Nextjs Guideline: DataFetching — Fetch data in Server Components. Description: Fetch directly in async Server Components. Do: async function Page() { const data = await fetch() }. Don't: useEffect for initial data. Good Example: const data = await fetch(url). Bad Example: useEffect(() => fetch(url)). Severity: High. Docs: https://nextjs.org/docs/app/building-your-application/data-fetching.