Next.js build errorNext.js “DynamicServerError: Dynamic Server Usage”

Why the build throws DynamicServerError, and the fix

1. 01

   cookies() or headers() runs inside a timer

   “The function was called inside of a setTimeout or setInterval, causing the value to be read outside of the call stack that the context was bound to.” Next.js, DynamicServerError

   Code that reads cookies inside setTimeout or setInterval runs after the context has gone. Read the values first and pass them into the timer. This is Next.js’s corrected example.

   import { cookies } from 'next/headers'
   
   async function getCookieData() {
     const cookieStore = await cookies()
     const cookieData = cookieStore.getAll()
     return new Promise((resolve) =>
       setTimeout(() => {
         resolve(cookieData)
       }, 1000)
     )
   }
   
   export default async function Page() {
     const cookieData = await getCookieData()
     return <div>Hello World</div>
   }

2. 02

   A promise that reads cookies isn’t awaited

   “Ensure that you await Promises that invoke a function that depends on async context, otherwise the function may be called after the async operation has completed.” Next.js, DynamicServerError

   If a helper that calls cookies() or headers() is started without await, it can run after the render it belongs to has finished. We also look for helpers like getSession() or getUser() called without await on server pages, and add it.

Checked against the vendor’s docs on November 2, 2026: Next.js docs: DynamicServerError, Dynamic Server Usage; Next.js docs: Caching, route segment config.

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