HTTP response status codes indicate whether a specific HTTP request has been successfully completed. The reactions are divided into five classes:

  1. Informational responses (100–199),
  2. Successful Responses (200-299),
  3. Redirects (300-99),
  4. Customer errors (400-499),
  5. And server errors (500–599).

"If you get a response that is not on this list, it is a non-standard response that is compatible with the server's software."

Informational responses

100 means continue

This interim response indicates that everything is fine so far and that the customer must continue the request or ignore the response if the request has already expired.

101 Switching Protocols

This code is sent from the client in response to the upgrade request header and represents the server switching protocol.

102 Processing(WebDAV)

This code indicates that the server has received and processed the request, but has not yet received a response.

103 initial signal

This status code is primarily intended for use with link headers, allowing the user to start preloading agent resources while generating a server response.

Successful responses

200 Okay

The request was successful. The meaning of success depends on the HTTP method:

  • Receive: The resource is received and transmitted to the message body.
  • Head: The message body has unit headers.
  • PUT or POST: The resource that describes the outcome of the action is transmitted to the message body.
  • TRACE: The message body contains the request message received by the server.

201 made

The request is successful and a new resource is created as a result. This is usually a response sent after POST requests or some PUT requests.

202 accepted

The request was received, but not yet processed. This is unacceptable because there is no way to send an asynchronous response that reflects the result of the next request over HTTP. This is for batch processing or cases where the server handles another process or server request.

203 Non-Official Information

This response code means that the returned meta-information is not available from the original server, but can be collected locally or from a third-party copy. It is mostly used to back up mirrors or other resources. The “200 OK” response is preferred to this situation, except in a specific case.

204 No Content

There is no content to send for this request, but titles may help. User-agents can update their cached title for this resource with new ones.

205 reset content

It tells the user-agent to reset the document that sends the request.

206 partial content

This response code is used when an array header is sent from the client to request only a portion of the resource.

207 Multiple Locations(WebDAV)

Multiple status codes give information about multiple sources for appropriate conditions.

208 Already Reported(WebDAV)

<dev:propstat> is used inside the response element to prevent internal members of multiple bindings from being repeated in the same collection.

226 IM Access(HTTP Delta Encoding)

The server completes the GET request for the resource and the response indicates one or more frequency-manipulated outputs applicable to the current instance.

Redirection messages

300 multiple options

There is more than one response to the request. The user-agent or user must choose one of them(There is no standard way to choose one of the responses, but HTML links are recommended for prospects so users can choose it).

301 moved permanently

The URL of the requested resource is permanently changed. A new URL will be provided in the response.

302 found

This response code means that the URI of the requested resource is temporarily changed. Further changes can be made to future URIs. Therefore, the relevant URIs should be used in the customer's future requests.

303 See Other

The server sent this response to instruct the client to receive the requested resource on another URI with the GET request.

304 not revised

It is used for caching purposes. It tells the client that the response has not been modified, so the client can continue to use the same cached version of the response.

305 Use the proxy

An earlier version of the HTTP specification was defined to indicate that the requested response was accessed by a proxy. This has been removed due to security concerns related to the proxy's in-band configuration.

306 unused

This response code is no longer used; It is only reserved. This was used in an earlier version of the HTTP/1.1 specification.

307 temporary redirects

The server requests this response to indicate to the client that the requested resource is received at another URI by the method used in the previous request. It has the same semantics as the HTTP response code found in 302, with the exception that the HTTP method used by the user agent should not change: if a post is used on the first request, the second is used on the request. Should have done it.

308 Permanent Redirects

This means that the resource is now permanently in another URI, location: HTTP response header. This is similar to a 301-driven static HTTP response code, except that the HTTP method used by the user agent should not change: If POST is used in the first request, POST is used in the second request. Necessary.

Customer error responses

400 False Request

The server could not understand the request because of invalid syntax.

401 unauthorized

Although the HTTP standard defines "unauthorized", the response is "unauthorized". Namely, the customer has to verify himself to receive the requested response.

402 payment required

This response code is reserved for future use. The initial purpose of creating this code was for digital payment systems, but this status code is rarely used and there are no standard meetings.

403 forbidden

The client does not have access to content; This is unauthorized, so the server refused to provide the requested resource. Unlike 401, the client knows the identity of the client.

404 Not found

The server could not find the requested resource. This means that the URL is not detected in the browser. In an API, this means that the endpoint is valid but there are no resources. Servers can send this response instead of 403 to hide the presence of resources from unauthorized clients. This response code is consistent across the web.

405 method is not allowed

The request method is known by the server, but is disabled and not used. For example, you can reject API DELETE-ing for the resource. Both the mandatory methods of GET and HEAD are never disabled and this error code should not be returned.

406 is not acceptable

When the server discusses server-based content, this response is sent when the user agent does not find content that meets the criteria set by the user.

407 Proxy authentication required

This is similar to 401 but requires authentication by proxy.

408 request timeout

This response is sent by passive connections through some servers, without the client's previous request. The server wants to close this unused connection. Since some browsers like Chrome, Firefox 27+, or IE9 use this response too much, use HTTP pre-connection mechanisms to speed up surfing. Note that some servers only close the connection without sending this message.

409 conflict

This response is sent when the request hits the current state of the server.

410 is gone

This response is sent when the requested content is permanently deleted from the server without a forwarding address. Users are expected to delete their cache and resource links. The HTTP specification intends to use this status code for "limited time and promotion services". The API should not be forced to refer to deprecated resources with this status code.

411 length required

The server refused the request because the content-length header field was undefined and the server needed it.

412 precondition failed

The client indicates the needs of the client in its header that it cannot find.

413 The payload is very large

The request exceeds the limit defined by the entity server; The server can close the connection or retry the header field.

414 URI is too long

The URI server is ready to understand what the client wants.

415 Unsupported media type

The server does not support the media format of the requested data, so the server is rejecting the request.

416 range is not satisfactory

The category title field in the request may not conform to the specified range; The data range of the target URI is not the size.

417 hope failed

This response code means that the request has not been received from the server as indicated by the Request Header field.

418 I'm a Teapot

The server refused to try to brew coffee with Teapot.

421 wrong requested

The request has been sent to a server that cannot create a response. It is sent by an unverified server to generate a response to the combination of plans and privileges included in the requested URI.

422 Unprocessed unit(WebDAV)

The request went well but was not complied with because of semantic errors.

423 Lock(WebDAV)

The accessed resource is reduced.

424 Failed Dependencies(WebDAV)

The request failed because the previous request failed.

425 Very soon

Indicates that the server is not ready to take the risk to process the initial request.

426 Update Required

The server refused to request the use of the current protocol, but the client may be ready to do so after upgrading to a different protocol. The server sends an upgrade header in response to 426 to indicate the required protocol(s).

428 precondition required

The actual server requires a conditional request. This response is to avoid a 'lost update' problem where a client receives, modifies the status of the resource, and returns it to the server, which is modified when the third server specifies the status of the server, leading to the opposition.

429 multiple requests

The user sends too many requests in a given period of time("rate limit").

431 Request header fields are too large

The server is not ready to process the request because its header fields are too large. The request can be resubmitted after the size of the Request Title field is reduced.

451 Not available for legal reasons

The user agent requests a resource that cannot be legally provided, such as a government censored web page.

Server error response

500 Internal Server Error

The server encountered an unknown condition.

501 not implemented

The request method does not support and manage the server. The server only requires to GET and HEAD support (so this code should not be returned).

502 Bad Gateway

This error response means that when the server acts as a gateway to receive a response, it must handle the request by receiving an invalid response.

503 services not available

The server is not ready to handle the request. A down or overloaded server is a common cause for maintenance. Note that with this response, a user-friendly page explaining the problem should be sent. These responses should be used for temporary conditions and retrieved: HTTP headers, if possible, should be evaluated before the service can restart. Because these temporary status responses are not usually cached, the webmaster must also remember the caching-related headers sent by this response.

504 Gateway Timeout

This error occurs when the server acts as a gateway and does not receive a timely response.

The 505 HTTP version is not supported

The server does not support the HTTP version used in the request.

506 The version also speaks

The server has an internal configuration error: the selected version resource is configured to adhere to transparent content discussions and is therefore not an appropriate endpoint in the negotiation process.

507 Insufficient Storage(WebDAV)

This method cannot be implemented on a resource because the server cannot store the representation needed to successfully complete the request.

508 Loop Found(WebDAV)

The server detected an infinite loop while processing the request.

510 not extended

A further extension of the request is required to complete the server.

511 Network authentication required

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

So these're the HTTP response status codes you should know about, Do comment in the comment box below if you know or think I left some of the codes in this article. Stay tuned for more info like this :) See y'all later.