
- 500
Internal Server ErrorServer error
Something went wrong on the server; the request may be fine.
- 501
Not ImplementedServer error
The server doesn't support the feature needed.
- 502
Bad GatewayServer error
A proxy or CDN got an invalid response from the server behind it.
- 503
Service UnavailableServer error
The server is overloaded or down for maintenance; try again later.
- 504
Gateway TimeoutServer error
A proxy or CDN gave up waiting for the server behind it.
- 505
HTTP Version Not SupportedServer error
The server doesn't support the HTTP version used.
- 507
Insufficient StorageServer error
The server can't store what is needed to finish the request.
- 508
Loop DetectedServer error
The server found an infinite loop while processing the request.
- 511
Network Authentication RequiredServer error
Log in to the network first, as on hotel Wi-Fi.
Runs in your browser — nothing you enter is sent to a server.
How the HTTP Status Codes works
Type a status code, the first digits of one, a class such as 4xx, or words like "too many". Each code is listed with its official name from the IANA registry and a plain-English explanation.
The first digit gives the class:
- 1xx informational — the request is still in progress
- 2xx success
- 3xx redirection — look somewhere else
- 4xx client error — the request itself is wrong
- 5xx server error — the request may be fine; the server failed
Examples
301 or 308?
Both are permanent redirects. 308 also requires the method and body to stay the same, so a POST stays a POST.
Frequently asked questions
What does 429 mean?
Too Many Requests: a rate limit was reached. Wait before trying again; the Retry-After header often says how long.
What is the difference between 401 and 403?
401 means you aren't logged in (or the credentials are wrong). 403 means you are known but not allowed.
Is 418 a real error?
It's an April Fools' joke from 1998 (RFC 2324, "I'm a teapot") that stayed reserved because so many servers use it for fun.
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