Monitoring, Logging & Incident Response

You Cannot Fix What You Cannot See

Launching an application without monitoring is like flying blind. You won't know about errors until users complain. You won't know the cause until you dig through server logs. You won't know the impact until the damage is done.

Monitoring and observability are not optional — they are part of the definition of "production-ready."

Monitoring Categories

Uptime Monitoring — Is the application responding? Tools: UptimeRobot (free), Better Uptime, Pingdom. These check your URL every 30 seconds and send alerts when it stops responding.

Error Monitoring — When errors occur, who gets notified? Sentry is the industry standard. It captures exceptions, groups them by root cause, and sends alerts.

Performance Monitoring — Is the application fast? Vercel Analytics, New Relic, Datadog. Track Core Web Vitals, API response times, database query performance.

Security Monitoring — Is the application being attacked? Rate limit violations, authentication failures, unusual traffic patterns.

Health Check Endpoints

Every production application should expose a health check endpoint that checks database connectivity and other dependencies, returning 200 if healthy and 503 if degraded.

Incident Response Basics

When something breaks in production, follow this process:

1. Detect — Monitoring alert fires, or user reports an issue
2. Triage — How many users affected? Is it total outage or partial? What's the error?
3. Communicate — Notify stakeholders
4. Fix — Implement fix or rollback to previous deployment
5. Verify — Confirm the fix resolves the issue
6. Postmortem — Document what happened, why, how it was fixed, and how to prevent recurrence

Key Takeaways

• Uptime monitoring, error monitoring, and performance monitoring are the three pillars of production observability
• Sentry captures, groups, and alerts on exceptions — integrate it before you launch
• Health check endpoints allow uptime monitors to detect deep failures
• Structured JSON logs are queryable and aggregatable
• Incident response is a process: detect → triage → communicate → fix → verify → postmortem