HTTP Response Status Codes List

When you use the internet, you’re actually talking to websites without realizing it. This talk happens through a special set of rules called HTTP, which stands for Hypertext Transfer Protocol. Imagine it like a secret code that helps your computer and websites understand each other.

So, when you ask for a web page (like clicking on a link or typing in a web address), your computer sends a message in this secret code to the computer that has the webpage you want. We call this computer the “server.” The server gets your message and then sends a reply, also in the same secret code. This reply has a special three-digit number that tells your computer what happened with your request. These numbers are known as “HTTP response status codes.”

These response codes are like a quick message from the server to your computer. They’re super important because they tell your computer if everything went well or if there was a problem. These codes help people who build websites, fix issues, and make sure you have a good experience online.

In this article, we’ll give you a big list of these response codes, explain what they mean, and talk about when and why they show up.

Understanding HTTP Response Status Codes

HTTP response status codes are three-digit numerical codes that inform the client (usually your web browser) about the outcome of a requested resource or operation. They are grouped into five classes, each with its own significance:

Informational Responses (1xx): These codes indicate that the request has been received and is being processed. They are not frequently encountered in web development, but they provide information about the status of the request. For instance, the code 100 (Continue) means that the server has received the initial part of the request and is waiting for the client to continue.

Successful Responses (2xx): These codes signify that the request was successfully received, understood, and accepted. In other words, everything went well. The most commonly encountered status code in this category is 200 (OK), which means the request was successful, and the requested resource is being returned.

Redirection Messages (3xx): When a client encounters a redirection status code, it is informed that further action needs to be taken to complete the request. The most well-known code in this class is 301 (Moved Permanently), which indicates that the requested resource has been permanently moved to a new URL.

Client Error Responses (4xx): These codes are sent by the server when the client has made an error in the request, such as requesting a non-existent resource or unauthorized access. You’ve probably encountered the 404 (Not Found) code, which is displayed when a requested resource does not exist.

Server Error Responses (5xx): When the server encounters an error while processing the request, it returns a status code from the 5xx class. The 500 (Internal Server Error) code is a common example, indicating that something went wrong on the server’s side, and it couldn’t fulfill the request.

Now, let’s dive into the comprehensive list of HTTP response status codes:

Status CodeCategoryMeaningCommon Use Cases
100Informational ResponsesContinueRarely encountered, server awaits client continuation
101Informational ResponsesSwitching ProtocolsServer switches protocols, e.g., from HTTP to WebSocket
200Successful ResponsesOKStandard response for successful requests
201Successful ResponsesCreatedIndicates the creation of a new resource
202Successful ResponsesAcceptedRequest accepted for processing but not completed
204Successful ResponsesNo ContentSuccessful request with no response body
206Successful ResponsesPartial ContentUsed for partial GET requests
300Redirection MessagesMultiple ChoicesOffers multiple options for the resource
301Redirection MessagesMoved PermanentlyIndicates permanent relocation of the resource
302Redirection MessagesFoundTemporary redirection to a different URL
304Redirection MessagesNot ModifiedInforms client that cached resource is still valid
307Redirection MessagesTemporary RedirectTemporary redirection, original URL should be used
308Redirection MessagesPermanent RedirectPermanent redirection to a new URL
400Client Error ResponsesBad RequestServer can’t understand due to malformed syntax
401Client Error ResponsesUnauthorizedAuthentication required, valid credentials needed
403Client Error ResponsesForbiddenClient lacks permission to access the resource
404Client Error ResponsesNot FoundRequested resource doesn’t exist
405Client Error ResponsesMethod Not AllowedHTTP method used is not allowed for the resource
408Client Error ResponsesRequest TimeoutThe server timed out while waiting for the client’s request.
429Client Error ResponsesToo Many RequestsClient exceeded request rate limits
500Server Error ResponsesInternal Server ErrorGeneral server error, something went wrong on the server
502Server Error ResponsesBad GatewayProxy or gateway received an invalid response from upstream
503Server Error ResponsesService UnavailableServer temporarily unable to handle the request
504Server Error ResponsesGateway TimeoutProxy or gateway didn’t receive a timely response

Common Use Cases for HTTP Response Status Codes

Now that we’ve covered the comprehensive list of HTTP response status codes, let’s explore some common scenarios where these codes come into play:

200 (OK): This is the standard response to successful HTTP queries. It’s used when the server successfully delivers the requested resource, whether it’s a web page, image, or data.

301 (Moved Permanently): When a website undergoes a redesign or restructuring, this status code is used to inform search engines and browsers that the old URL has permanently moved to a new one. It helps preserve search engine rankings and user experience.

404 (Not Found): Perhaps the most recognizable status code, 404 is displayed when a requested resource is not found on the server. This can occur due to typos in URLs or when a page has been removed.

403 (Forbidden): When a user tries to access a resource they don’t have permission to view, such as a protected admin page, the server responds with a 403 status code.

502 (Bad Gateway): This code often appears in scenarios where a proxy server or gateway is involved, and the upstream server fails to provide a valid response. It’s a sign of potential network issues.

503 (Service Unavailable): When a server is temporarily overwhelmed due to high traffic or maintenance, it returns a 503 status code. This informs clients that the server is currently unavailable but should be back soon.


HTTP response status codes are a crucial aspect of web development and the browsing experience. They provide a standardized way for servers to communicate with clients, informing them of the outcome of their requests. Understanding these codes is essential for web developers, system administrators, and anyone involved in troubleshooting website issues.

In this article, we’ve provided you with a comprehensive list of HTTP response status codes, categorized by their classes, and explained their meanings and common use cases. The next time you encounter a 404 error or wonder why a website is temporarily unavailable, you’ll have a better understanding of the HTTP response status codes at play.

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