How to Monitor Auth0: Login Failures, Callback Errors, and Uptime

Auth0 Monitoring Essentials

Auth0 is your app's front door. When it's slow or unavailable, users can't log in.

Log Auth Events

app.use((err, req, res, next) => {
  if (err.status === 401) {
    console.error(JSON.stringify({
      event: 'auth_failure',
      status: err.status,
      path: req.path
    }));
  }
  next(err);
});

Health Check for External Monitoring

Add an unauthenticated health endpoint and monitor it with Vigilmon:

app.get('/health', (req, res) => {
  res.json({ status: 'ok', auth_domain: process.env.AUTH0_DOMAIN });
});

Also monitor your Auth0 tenant URL directly - if it returns an error, logins fail for everyone.

Callback URL Error Tracking

app.get('/callback', (req, res, next) => {
  if (req.query.error) {
    console.error(JSON.stringify({
      event: 'auth0_callback_error',
      error: req.query.error,
      description: req.query.error_description
    }));
  }
  next();
});

Alert Checklist

• Login failure rate > 5% over 5 minutes
• Auth0 tenant URL unreachable
• Callback errors spiking
• Subscribe to Auth0 status page
• External uptime monitor via Vigilmon