What are HTTP status codes?
An HTTP status code is a server response to a browser’s request. When you visit a website, your browser sends a request to the site’s server, and the server then responds to the browser’s request with a three-digit code: the HTTP status code.
These status codes are the Internet equivalent of a conversation between your browser and the server. They communicate whether things between the two are A-okay, touch-and-go, or whether something is wrong. The first digit of each three-digit status code begins with one of five numbers, 1 through 5; you may see this expressed as 1xx or 5xx to indicate status codes in that range. Each of those ranges encompasses a different class of server response.
Common HTTP status code classes:
- 1xxs – Informational responses: The server is thinking through the request.
- 2xxs – Success! The request was successfully completed and the server gave the browser the expected response.
- 3xxs – Redirection: You got redirected somewhere else. The request was received, but there’s a redirect of some kind.
- 4xxs – Client errors: Page not found. The site or page couldn’t be reached. (The request was made, but the page isn’t valid — this is an error on the website’s side of the conversation and often appears when a page doesn’t exist on the site.)
- 5xxs – Server errors: Failure. A valid request was made by the client but the server failed to complete the request.
1xx: HTTP Informational Codes
Code | Description |
100 | Continue |
101 | Switching Protocols |
102 | Processing WebDAV |
103 | Checkpoint draft POST PUT |
122 | Request-URI too long IE7 |
2xx: HTTP Successful Codes
Code | Description |
200 | OK |
201 | Created |
202 | Accepted |
203 | Non-Authoritative Information 1.1 |
204 | No Content |
205 | Reset Content |
206 | Partial Content |
207 | Multi-Status WebDAV 4918 |
208 | Already Reported WebDAV 5842 |
226 | IM Used 3229 GET |
3xx: HTTP Redirection Codes
Code | Description |
300 | Multiple Choices |
301 | Moved Permanently |
302 | Found |
303 | See Other 1.1 |
304 | Not Modified |
305 | Use Proxy 1.1 |
306 | Switch Proxy unused |
307 | Temporary Redirect 1.1 |
308 | Permanent Redirect 7538 |
307 and 308 are similar to 302 and 301, but the new request method after redirect must be the same, as on the initial request.
4xx: HTTP Client Error Code
Code | Description |
400 | Bad Request |
401 | Unauthorized |
402 | Payment Required res |
403 | Forbidden |
404 | Not Found |
405 | Method Not Allowed |
406 | Not Acceptable |
407 | Proxy Authentication Required |
408 | Request Timeout |
409 | Conflict |
410 | Gone |
411 | Length Required |
412 | Precondition Failed |
413 | Request Entity Too Large |
414 | Request-URI Too Long |
415 | Unsupported Media Type |
416 | Requested Range Not Satisfiable |
417 | Expectation Failed |
418 | I’m a teapot 2324 |
422 | Unprocessable Entity WebDAV 4918 |
423 | Locked WebDAV 4918 |
424 | Failed Dependency WebDAV 4918 |
425 | Unordered Collection 3648 |
426 | Upgrade Required 2817 |
428 | Precondition Required draft |
429 | Too Many Requests draft |
431 | Request Header Fields Too Large draft |
444 | No Response nginx |
449 | Retry With MS |
450 | Blocked By Windows Parental Controls MS |
451 | Unavailable For Legal Reasons draft |
499 | Client Closed Request nginx |
5xx: HTTP Server Error Codes
Code | Description |
500 | Internal Server Error |
501 | Not Implemented |
502 | Bad Gateway |
503 | Service Unavailable |
504 | Gateway Timeout |
505 | HTTP Version Not Supported |
506 | Variant Also Negotiates 2295 |
507 | Insufficient Storage WebDAV 4918 |
508 | Loop Detected WebDAV 5842 |
509 | Bandwidth Limit Exceeded nostd |
510 | Not Extended 2774 |
511 | Network Authentication Required draft |
598 | Network read timeout error nostd |
599 | Network connect timeout error nostd |
WebDAV | WebDAV extension |
1.1 | HTTP/1.1 |
GET, POST, PUT, POST | For these methods only |
IE | IE extension |
MS | MS extension |
nginx | nginx extension |
2518, 2817, 2295, 2774, 3229, 4918, 5842 | RFC number |
draft | Proposed draft |
nostd | Non standard extension |
res | Reserved for future use |
unused | No more in use, deprecated |
Wikipedia was used to produce all HTTP status codes content: http://en.wikipedia.org/wiki/HTTP_status
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