500 Internal Server Error

The 500 error hides details from the client. Check your server logs for the actual error message and stack trace.

# View recent logs
heroku logs --tail
journalctl -u myapp -n 100
pm2 logs

# Enable request logging in Express
app.use(morgan("combined"))

Catch all uncaught exceptions and unhandled rejections to return meaningful error responses instead of crashing.

// Express global error handler
app.use((err, req, res, next) => {
  console.error(err.stack)
  res.status(err.status || 500).json({
    error: process.env.NODE_ENV === "production"
      ? "Internal Server Error"
      : err.message
  })
})

// Catch unhandled rejections
process.on("unhandledRejection", (err) => {
  console.error("Unhandled rejection:", err)
})

Ensure all required environment variables are set before the application starts.

// Startup validation
const required = ["DATABASE_URL", "JWT_SECRET", "API_KEY"]
for (const env of required) {
  if (!process.env[env]) {
    throw new Error(`Missing required env: ${env}`)
  }
}