Route used `params.id`. `params` should be awaited before using its properties

Fix it yourself

Follow the repair

1. In a server page or layout, make the function async and await params. This one edit clears the error in the overwhelming majority of cases:

   // Before (Next.js 14 style — triggers the error in 15)
   export default function Page({ params }) {
     return <h1>Post {params.id}</h1>;
   }
   
   // After — same page, awaited
   export default async function Page({ params }) {
     const { id } = await params;
     return <h1>Post {id}</h1>;
   }

   With TypeScript, the prop type changes to match: params: Promise<{ id: string }>, using your real segment names.
2. Apply the same pattern in generateMetadata. Metadata functions receive params too, and they are easy to forget because the page itself looks fixed. Make generateMetadata async and await params at its top, exactly like the page. If the error names a route but the page looks clean, the metadata function is the usual hiding place.
3. In a route handler, await the params from the context argument. Handlers receive params the same way:

   export async function GET(request, { params }) {
     const { id } = await params;
     // use id as a normal value from here on
   }

   One await, at the top, before any property is read — partial fixes, like awaiting after a synchronous read, still trip the error.
4. In a Client Component, use React's use() instead of await. Client Components cannot be declared async, so the promise is unwrapped differently:

   "use client";
   import { use } from "react";
   
   export default function Page({ params }) {
     const { id } = use(params);
     return <h1>Post {id}</h1>;
   }

   Same idea, different tool: use() reads the resolved value during render. Do not reach for useEffect-and-state workarounds here — use() is the intended pattern.
5. Give searchParams the identical treatment. Whatever you did for params, do for searchParams: await it in server components, use() it in client components, and type it as a Promise. People routinely fix one, watch the error halve, and assume something else broke — it is the same change wearing a second name tag.
6. Sweep the whole project for leftovers. Search your codebase for params. and searchParams. and check each hit sits below an await or inside use(). Next.js also ships an official codemod for this migration — npx @next/codemod@canary next-async-request-api — which rewrites the common patterns automatically; on a large upgraded project it beats hand-editing thirty files.