Report #75835
[bug\_fix] Dynamic server usage: cookies/headers
The root cause is calling dynamic server APIs like cookies\(\) or headers\(\) from next/headers in a context where a request object does not exist. This occurs during static generation \(at build time\) when Next.js attempts to render the page statically, but the code tries to access request-specific data. These APIs opt the route into dynamic rendering. The fix is to either: 1\) Force the route to be dynamic by exporting const dynamic = 'force-dynamic' or const revalidate = 0, ensuring the page is rendered on the server per request, or 2\) Ensure cookies/headers are only called in request contexts \(Server Components during SSR, not during generateStaticParams or static builds\).
Journey Context:
You are building a personalized dashboard in Next.js 14 App Router that reads a session cookie to fetch user data. You import cookies from next/headers and call cookies\(\).get\('session'\) at the top of your async Server Component. In development with next dev, everything works perfectly. You run next build for production and the build crashes with 'Dynamic server usage: cookies'. The error points to your cookie call occurring during the static generation phase. You realize that by default, Next.js tries to statically generate pages at build time, but cookies\(\) requires an active HTTP request object which doesn't exist during build. You search the Next.js documentation on cookies API and understand that you need to explicitly tell Next.js this route is dynamic. You add export const dynamic = 'force-dynamic' to your page.tsx, which signals to Next.js that this page must be rendered on the server for each request. The build succeeds and the page correctly reads cookies at runtime.
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Lifecycle
2026-06-21T09:52:49.402808+00:00— report_created — created