{
  "id": 4583317,
  "title": "Observability in the Next.js App Router: Field Notes on instrumentation.ts, onRequestError, and the Trace That Leaked Across Requests",
  "url": "https://urgent.news/2026/08/31/observability-in-the-next-js-app-router-field-notes-on",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-08-31T06:00:08.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/ahmed_mahmoud360/observability-in-the-nextjs-app-router-field-notes-on-instrumentationts-onrequesterror-and-the-3ke3"
  },
  "original_language": "en",
  "account": null,
  "summary": "Next.js's instrumentation.ts file and its onRequestError hook give the App Router real distributed tracing and centralized error reporting, but Vercel Fluid Compute reusing one warm instance across concurrent requests means any request state stored outside OpenTelemetry's own context propagation — a module-level variable, a naive \"current request\" global — leaks between unrelated users'…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 2,
    "also_reported_by": [
      {
        "outlet": "Dev.to",
        "title": "How to Accelerate Next.js App Router API Routes by 10x",
        "url": "https://urgent.news/2026/08/29/how-to-accelerate-next-js-app-router-api-routes-by-10x",
        "published": "2026-08-29T04:39:18.000Z"
      }
    ]
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}