What are HTTP status codes?

HTTP status codes are three-digit numbers a server returns to tell the client the result of a request. They are grouped into five classes: 1xx informational, 2xx success, 3xx redirection, 4xx client errors, and 5xx server errors. For example, 200 means OK and 404 means Not Found.

What does HTTP 404 mean?

404 Not Found means the server reached but could not find a resource matching the request URL. It is a client error (4xx) and usually indicates a broken link or a removed page, not a server failure.

What is the difference between 301 and 302?

301 Moved Permanently tells clients and search engines the resource has a new permanent URL, so they should update links and pass on ranking. 302 Found is a temporary redirect, so the original URL is kept. Use 301 for permanent moves and 302 (or 307) for temporary ones.

What does HTTP 500 mean?

500 Internal Server Error is a generic server-side failure (5xx): the server hit an unexpected condition and could not complete the request. Unlike 4xx codes, it is not caused by the client, and the fix is on the server.

429 Too Many Requests means the client has sent too many requests in a given time and is being rate-limited. The response often includes a Retry-After header telling the client when to try again.

HTTP Status Codes - Full List & Reference

HTTP Status Codes — Complete Reference

HTTP status codes are three-digit numbers a server returns with every response to describe the outcome of a request. They are organized into five classes by their first digit. The authoritative list is maintained by IANA and defined in RFC 9110. Below is every commonly used code with its meaning.

1xx Informational 2xx Success 3xx Redirection 4xx Client Error 5xx Server Error

1xx Informational

The request was received and the process is continuing.

Code	Name	Meaning
100	Continue	The client should continue with its request body.
101	Switching Protocols	The server is switching protocols as requested (e.g. to WebSocket).
102	Processing	The server has accepted the request but not yet completed it (WebDAV).
103	Early Hints	Preliminary headers (e.g. preload links) before the final response.

2xx Success

The request was successfully received, understood and accepted.

Code	Name	Meaning
200	OK	Standard success response. The body contains the result.
201	Created	The request succeeded and a new resource was created.
202	Accepted	The request was accepted for processing but is not complete.
204	No Content	Success, but there is no body to return.
206	Partial Content	The server is delivering part of the resource (range requests).

3xx Redirection

Further action is needed to complete the request.

Code	Name	Meaning
301	Moved Permanently	The resource has a new permanent URL; update links and pass ranking.
302	Found	Temporary redirect; keep using the original URL.
303	See Other	Get the resource from another URL with a GET request.
304	Not Modified	The cached copy is still valid; no body is sent.
307	Temporary Redirect	Like 302 but the method must not change.
308	Permanent Redirect	Like 301 but the method must not change.

4xx Client Error

The request contains bad syntax or cannot be fulfilled.

Code	Name	Meaning
400	Bad Request	The server could not understand the request (malformed syntax).
401	Unauthorized	Authentication is required or has failed.
403	Forbidden	The server understood but refuses to authorize the request.
404	Not Found	The resource could not be found at this URL.
405	Method Not Allowed	The HTTP method is not supported for this resource.
409	Conflict	The request conflicts with the current state of the resource.
410	Gone	The resource was intentionally removed and will not return.
422	Unprocessable Entity	The request was well-formed but is semantically invalid.
429	Too Many Requests	The client is rate-limited; see the Retry-After header.

5xx Server Error

The server failed to fulfil a valid request.

Code	Name	Meaning
500	Internal Server Error	A generic, unexpected server-side failure.
501	Not Implemented	The server does not support the functionality required.
502	Bad Gateway	An upstream server returned an invalid response.
503	Service Unavailable	The server is overloaded or down for maintenance.
504	Gateway Timeout	An upstream server did not respond in time.
511	Network Authentication Required	The client must authenticate to gain network access (captive portals).

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HTTP Status CodesHTTP Codes

Complete HTTP status code reference — every code from 100 to 511 with its meaning