Demystifying HTTP Response Status Codes

When you interact with websites or web applications, the server communicates its responses using HTTP status codes. These codes provide essential information about the outcome of a request and help developers diagnose and resolve issues. Let’s delve into the most common HTTP status codes and their meanings.

1xx Informational Responses

1. 100 Continue: The server has received the initial part of the request and hasn’t rejected it yet.
2. 101 Switching Protocols: The server is changing protocols, such as switching from HTTP to WebSocket.

2xx Success Responses

1. 200 OK: The request was successful, and the server has returned the requested resource.
2. 201 Created: The request has been fulfilled, and a new resource has been created as a result.
3. 202 Accepted: The request has been accepted for processing, but the processing has not been completed.
4. 204 No Content: The server successfully processed the request but isn’t returning any content.

3xx Redirection Messages

1. 300 Multiple Choices: Indicates multiple options for the requested resource.
2. 301 Moved Permanently: The requested resource has been permanently moved to a new URL.
3. 302 Found: The requested resource has been temporarily moved to a different URL.
4. 304 Not Modified: Indicates that the resource has not been modified since the last request.

4xx Client Error Responses

1. 400 Bad Request: The server cannot process the request due to a client error, such as malformed syntax.
2. 401 Unauthorized: The request requires user authentication.
3. 403 Forbidden: The client does not have permission to access the requested resource.
4. 404 Not Found: The requested resource could not be found on the server.

5xx Server Error Responses

1. 500 Internal Server Error: A generic error message indicating that something has gone wrong on the server.
2. 501 Not Implemented: The server does not support the functionality required to fulfill the request.
3. 502 Bad Gateway: The server received an invalid response from an upstream server.
4. 503 Service Unavailable: The server is temporarily unable to handle the request due to maintenance or overload.
5. 504 Gateway Timeout: The server did not receive a timely response from an upstream server.
6. 505 HTTP Version Not Supported: The server does not support the HTTP protocol version used in the request.

Additional Status Codes (Uncommon)

1. 451 Unavailable For Legal Reasons: The server is denying access to the resource as per legal demands.
2. 418 I’m a teapot: A humorous code indicating that the server refuses to brew coffee because it is, in fact, a teapot.

Conclusion

Understanding HTTP response status codes is essential for both developers and users. They provide valuable insights into the outcome of a request and help diagnose and troubleshoot issues effectively. By familiarizing yourself with these status codes, you can better navigate the intricacies of web development and ensure smoother user experiences.