sentry-performance-tracing

# Sentry Performance Tracing ## Overview Sentry performance monitoring captures distributed traces across your application stack, measuring latency, identifying bottlenecks, and tracking Web Vitals. The v8 SDK uses a span-based API where `Sentry.startSpan()` replaces the deprecated `startTransaction()`. Auto-instrumentation covers HTTP, database queries, and framework routes out of the box. Manual spans let you measure business-critical operations. Combined with profiling (`profilesSampleRate`), you get function-level flamegraphs attached to traces. ## Prerequisites - Sentry SDK v8+ installed (`@sentry/node` >= 8.0.0 or `sentry-sdk` >= 2.0.0) - `tracesSampleRate > 0` set in `Sentry.init()` — performance data is not collected at zero - Performance monitoring enabled in your Sentry project settings (Settings > Performance) - For distributed tracing: all participating services must have Sentry SDK initialized ## Instructions ### Step 1 — Configure Tracing and Profiling in SDK Init Set `tracesSampleRate` to control what percentage of requests generate traces. Use `tracesSampler` for dynamic, per-endpoint sampling. Add `profilesSampleRate` to attach function-level flamegraphs to sampled transactions. **TypeScript (`@sentry/node`):** ```typescript import * as Sentry from '@sentry/node'; Sentry.init({ dsn: process.env.SENTRY_DSN, tracesSampleRate: 0.2, // 20% of transactions in production // Profiling — profiles 10% of sampled transactions profilesSampleRate: 0.1,...