A Comprehensive Guide to HTTP Status Codes

The list of all HTTP status codes, their name, and their meaning.
1xx informational response
100 Continue
Waiting for the client to emit the body of the request.
101 Switching Protocols
The server has agreed to change protocol.
102 Processing
The server is processing the request, but no response is available yet. For WebDav.
103 Early Hints
The server returns some response headers before final HTTP message.
2xx success
200 OK
Standard response for successful HTTP requests.
201 Created
The request has been fulfilled, resulting in the creation of a new resource.
202 Accepted
The request has been accepted for processing, but the processing has not been completed.
203 Non-Authoritative Information
The request is successful but the content of the original request has been modified by a transforming proxy.
204 No Content
The server successfully processed the request and is not returning any content.
205 Reset Content
The server indicates to reinitialize the document view which sent this request.
206 Partial Content
The server is delivering only part of the resource due to a range header sent by the client.
207 Multi-Status
The message body that follows is an XML message and can contain a number of separate response codes. For WebDav.
208 Already Reported
The members of a DAV binding have already been enumerated in a preceding part of the (multistatus) response. For WebDav.
226 IM Used
The server has fulfilled a request for the resource, and the response is a representation of the result.
3xx redirection
300 Multiple Choices
Indicates multiple options for the resource that the client may follow.
301 Moved Permanently
This and all future requests should be directed to the given URI.
302 Found
Redirect to another URL. This is an example of industry practice contradicting the standard.
303 See Other
The response to the request can be found under another URI using a GET method.
304 Not Modified
Indicates that the resource has not been modified since the version specified by the request headers.
305 Use Proxy
The requested resource is available only through a proxy, the address for which is provided in the response.
306 Switch Proxy
No longer used. Originally meant "Subsequent requests should use the specified proxy."
307 Temporary Redirect
In this case, the request should be repeated with another URI; however, future requests should still use the original URI.
308 Permanent Redirect
The request and all future requests should be repeated using another URI.
4xx client error
400 Bad Request
The server cannot or will not process the request due to an apparent client error.
401 Unauthorized
Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided.
402 Payment Required
Reserved for future use. The original intention was that this code might be used as part of some form of digital cash or micropayment scheme.
403 Forbidden
The request was valid, but the server is refusing action. The user might not have the necessary permissions for a resource.
404 Not Found
The requested resource could not be found but may be available in the future.
405 Method Not Allowed
A request method is not supported for the requested resource.
406 Not Acceptable
The requested resource is capable of generating only content not acceptable according to the Accept headers sent in the request.
407 Proxy Authentication Required
The client must first authenticate itself with the proxy.
408 Request Timeout
The server timed out waiting for the request.
409 Conflict
Indicates that the request could not be processed because of conflict in the request, such as an edit conflict.
410 Gone
Indicates that the resource requested is no longer available and will not be available again.
411 Length Required
The request did not specify the length of its content, which is required by the requested resource.
412 Precondition Failed
The server does not meet one of the preconditions that the requester put on the request.
413 Payload Too Large
The request is larger than the server is willing or able to process.
414 URI Too Long
The URI provided was too long for the server to process.
415 Unsupported Media Type
The request entity has a media type which the server or resource does not support.
416 Range Not Satisfiable
The client has asked for a portion of the file, but the server cannot supply that portion.
417 Expectation Failed
The server cannot meet the requirements of the Expect request-header field.
418 I'm a teapot
The server refuses the attempt to brew coffee with a teapot.
421 Misdirected Request
The request was directed at a server that is not able to produce a response.
422 Unprocessable Entity
The request was well-formed but was unable to be followed due to semantic errors.
423 Locked
The resource that is being accessed is locked.
424 Failed Dependency
The request failed due to failure of a previous request.
425 Too Early
Indicates that the server is unwilling to risk processing a request that might be replayed.
426 Upgrade Required
The client should switch to a different protocol such as TLS/1.0.
428 Precondition Required
The origin server requires the request to be conditional.
429 Too Many Requests
The user has sent too many requests in a given amount of time.
431 Request Header Fields Too Large
The server is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.
451 Unavailable For Legal Reasons
A server operator has received a legal demand to deny access to a resource or to a set of resources that includes the requested resource.
5xx server error
500 Internal Server Error
A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.
501 Not Implemented
The server either does not recognize the request method, or it lacks the ability to fulfill the request.
502 Bad Gateway
The server was acting as a gateway or proxy and received an invalid response from the upstream server.
503 Service Unavailable
The server is currently unavailable (because it is overloaded or down for maintenance).
504 Gateway Timeout
The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.
505 HTTP Version Not Supported
The server does not support the HTTP protocol version used in the request.
506 Variant Also Negotiates
Transparent content negotiation for the request results in a circular reference.
507 Insufficient Storage
The server is unable to store the representation needed to complete the request.
508 Loop Detected
The server detected an infinite loop while processing the request.
510 Not Extended
Further extensions to the request are required for the server to fulfill it.
511 Network Authentication Required
The client needs to authenticate to gain network access.

A Comprehensive Guide to HTTP Status Codes

HTTP status codes, like a city’s traffic signals, guide the flow of data in the world of web development. They provide crucial information about the client-server communication and help to identify any potential issues. This article will delve into the world of HTTP status codes, providing a detailed overview of the different types and their meanings.

1. Introduction to HTTP Status Codes

HTTP, or HyperText Transfer Protocol, is the foundation of data communication on the World Wide Web. HTTP status codes are three-digit numbers that are returned by the server to the client to indicate the outcome of an HTTP request. Like a traffic cop directing cars, these codes inform the client about the server’s response, whether it’s a successful journey, a redirection, or an error.

Understanding HTTP status codes is vital for developers, as it aids in troubleshooting and ensures smooth data flow. The codes are divided into five classes, distinguished by the first digit: 1xx (Informational), 2xx (Successful), 3xx (Redirection), 4xx (Client errors), and 5xx (Server errors).

2. Detailed Explanation of HTTP Status Codes

Let’s dive deeper into the ocean of HTTP status codes:

  • 1xx (Informational): This class of status codes indicates a provisional response and requires the requester to continue the action. Examples include 100 (Continue), 101 (Switching Protocols), and 102 (Processing).

  • 2xx (Success): Codes beginning with ‘2’ signify that the client’s request was successfully received, understood, and accepted. Some of these are 200 (OK), 201 (Created), and 202 (Accepted).

  • 3xx (Redirection): These codes suggest that further action needs to be taken to complete the request, often in the form of a redirect. Examples include 300 (Multiple Choices), 301 (Moved Permanently), and 302 (Found).

  • 4xx (Client errors): The 4xx class of status codes is used when the request contains bad syntax or cannot be fulfilled. These include 400 (Bad Request), 401 (Unauthorized), and 404 (Not Found).

  • 5xx (Server errors): This final group of status codes indicates cases in which the server is aware that it has encountered an error or is incapable of performing the request. Examples include 500 (Internal Server Error), 501 (Not Implemented), and 502 (Bad Gateway).

3. Commonly Encountered HTTP Status Codes

While there are many HTTP status codes, developers often encounter a subset of these in their daily work. Understanding these common codes can save a lot of time and frustration. Some of these include:

  • 200 (OK): The request was successful, and the server returned the expected content.
  • 301 (Moved Permanently): The URL of the requested resource has been changed permanently. The new URL is given in the response.
  • 400 (Bad Request): The server could not understand the request due to invalid syntax.
  • 404 (Not Found): The server can not find the requested resource.
  • 500 (Internal Server Error): The server encountered an unexpected condition that prevented it from fulfilling the request.

4. Conclusion

Understanding HTTP status codes is like learning the language of the web. It allows developers to communicate effectively with servers and troubleshoot issues with ease. While this guide provides a comprehensive overview, the world of HTTP status codes is vast and constantly evolving. Keep exploring and stay updated!