HTTP Status Codes Cheat Sheet

Introduction

HTTP status codes are standard response codes given by web servers to indicate the outcome of a client's request. Understanding these codes is essential for debugging and optimizing web applications. This cheat sheet provides a quick reference to the most important HTTP status codes, categorized by their response type.

HTTP Status Codes Cheat Sheet

Here's a handy cheat sheet of the most important HTTP status codes:

Category	Status Code	Description
Informational Responses	100 Continue	The server has received the request headers, and the client should proceed to send the request body.
	101 Switching Protocols	The requester has asked the server to switch protocols, and the server is acknowledging that it will do so.
	102 Processing	The server has received the request and is processing it, but no response is available yet.
Successful Responses	200 OK	The request has succeeded.
	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 was successful but the information returned may come from another source.
	204 No Content	The server successfully processed the request, but is not returning any content.
	205 Reset Content	The server successfully processed the request, and asks the requester to reset its document view.
	206 Partial Content	The server is delivering only part of the resource due to a range header sent by the client.
Redirection Messages	300 Multiple Choices	The request has more than one possible response.
	301 Moved Permanently	The requested resource has been permanently moved to a new URL.
	302 Found	The requested resource has been temporarily moved to a different URL.
	303 See Other	The response to the request can be found under another URL using the GET method.
	304 Not Modified	The resource has not been modified since the version specified by the request headers.
	307 Temporary Redirect	The requested resource has been temporarily moved to a new URL. The client should use the original request method.
	308 Permanent Redirect	The requested resource has been permanently moved to a new URL. The client should use the original request method.
Client Error Responses	400 Bad Request	The server could not understand the request due to invalid syntax.
	401 Unauthorized	The request requires user authentication.
	402 Payment Required	Reserved for future use.
	403 Forbidden	The server understands the request but refuses to authorize it.
	404 Not Found	The server can't find the requested resource.
	405 Method Not Allowed	The request method is not supported for the requested resource.
	406 Not Acceptable	The requested resource is only capable of generating content not acceptable according to the Accept headers sent in the request.
	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	The request could not be completed due to a conflict with the current state of the target resource.
	410 Gone	The requested resource 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	April Fools' joke from 1998, RFC 2324.
	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 because it depended on another request and that request failed.
	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 its header fields are too large.
	451 Unavailable For Legal Reasons	The user-agent requested a resource that cannot be legally provided.
Server Error Responses	500 Internal Server Error	The server encountered an unexpected condition that prevented it from fulfilling the request.
	501 Not Implemented	The server does not support the functionality required to fulfill the request.
	502 Bad Gateway	The server, while acting as a gateway or proxy, received an invalid response from the upstream server.
	503 Service Unavailable	The server is not ready to handle the request, usually due to temporary overloading or maintenance.
	504 Gateway Timeout	The server, while acting as a gateway or proxy, 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.
	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.

Conclusion

Understanding HTTP status codes is crucial for debugging and optimizing web applications. This cheat sheet provides a quick reference to the most important HTTP status codes, helping you to diagnose issues and improve your application's performance. Keep this guide handy to make the most of HTTP status codes in your web development.