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docs/library-decisions/2026-05-14-@sentry/nextjs.md

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+---
+package: "@sentry/nextjs"
+version: "^10.51.0"
+tier: core
+decision: approved
+date: 2026-05-14
+deciders: [Danijel Martinek]
+adr: adr-014
+filter-results:
+  license: MIT
+  types: native
+  maintenance: active
+  boundary-fit: pass
+  shadow-check: pass
+  eu-residency: ok
+  cve-scan: clean
+  named-consumer: pass
+  socketRisk: clean
+verification-commands:
+  - npm view @sentry/nextjs license
+  - npm view @sentry/nextjs version
+  - pnpm audit --audit-level=moderate
+accepted-cves: []
+---
+
+## Filter: license
+
+<!-- Result: MIT -->
+
+`npm view @sentry/nextjs license` returns `MIT`. MIT is on the allowlist.
+
+## Filter: types
+
+<!-- Result: native -->
+
+`@sentry/nextjs` is authored in TypeScript and ships its own `.d.ts` declaration files. No separate `@types/` package is needed.
+
+## Filter: maintenance
+
+<!-- Result: active -->
+
+Actively maintained by Sentry Inc. The 10.x line sees regular releases tracking Next.js releases. Used by thousands of production Next.js apps; issue tracker shows prompt engagement.
+
+## Filter: boundary-fit
+
+<!-- Result: pass -->
+
+ADR-014 designates Sentry as the error-capture and tracing backend. The ESLint `no-restricted-imports` rule (ADR-014 §6) allowlists `@sentry/*` only within `core-shared/instrumentation/sentry/**`, the apps' `instrumentation*.{ts,mjs}` / `next.config.{mjs}` entry points, and the `core-testing/setup/no-sentry.ts` mock. Feature packages MUST NOT import `@sentry/*` directly — they consume only the vendor-neutral `ITracer`/`ILogger` interfaces.
+
+## Filter: shadow-check
+
+<!-- Result: pass -->
+
+`@sentry/nextjs` is the sole Next.js error-monitoring SDK in the workspace. No competing APM or crash-reporter library (Datadog, New Relic, Rollbar, Bugsnag) is present or proposed.
+
+## Filter: eu-residency
+
+<!-- Result: ok -->
+
+Sentry offers EU-region data residency (hosted at `de.sentry.io`). The workspace's `WEB_NEXT_SENTRY_DSN` can point to an EU-hosted project; the SDK routes all payloads to the DSN host. PII scrubbing at the OTel processor layer (ADR-017, ADR-014 §4) ensures only scrubbed data leaves the process.
+
+## Filter: cve-scan
+
+<!-- Result: clean -->
+
+`pnpm audit --audit-level=moderate` reports no advisories against `@sentry/nextjs` at the time of this trace.
+
+## Filter: named-consumer
+
+<!-- Result: pass -->
+
+`packages/core-shared/src/instrumentation/sentry/` holds the Sentry adapter pair (`SentryTracer`, `SentryLogger`). `apps/web-next/instrumentation.ts` and `apps/web-next/next.config.mjs` are the concrete Next.js-side consumers. Both are named, non-hypothetical consumers.
+
+## Prompt: replaces
+
+No prior error monitoring or distributed tracing library was in place. `@sentry/nextjs` replaces ad-hoc `console.error` logging that provided no stack context, no distributed trace correlation, and no session replay for diagnosing reproduction steps.
+
+## Prompt: migration-cost-out
+
+Moderate. The interface boundary (ADR-014 §1) limits feature-package blast radius to zero — feature code never imports `@sentry/nextjs`. Removal would require swapping the `SentryTracer`/`SentryLogger` adapter pair in `core-shared/instrumentation/sentry/` for a new adapter, updating `apps/web-next/instrumentation.ts` and `next.config.mjs`, and dropping the `WEB_NEXT_SENTRY_DSN` env var. The scope is bounded and mechanical.
+
+## Prompt: alternatives-considered
+
+1. **Datadog APM** — Stronger distributed tracing primitives, but higher cost, heavier SDK footprint, and no built-in session replay. Evaluated and deferred.
+2. **New Relic** — Enterprise-grade but requires a New Relic account and agent; no native Next.js SDK at the time of evaluation.
+3. **Direct OpenTelemetry export** — Deferred to ADR-017 for the OTel migration layer; Sentry remains the exporter via `@sentry/opentelemetry` bridge.
+
+See ADR-014 for the full decision rationale.