HTTP Response Status Codes: Server Error (500–599) — Grow Together By Sharing Knowledge

Sandeep Agrawal
3 min readAug 8, 2023

HTTP response status codes are an integral part of web communication, providing valuable information about the outcome of a client’s request.

In our previous blog posts, we explored Informational Responses (100–199), Successful Responses (200–299), Redirection Responses (300–399), and Client Error Responses (400–499). These codes covered various scenarios, from establishing communication to handling successful requests and client-side errors.

Now, let’s delve into the final class of HTTP response status codes — Server Error Responses (500–599). These codes indicate that the server failed to fulfill a valid request. Join us as we examine each of these server error responses, understanding their meanings and possible resolutions.

Table: HTTP Response Status Codes — Server Error Responses HTTP 5xx Status Codes (Server Error Responses)

500 Internal Server Error

  • Description: A generic error message indicating that something unexpected happened on the server. This status code is often a catch-all for server-side errors that do not have a more specific code.
  • Example: HTTP/1.1 500 Internal Server Error

501 Not Implemented

  • Description: The server does not support the functionality required to fulfill the request. This typically occurs when the server lacks the capability to process the requested method (e.g., GET, POST, PUT).
  • Example: HTTP/1.1 501 Not Implemented

502 Bad Gateway

  • Description: The server acting as a gateway or proxy received an invalid response from an upstream server while trying to fulfill the request.
  • Example: HTTP/1.1 502 Bad Gateway

503 Service Unavailable

  • Description: The server is not ready to handle the request. Common reasons include server maintenance, overloading, or temporary unavailability of resources.
  • Example: HTTP/1.1 503 Service Unavailable

504 Gateway Timeout

  • Description: The server acting as a gateway or proxy did not receive a timely response from the upstream server.
  • Example: HTTP/1.1 504 Gateway Timeout

505 HTTP Version Not Supported

  • Description: The server does not support the HTTP protocol version used in the request.
  • Example: HTTP/1.1 505 HTTP Version Not Supported

506 Variant Also Negotiates

  • Description: The server has an internal configuration error, and the requested variant is configured to engage in transparent content negotiation.
  • Example: HTTP/1.1 506 Variant Also Negotiates

507 Insufficient Storage

  • Description: The server is unable to store the representation needed to complete the request.
  • Example: HTTP/1.1 507 Insufficient Storage

508 Loop Detected

  • Description: The server detected an infinite loop while processing the request.
  • Example: HTTP/1.1 508 Loop Detected

510 Not Extended

  • Description: The server requires further extensions to fulfill the request.
  • Example: HTTP/1.1 510 Not Extended

511 Network Authentication Required

  • Description: The client must authenticate to gain network access. This status code is primarily used on wireless networks that require login credentials.
  • Example: HTTP/1.1 511 Network Authentication Required

Server error responses (status codes 500–599) indicate that something went wrong on the server side, and the request could not be completed as expected. These errors can result from various issues, such as server misconfigurations, software bugs, or insufficient server resources. When handling these responses, developers should strive to provide informative error messages, enabling users to understand the problem and take appropriate action.

In conclusion, understanding HTTP response status codes is essential for web developers to troubleshoot and debug issues effectively. With this knowledge, developers can create more robust applications and provide a smoother user experience.

We hope you found this series on HTTP response status codes informative and helpful. Feel free to use this guide as a reference in your future web development endeavors. Happy coding!

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Originally published at on August 8, 2023.