HTTP Status Codes Guide

Introduction

This guide provides an overview of HTTP status codes, their meanings, and their use in web development. HTTP status codes are three-digit numbers returned by web servers to indicate the result of a client's request. They are grouped into different classes, each with its own set of codes. Understanding these codes is essential for troubleshooting and building robust web applications.

Table of Contents

1. [1xx - Informational]
2. [2xx - Success]
3. [3xx - Redirection]
4. [4xx - Client Error]
5. [5xx - Server Error]

1xx - Informational

These status codes indicate that the client's request was received and understood, and further action is required.

• 100 Continue: The server is requesting the client to continue sending the request body.
• 101 Switching Protocols: The server has agreed to switch protocols.
• 102 Processing: The server is processing the request but has not yet completed it.
• 103 Early Hints: The server returns some response headers before the final HTTP message.

2xx - Success

These codes indicate that the client's request was successful.

• 200 OK: Standard response for successful HTTP requests.
• 201 Created: The request resulted in the creation of a new resource.
• 202 Accepted: The request has been accepted for processing but not yet completed.
• 203 Non-Authoritative Information: The request is successful, but the content has been modified by a proxy.
• 204 No Content: The server successfully processed the request without returning any content.
• 205 Reset Content: The server indicates to reinitialize the document view.
• 206 Partial Content: The server delivers only part of the resource due to a range header.
• 207 Multi-Status: An XML message with multiple separate response codes.
• 208 Already Reported: Members of a DAV binding have already been enumerated.
• 226 IM Used: The server has fulfilled a request, and the response is a representation of the result.

3xx - Redirection

These codes indicate that the client needs to take additional action to complete the request.

• 300 Multiple Choices: Indicates multiple options for the resource.
• 301 Moved Permanently: Requests should be directed to the given URI.
• 302 Found: Redirect to another URL (industry practice may contradict this).
• 303 See Other: The response can be found under another URI using a GET method.
• 304 Not Modified: The resource has not been modified since the specified version.
• 305 Use Proxy: The requested resource is available through a proxy.
• 307 Temporary Redirect: The request should be repeated with another URI.
• 308 Permanent Redirect: The request should be repeated using another URI.

4xx - Client Error

These codes indicate that there was a client error, such as a malformed request.

• 400 Bad Request: The server cannot process the request due to a client error.
• 401 Unauthorized: Authentication is required, and it has failed or not been provided.
• 402 Payment Required: Reserved for future use.
• 403 Forbidden: The request was valid, but the server refuses action.
• 404 Not Found: The requested resource could not be found.
• 405 Method Not Allowed: The request method is not supported for the resource.
• 406 Not Acceptable: The requested resource can't generate content according to the request's Accept headers.
• 407 Proxy Authentication Required: The client must authenticate itself with the proxy.
• 408 Request Timeout: The server timed out waiting for the request.
• 409 Conflict: Indicates that the request couldn't be processed due to a conflict.
• 410 Gone: The requested resource is no longer available.
• 411 Length Required: The request didn't specify its content length.
• 412 Precondition Failed: The server doesn't meet one of the request's preconditions.
• 413 Payload Too Large: The request is too large for the server.
• 414 URI Too Long: The URI provided was too long for the server to process.
• 415 Unsupported Media Type: The request entity has an unsupported media type.
• 416 Range Not Satisfiable: The client requested a portion of the file that the server can't supply.
• 417 Expectation Failed: The server can't meet the requirements of the Expect request-header field.
• 418 I'm a Teapot: The server refuses to brew coffee with a teapot.
• 421 Misdirected Request: The request was directed at a server that can't produce a response.
• 422 Unprocessable Entity: The request was well-formed but had semantic errors.
• 423 Locked: The resource being accessed is locked.
• 424 Failed Dependency: The request failed due to a previous request's failure.
• 425 Too Early: The server is unwilling to risk processing a potentially replayed request.