HTTP Status Codes Explained: Essential Guide for Developers

HTTP Status Codes Explained: Essential Guide for Developers

HTTP status codes are important for web development. They give key information about server requests. Knowing these codes can help you debug better and improve your app's user experience. In this guide, we’ll look at the different types of HTTP status codes and give examples to explain each one.

Informational Responses (1XX)

Informational status codes show that the server got the request and is still working on it.

  • 100 (Continue): The server has received the request headers, and the client should continue to send the request body.

  • 102 (Processing): The server has received the request and is working on it, but there is no response yet.

Successful Responses (2XX)

Successful status codes mean that the server got the request, understood it, and processed it successfully.

  • 200 (OK): The request was successful. This is the most common response for successful HTTP requests.

  • 201 (Created): The request was successful, and a new resource has been created.

Redirection Messages (3XX)

Redirection codes mean that the user needs to do something else to complete the request.

  • 300 (Multiple Choices): The request has more than one possible response. The user or user agent can choose one of them.

  • 301 (Moved Permanently): The requested resource has been permanently moved to a new URL provided by the Location header.

Client Error Responses (4XX)

Client error status codes mean the server couldn't process the request because of something wrong on the client's side.

  • 400 (Bad Request): The server cannot process the request because of a client error (e.g., bad request syntax).

  • 401 (Unauthorized): The request needs user authentication.

  • 404 (Not Found): The server cannot find the requested resource.

Server Error Responses (5XX)

Server error status codes mean that the server couldn't complete a valid request.

  • 500 (Internal Server Error): The server ran into an unexpected problem and couldn't complete the request.

  • 502 (Bad Gateway): The server received an invalid response from the upstream server while trying to fulfill the request.

Practical Application of HTTP Status Codes

Understanding these status codes is important for fixing and improving web applications. Here are some practical uses

  • API Integration: When integrating with APIs, handling HTTP status codes correctly ensures strong communication between services. For example, if you get a 401 Unauthorized status, prompt the user to log in again.

  • SEO: Using the right status codes like 301 (Moved Permanently) helps keep search engine rankings by properly indicating URL changes.

  • User Experience: Informing users with clear messages based on status codes (e.g., showing Page Not Found for a 404 status) improves user satisfaction and reduces frustration.



HTTP status codes are essential for web communication. By knowing and using these codes correctly, developers can build more efficient, user-friendly, and error-resistant applications. Keep this guide nearby as you work on your web projects.

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