HTTP Status Codes

What are HTTP status codes?

HTTP (Hypertext Transfer Protocol) is a protocol used by clients and servers to transmit and exchange data. HTTP status codes are part of this communication process.

HTTP status codes are responses that a server returns at the request of a search engine. To make it simple, when you visit a website, the browser (or search engine) posts a request to the website’s server, and then the server acknowledges the browser’s request with a three-digit code: the HTTP status code.

These status codes are the communication between the browser (or search engine) and the server. They communicate whether things between the two are smooth or if something is wrong. Once you start understanding status codes and learn how to use them, it will help you diagnose site errors quickly and minimize downtime on the website. These status codes help the search engines (or browsers) and the clients to access the website. For instance, a 301 redirect, for example, will tell bots and people that a page has moved somewhere else permanently.

The three-digit status codes are divided into five classes, and each class conveys a different type of message.

  • Informational responses (100–199)
  • Successful responses (200–299)
  • Redirects (300–399)
  • Client errors (400–499)
  • Server errors (500–599)


1xx informational response

These codes indicate that that the request initiated by the browser is continuing.

100 Continue

This response indicates that everything is fine, and the client should proceed with the request and ignore the reply if the request is already executed.

101 Switching Protocols

It means that your browser has asked the server to change the protocol, and the server has complied.

102 Processing

It is an interim response to inform the customer that the server has received the full request, but no response is available yet.

103 Early Hints

This information status code indicates that the server is still loading and will send the final response with the header fields.

2xx success

These status codes indicate that the server successfully accepted the request.

200 OK

This code indicates that the request is successful.

200 OK

This is a standard code to indicates that the request is successful.

201 Created

It means that the request has been accomplished, and as a consequence, one or more new resources are being created.

202 Accepted

This code indicates that the request has been completed, but the processing is incomplete.

203 Non-Authoritative Information

It means that the request was successful, but the proxy that changed the associated payload altered to the original server’s 200 OK response

204 No Content

It indicates that the server has efficiently finished the request. Moreover, there is no additional content to send to the reply payload body.

205 Reset Content

The server complies with the request and requests that the user agent reset the “Document View,” which causes the request to be sent as received from the original server.

206 Partial Content

The server is providing only a fraction of the resources due to the range header sent by the client.

207 Multi-Status

The status code means that the message body default is an XML message containing many response codes.

208 Already Reported

It means that members of the DAV Binding have already been counted within the initial part of the Multi-Status Response and don’t seem to be re-added.

226 IM Used

It indicates that the server has completed GET’s request for resources.

3xx redirection

These codes indicate that the client browser must take further action to complete the request.

300 Multiple Choices

It indicates that the target resource has more than one representation, each with its own unique identity.

301 Moved Permanently

It means all future requests are directed to a new URL.

302 Found

It means that the requested resource has been temporarily moved to the URL provided by the local header.

303 See Other

A status response code tells you that the URL you are trying to access is redirecting you to another URL.

304 Not Modified

The code that informs your browser requested resource has not been customized since the last time you accessed it.

305 Use Proxy

It means that the resources requested by the client are only available through a proxy and that the proxy address is provided in response to the server.

306 Switch Proxy

It means that subsequent requests must use a specific proxy.

307 Temporary Redirect

It means that the requested URL has been moved to a temporary location and will return shortly.

308 Permanent Redirect

It means that the required resources have been permanently moved to another URI.

4xx client errors

These status codes indicate an error has occurred, and the client browser appears to be in error.

400 Bad Request

It means that the server cannot or will not process the request due to an apparent client error.

401 Unauthorized

It is returned by the server when the target resource does not have the correct authentication certificate.

402 Payment Required

It means that the private feed is locked because the owner of the feed subscription has expired

403 Forbidden

It means that the request contained the correct data and was understood by the server, but the server is refusing to take action.

404 Not Found

It means that the required resources could not be found but may be available in the future.


405 Method Not Allowed

This error occurs when the webserver is configured in a method that does not allow you to perform specific actions

406 Not Acceptable

The requested reserve is only capable of creating suitable content according to the accept headers.

407 Proxy Authentication Required

It means that the request isn’t enforced because it lacks valid authentication credentials for the proxy server.

408 Request Timeout

It means that the server will want to close this unused connection.

409 Conflict

It indicates that the application could not be processed due to a dispute over resources.

410 Gone

This Response Status Code indicates that the resources requested by the client have been permanently deleted.

411 Length Required

The request does not specify the length of the content, which is required from the required resources.

412 Precondition Failed

It means that the browser has added some conditions to its application header, and the server does not meet these requirements.

413 Payload Too Large

The request is more significant than the server is ready or able to execute.

414 URI Too Long

It indicates that the URI provided was too long for the server.

415 Unsupported Media Type

The request includes a media type that is not supported by servers or resources.

416 Range Not Satisfiable

Your request was for a portion of resources that the server is unable to return.

417 Expectation Failed

The server is inadequate to meet the requirements specified in the expected header field of the application.

418 I’m a teapot

This code is returned from the teapots that receive the coffee-making requests.

421 Misdirected Request

The client made the request to a server that is unable to respond.

422 Unprocessable Entity

The customer’s request contains semantic errors, and the server cannot process them.

423 Locked

This code indicates that the resource that is being accessed is locked.

424 Failed Dependency

The request failed because it relied on another request, and that request failed.

425 Too Early

This status code is sent when the server is not ready to process a request because it can be rerun.

426 Upgrade Required

Due to the contents of the application upgrade header field, the client must go to a different protocol.

428 Precondition Required

The server needs to specify the terms before processing the request.

429 Too Many Requests

The client has sent so many requests in the allotted time.

431 Request Header Fields Too Large

The server is unable to process the request because the header fields are too large.

451 Unavailable For Legal Reasons

The server operator has received a request to block access to the resources you have requested.

5xx server errors

These HTTP status codes indicate that the server cannot complete the request because the server encountered an error.

500 Internal Server Error

A standard error message, given when an unexpected situation occurred and no specific message is appropriate.

501 Not Implemented

This error shows that the server does not support the functionality required to complete the request.

502 Bad Gateway

This error code usually means that one server has received an incorrect response from another, such as when a proxy server is used.

503 Service Unavailable

The server cannot handle the request.

504 Gateway Timeout

Acting as a gateway, the server ran out of time to wait for another server to respond.

505 HTTP Version Not Supported

It is sent when the server does not support the HTTP protocol version used in the application.

506 Variant Also Negotiates

The server has an internal configuration error as the chosen resource is configured to engage in transparent content negotiation. It is therefore not a proper endpoint in the negotiation process.

507 Insufficient Storage

The server is unable to save the representation required to complete the request.

508 Loop Detected

The resource limit set by your web host has been exceeded, and the server detected an infinite loop.

510 Not Extended

The application needs further extension so that the server can complete it.

511 Network Authentication Required

This HTTP status code is sent when the network you use needs verification before sending your request to the server.

Closing Statements

HTTP status codes play a significant role in quickly communicating between clients and servers. Everyone dealing in SEO needs to know the most common ones memorized. It not only makes them much more efficient in their work but lets them diagnose issues significantly quicker.

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