Performance monitoring tracks response times

NIST AU-2 requires that systems log events sufficient to support analysis of system performance and security posture. Without performance monitoring, latency regressions introduced by a deploy are invisible until they affect enough users to show up in support tickets. P95 response times, transaction durations, and route-level latency data are the signals that distinguish "one slow request" from "our checkout flow is degraded for everyone." This check covers the gap between uptime monitoring (is the app up?) and performance monitoring (is it fast?). A SaaS losing 20% of users at checkout because the payment route is timing out has the same revenue impact as downtime — it just takes longer to surface.

Enable performance tracing in your existing error tracking tool, or add Vercel Speed Insights for frontend metrics.

If Sentry is already configured, add tracesSampleRate to your server config:

// sentry.server.config.ts
Sentry.init({
  dsn: process.env.SENTRY_DSN,
  tracesSampleRate: 0.1 // sample 10% of transactions
})

For frontend performance (Core Web Vitals), add Vercel Speed Insights:

npm install @vercel/speed-insights

// app/layout.tsx
import { SpeedInsights } from '@vercel/speed-insights/next'
// Add <SpeedInsights /> inside your root layout's <body>

After enabling, set a Sentry performance alert for P95 latency above your SLO threshold (e.g., 2 seconds).