Sentry DSN Config Builder

DSN (Data Source Name) is a connection string that tells your Sentry SDK where to send error events. It contains your project ID and public key. Find it in: Sentry Dashboard → Settings → Projects → [your project] → SDK Setup → Client Keys (DSN). The DSN is safe to include in client-side code — it only allows event ingestion, not data reading.

Error sampleRate: keep at 1.0 (100%) for production — you want to capture all errors. tracesSampleRate: start at 0.1 (10%) to limit performance overhead; increase for more data. replaysSessionSampleRate: 0.1 (10%) is typical for session replay — recording all sessions is expensive. replaysOnErrorSampleRate: keep at 1.0 to always capture replays when errors occur.

Use the Sentry Next.js wizard: npx @sentry/wizard@latest -i nextjs. This creates three config files: sentry.client.config.ts (browser), sentry.server.config.ts (Node server), and sentry.edge.config.ts (Edge Runtime). The wizard also sets up source map uploading for readable stack traces. For App Router, Sentry automatically instruments Server Components and API routes.

sampleRate controls what fraction of error events are captured and sent to Sentry (default 1.0 = all errors). tracesSampleRate controls performance tracing — how many requests get traced with spans and transaction data for performance monitoring. Setting tracesSampleRate too high can add latency overhead. These are independent: you can capture 100% of errors while tracing only 5% of transactions.

Source maps are essential for production error debugging. For Vite/Next.js, use @sentry/vite-plugin or the Next.js wizard to auto-upload during build. Set SENTRY_AUTH_TOKEN as an environment variable (found in: User Settings → Auth Tokens). The auth token allows Sentry to associate uploaded source maps with releases. Never commit auth tokens to git — use environment variables or CI secrets.

Use beforeSend callback: Sentry.init({ beforeSend(event, hint) { if (event.exception?.values?.[0]?.type === 'ChunkLoadError') return null; return event; } }). Filter by URL with allowUrls/denyUrls to ignore CDN errors. Use ignoreErrors array for specific error messages or regex patterns. Set environment to filter by environment in the Sentry dashboard. Use issue filters and alerts to route important errors to the right team.