---
package: "@opentelemetry/instrumentation-undici"
version: "^0.10.0"
tier: core
decision: approved
date: 2026-05-14
deciders: [Danijel Martinek]
adr: adr-017
filter-results:
  license: Apache-2.0
  types: native
  maintenance: active
  boundary-fit: pass
  shadow-check: pass
  eu-residency: n/a
  cve-scan: clean
  named-consumer: pass
  socketRisk: clean
verification-commands:
  - npm view @opentelemetry/instrumentation-undici license
  - npm view @opentelemetry/instrumentation-undici version
  - pnpm audit --audit-level=moderate
accepted-cves: []
---

## Filter: license

<!-- Result: Apache-2.0 -->

`npm view @opentelemetry/instrumentation-undici license` returns `Apache-2.0`. Apache-2.0 is on the allowlist.

## Filter: types

<!-- Result: native -->

`@opentelemetry/instrumentation-undici` 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 the OpenTelemetry community. The 0.10.x line is current and tracks the OTel SDK release cycle. Undici is the HTTP client used by Node.js `fetch` and Next.js server-side requests.

## Filter: boundary-fit

<!-- Result: pass -->

ADR-017 §11 explicitly enables undici auto-instrumentation in `initOtelServerNode`. Undici is the underlying client for Node.js `fetch()` calls including Next.js server components and API route fetch calls. Restricted to `core-shared/instrumentation/otel/` init paths.

## Filter: shadow-check

<!-- Result: pass -->

`@opentelemetry/instrumentation-undici` is the standard OTel undici auto-instrumentation. No competing undici span emitter is present in the workspace. It complements `instrumentation-http` (Node.js http module) for full outbound request coverage.

## Filter: eu-residency

<!-- Result: n/a -->

`@opentelemetry/instrumentation-undici` is a pure instrumentation plugin with no independent data transmission. Spans are routed through the configured OTel exporter. EU residency is governed by the exporter configuration.

## Filter: cve-scan

<!-- Result: clean -->

`pnpm audit --audit-level=moderate` reports no advisories against `@opentelemetry/instrumentation-undici` at the time of this trace.

## Filter: named-consumer

<!-- Result: pass -->

`packages/core-shared/src/instrumentation/otel/init-otel-server-node.ts` registers `UndiciInstrumentation` (ADR-017 §11). This captures outbound fetch calls from Next.js server components and API routes without manual span wrapping.

## Prompt: replaces

Manual span wrapping around `fetch()` and undici `request()` calls. Since Node.js 18+, `fetch` is built on undici, meaning `instrumentation-http` alone would miss `fetch`-based outbound calls. This plugin fills the gap.

## Prompt: migration-cost-out

Low. `UndiciInstrumentation` is registered in one init file. Removing it means disabling the plugin; outbound `fetch` calls would lose automatic spans but no code outside the init file would change.

## Prompt: alternatives-considered

1. **`instrumentation-http` alone** — Sufficient for direct `http.request()` calls but misses `fetch()`/undici calls in Next.js server components. Rejected as incomplete coverage.
2. **Manual fetch wrapper** — Wrapping every `fetch` call with span creation. Rejected: Next.js makes fetch calls internally (e.g., during RSC rendering), making exhaustive wrapping impractical.

See ADR-017 for the full decision rationale.