HTTP Status Codes

HTTP Status Codes

HTTP Error Code List: HTTP Status Codes indicate whether a specific HTTP request has been completed successfully. Responses are grouped into five classes namely

  • Informational responses
  • Successful responses
  • Redirects
  • Client errors
  • Servers errors

Know more about HTTP Request, HTTP Verbs or HTTP Methods and its functions in responses and requests.

Error Code

1xx Information Responses

This class of status code means a temporary response, consisting notably of the Status-Line and optional headers, and is eliminated by an empty line. Since HTTP/1.0 did not specify any 1xx status codes, servers must not[note 1] transfer a 1xx response to an HTTP/1.0 client but under experimental circumstances.

100 Continue

The temporary response indicates that everything so far is OK and that the client should continue with the same request or ignore it if it is already finished.

101 Switching Protocol

The code is sent in response to an upgrade request by the client through an upgrade header. It indicates that the server is switching to a different protocol. It was introduced to allow migration to an incompatible protocol version and is not in common use.

102 Processing

This code intimates that the server has received and is processing the request, but no response is available yet. This restricts the client from timing out and assuming the request was lost.

2xx Successful Responses

This class of status codes means the action asked by the client was accepted, understood and processed successfully.

200 OK

The HTTP 200 OK is the most common return for successful HTTP requests. Simply the request has been received, understood and is being processed successfully.

201 Created

The HTTP 201 means the request by the client is succeeded, and a new resource has been created in result of it.

202 Accepted

The HTTP 201 Accepted Code means the request has been received but not yet acted upon. It is a non-committal operation, meaning that there is no way in HTTP to resend an asynchronous response. It is subjected for cases where another process or server handles the request, or for batch processing.

203 Non-Authoritative Information

The HTTP 203 Status Code means that the client request was successful, but the returned meta-information set is not exactly as set from the origin server. Except for this condition, 200 OK response should be preferred instead of this response.

204 No Content

The HTTP 204 Status Code means that the server has successfully processed the client request but doesn’t have any additional content to return the user. The user-agent may update its cached headers for this resource with the new ones.

205 Reset Content

The HTTP 205 Reset Content means that the server has fulfilled the request and the user should reset the document view to the original state which caused the request to be sent.

206 Partial Content

The HTTP 206 Partial Content means that the server has fulfilled the request partially that is the GET request of the resource. It is commonly used in caching tools where the user request for only the part of the page and just that section is returned.

207 Multi-Status (WebDAV; RFC 4918)

208 Already Reported (WebDAV; RFC 5842)

226 IM Used (RFC 3229)

3xx Redirection messages

This class of status code means the client must take extra action to complete the request. Several of these status codes used in URL redirection. A user agent may carry out the further action with no user interaction only if the system utilised in the second request is GET or HEAD. A user may automatically redirect a request. A user agent should detect and interrupt to prevent cyclical redirects.

300 Multiple Choice

The request has more than one possible responses. User-agent or user should choose one of them. There is no standardised way to choose one of the responses.

301 Moved Permanently

The HTTP 301 Moved Permanently status code means that the user requested location has been moved permanently to a new location. Further requests to the URL ought to be redirected to the new or enclosed URL.

302 Found

The HTTP 302 Found Status Code means that the user requested URL has been altered with another URL. New changes in the URI might be made in the future. Therefore, the same URI should be used by the client for future requests.

303 See Other

The HTTP Error 303 See Other means that the user requested URL is residing at a specific URL and need to be retrieved from there with a GET request.

304 Not Modified

This is used for caching purposes. It is telling to client that response has not been modified. So, client can continue to use same cached version of response.

305 Use Proxy

This means requested response must be accessed by a proxy. This response code is not largely supported because security reasons.

306 Unused

This response code is no longer used, it is just reserved currently. It was used in a previous version of the HTTP 1.1 specification.

307 Temporary Redirect

The HTTP 307 Temporary Redirect means that the request URL temporarily resides under a different URL. The server sent this response to the directing client to get a requested resource to another URI with the same method that used prior request.

308 Temporary Redirect

This means that the resource is now permanently located at another URI, specified by the Location: HTTP Response header. This has the same semantics as the 301 Moved Permanently HTTP response code, with the exception that the user agent must not change the HTTP method used: if a POST was used in the first request, a POST must be used in the second request.

4xx Client Error responses

This class of status code is reserved for conditions in which the client seems to have erred.

400 Bad Request

The 400 Bad Request means that the server could not or will understand or process the request due to invalid syntax.

401 Unauthorized

The 401 Error means more authentication is needed from the client to get requested response.

402 Payment Required

This response code is reserved for future use. Initial aim for creating this code was using it for digital payment systems however this is not used currently.

403 Forbidden

The HTTP 403 Forbidden means that the server understood the request but refuses to process or respond to it.

404 Not Found

The “Not Found” Error or the 404 Error indicates that the system or the client can contact the server whereas the server is not able to contact the system or client in return.

405 Method Not Allowed

The request method is known by the server but has been disabled and cannot be used. The two mandatory methods, GET and HEAD, must never be disabled and should not return this error code.

406 Not Acceptable

This response is sent when the web server, after performing server-driven content negotiation, doesn’t find any content following the criteria given by the user agent.

407 Proxy Authentication Required

This is similar to 401 but authentication is needed to be done by a proxy.

408 Request Timeout

This response is sent on an idle connection by some servers, even without any previous request by the client. It means that the server would like to shut down this unused connection. This response is used much more since some browsers, like Chrome or IE9, use HTTP pre-connection mechanisms to speed up surfing (see bug 881804, which tracks the future implementation of such a mechanism in Firefox). Also note that some servers merely shut down the connection without sending this message.

409 Conflict

This response would be sent when a request conflict with current state of server.

410 Gone

This response would be sent when requested content has been deleted from server.

411 Length Required

Server rejected the request because the Content-Length header field is not defined and the server requires it.

412 Precondition Failed

The client has indicated preconditions in its headers which the server does not meet.

413 Payload Too Large

Request entity is larger than limits defined by server; the server might close the connection or return an Retry-After header field.

414 URI Too Long

The URI requested by the client is longer than the server is willing to interpret.

415 Unsupported Media Type

The media format of the requested data is not supported by the server, so the server is rejecting the request.

416 Requested Range Not Satisfiable

The range specified by the Range header field in the request can’t be fulfilled; it’s possible that the range is outside the size of the target URI’s data.

417 Expectation Failed

This response code means the expectation indicated by the Expect request header field can’t be met by the server.

418 I’m a teapot (RFC 2324)

421 Misdirected Request

The request was directed to a server that is not able to produce a response. This can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI.

422 Unprocessable Entity (WebDAV; RFC 4918)

The HTTP 422 Unprocessable Entity means the request by the user client is perfect but was unable to process due to semantic errors.

423 Locked (WebDAV; RFC 4918)

424 Failed Dependency (WebDAV; RFC 4918)

426 Upgrade Required

The server refuses to perform the request using the current protocol but might be willing to do so after the client upgrades to a different protocol. The server MUST send an Upgrade header field in a 426 response to indicate the required protocol(s) (Section 6.7 of [RFC7230]).

428 Precondition Required

The origin server requires the request to be conditional. Intended to prevent “the ‘lost update’ problem, where a client GETs a resource’s state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.

429 Too Many Requests

The user has sent too many requests in a given amount of time (“rate limiting”).

431 Request Header Fields Too Large

The server is unwilling to process the request because its header fields are too large. The request MAY be resubmitted after reducing the size of the request header fields.

451 Unavailable For Legal Reasons

The user requests an illegal resource, such as a web page censored by a government.

5xx Server Error responses

The server failed to fulfil a possibly valid request. These response codes apply to any request method.

500 Internal Server Error

Also called as the ‘catch-all’ error generated by the server, which means that the server has encountered an unexpected condition preventing git from fulfilling the user request.

502 Bad Gateway

The server while being a gateway or proxy to fulfil the request by the client to access the requested URL received an invalid response from the upstream server it accessed in an attempt to fulfil the request.

503 Service Unavailable

The site has met the maximum simultaneous connections or visitors and the temporary overloading to handle the HTTP requests may lead to the HTTP 503 Error.

504 Gateway Timeout

The server did not receive a timely response from the server it was accessing to load the web page request by the user.

505 HTTP Version Not Supported

The HTTP version used in the request is not supported by the server.

506 Variant Also Negotiates

The server has an internal configuration error: Transparent content negotiation for the request results in a circular reference.

507 Variant Also Negotiates

The server has an internal configuration error. The chosen variant resource is configured to engage in transparent content negotiation itself and is therefore not a proper end point in the negotiation process.

508 Loop Detected (WebDAV; RFC 5842)

510 Not Extended (RFC 2774)

511 Network Authentication Required

The 511 status code indicates that the client needs to authenticate to gain network access.

Unofficial Error Code List

These codes are not defined in any RFC but are used by 3rd-party services to provide RESTful error responses.

103 Checkpoint

420 Method Failure (Spring Framework)

420 Enhance Your Calm (Twitter)

450 Blocked by Windows Parental Controls (Microsoft)

498 Invalid Token (Esri)

499 Token Required (Esri)

499 Request forbidden by antivirus

509 Bandwidth Limit Exceeded (Apache Web Server/cPanel)

530 Site is frozen

Internet Information Services Error Code List

IIS expands 4xx error space to signal errors.

449 Retry With

451 Redirect

444 No Response

Nginx Error Code List

The Nginx web server software extends the 4xx error space to indicate issues with the client’s request. These codes used for only logging purposes. No actual response is sent with these codes.

495 SSL Certificate Error

496 SSL Certificate Required

497 HTTP Request Sent to HTTPS Port

499 Client Closed Request

CloudFlare Error Code List

CloudFlare’s reverse proxy service expands the 5xx series of errors space to signal issues with the origin server.

520 Unknown Error

521 Web Server Is Down

522 Connection Timed Out

523 Origin Is Unreachable

524 A Timeout Occurred

525 SSL Handshake Failed

526 Invalid SSL Certificate