? 500 Internal Server Error

? Quick Overview

The 500 Internal Server Error is an HTTP status code indicating that the server encountered an unexpected condition and could not fulfill the request. It is a generic error message when no specific error details are exposed to the client.

? Key Concepts

Server-side error (not client fault)
Occurs when application crashes or misbehaves
No detailed error shown to users by default
Common in backend languages like PHP, Node.js, Python

? Syntax / Theory

HTTP response format for a 500 error:

? View Code Example

// HTTP response indicating internal server failure
HTTP/1.1 500 Internal Server Error
Content-Type: text/html

? Code Example(s)

? View Code Example

// Example of a PHP script causing a 500 error due to fatal error
<?php
undefinedFunction();
?>

? Live Output / Explanation

What happens?

The server fails while executing backend code. Since the error is not handled, the server responds with a 500 status code instead of normal content.

? Interactive Example

Clicking the button below simulates a server failure response. We will visually simulate what happens in the Server Logs when this error occurs.

? View Code Example

// Simulated server error using JavaScript
document.getElementById("failBtn").addEventListener("click", () => {
  // Simulate server crash logs
  printLog("[INFO] Incoming Request: GET /api/data");
  printLog("[FATAL] Uncaught ReferenceError: db is not defined");
  alert("500 Internal Server Error: Server crashed");
});

[System] Server listening on port 8080...

? Use Cases

Backend crashes due to unhandled exceptions
Database connection failures
Incorrect server configuration
Deployment issues

? Tips & Best Practices

Enable server error logs during development
Handle exceptions gracefully
Return meaningful custom error pages
Never expose stack traces in production

? Try It Yourself

Create a script that throws an exception
Check server logs for the real error
Implement custom 500 error pages