How to Set Up Monitoring and Alerts for Your SaaS

The first time a customer messages you "your app is down" before you knew it was down is a bad day. The second time it happens, you've damaged their trust. Monitoring is the infrastructure that tells you about problems before customers do.

1. Error Tracking with Sentry

Sentry captures every unhandled exception in your frontend and backend and alerts you in real time. Setup in Next.js takes 15 minutes. Configure Sentry to alert you via email or Slack whenever a new error occurs or an existing error spikes. Group errors by fingerprint to see how often each unique error is hitting production.

2. Uptime Monitoring

An uptime monitor checks your app's availability every 1–5 minutes and alerts you if it's down. Options: Better Uptime (free tier), Checkly, or UptimeRobot (free). Configure alerts to Slack and SMS so you're notified within minutes of an outage.

3. Performance Monitoring

Sentry also captures performance data: page load times, API response times, database query durations. Set performance budgets: "Alert if any API endpoint's p95 response time exceeds 2 seconds." This catches performance regressions before they become user-visible problems.

4. Structured Logging

Instead of console.log scattered through your code, use a structured logging library that outputs JSON. Each log entry should include: timestamp, severity, user_id (for debugging specific user issues), operation name, and duration. Store logs in a searchable service — Logtail or Axiom are affordable options.

5. Payment Failure Monitoring

Stripe's Dashboard sends email alerts for payment failures. Also set up a webhook listener for invoice.payment_failed that alerts your team in Slack immediately. A missed payment failure is direct revenue loss — it needs immediate attention.

Create Runbooks

Document what to do when each alert fires. "If Sentry alerts for X error: check Y, do Z." Runbooks turn a stressful incident into a calm procedure. They also enable team members to handle incidents without needing to wake the original developer.

Avoiding Alert Fatigue

Too many alerts are as dangerous as too few. When every minor fluctuation triggers a notification, engineers quickly start ignoring their alert channels — and miss the critical alerts buried among the noise. Start with a conservative alerting strategy: only page for issues that require immediate human action. Informational alerts (things that are worth knowing but do not need a response at 2am) should route to a daily digest, not your on-call channel. Quarterly, audit your alerts: any alert that has never triggered an action in 90 days should be deleted or demoted.