5 Common HTTP Error Codes You Should Know

In the world of web development, HTTP error codes are like digital signposts sharing crucial information about the success or failure of a request. For beginners, understanding these codes is fundamental. In this guide, we’ll unravel the significance of five common errors, from the familiar “404 Not Found” to the mysterious “500 Internal Server Error.” Join us to gain insights into what these codes mean, why they matter, and how they can empower you in troubleshooting and improving your web development skills.

What HTTP Error Codes Are?

Hypertext Transfer Protocol (HTTP) is the foundation of data communication on the World Wide Web. It defines a set of codes that indicate the outcome of a request between a user’s browser and a server. These codes, known as HTTP status codes, provide valuable information about the success or failure of a request.

HTTP error codes are three-digit numbers grouped into different classes. The first digit of the code specifies the general category of response, while the subsequent two digits offer more granularity. Understanding these error codes can be crucial for web developers and administrators, as they provide insights into what went wrong during a request.

5 Common HTTP Error Codes

  • 404 Not Found: One of the most recognizable error codes, the “404 Not Found”, indicates that the requested resource is not available on the server. This often occurs when a URL is mistyped, a page is deleted, or a link is broken. Users encounter a familiar “404 error” page, signalling that the content they were looking for could not be located.
  • 500 Internal Server Error: The “500 Internal Server Error” is a generic message that suggests something has gone wrong on the server side. It could be due to misconfigurations, programming errors, or other issues preventing the server from fulfilling the request. This error is a catch-all, indicating a problem that the server cannot specifically identify.
  • 403 Forbidden: When a server returns a “403 Forbidden” error, it means that the server understands the request but the server refuses to authorize it. This may occur due to insufficient permissions or authentication issues. Users attempting to access restricted areas without proper credentials often encounter this error.
  • 401 Unauthorized: Similar to the “403 Forbidden” error, the “401 Unauthorized” status code indicates that access is denied due to a lack of proper authentication. However, in this case, the server requires the user to provide valid credentials through an authentication mechanism like a username and password.
  • 400 Bad Request: The “400 Bad Request” error signifies that the server cannot process the request due to a client error. This could be caused by malformed syntax, invalid request message framing, or deceptive request routing. It’s essential to check the request parameters and structure when troubleshooting this error.

Why Are They Important?

Understanding HTTP error codes is crucial for both developers and website administrators. These codes serve as diagnostic tools, helping identify and resolve issues efficiently. By analyzing error codes, developers can pinpoint the root cause of problems, leading to quicker troubleshooting and resolution.

For website administrators, familiarity with common error codes enhances the user experience. Customized error pages and clear communication of issues can guide users, reducing frustration and increasing the chances of retaining them on the site.


HTTP error codes play a pivotal role in web development and server management. Knowing the common errors, such as 404, 500, 403, 401, and 400, empowers developers and administrators to address issues swiftly. By leveraging this knowledge, websites can provide better user experiences, ensuring seamless navigation and interaction for visitors. As you delve into the world of web development, understanding these HTTP codes will prove invaluable in maintaining a robust and user-friendly online presence.