Monitoring

The practice of continuously watching a live app or website to catch errors, slowdowns and outages, ideally before your users do. Tools track things like uptime, response time and error rates and alert you when something breaks.

Once real people depend on your product, silence is not safety. Monitoring is how you learn a payment flow is failing at 2am from an alert, not from an angry customer the next morning.

A founder sets up monitoring that sends a phone alert the moment the checkout page starts returning errors, so a broken release is caught and rolled back within minutes.