nextjs

In Next.js 15+, params and searchParams are Promises that must be awaited. Type them as Promise<{ slug: string }> and await them in pages, layouts, route handlers, and generateMetadata, or use React's use() hook in synchronous components.

This error occurs when a package using browser APIs runs in a Server Component. Fix it by using dynamic import with ssr: false, wrapping usage in a client component, or adding the package to serverExternalPackages in next.config.js.

Use Server Actions for mutations triggered from your UI, such as form submissions, since they offer type safety and progressive enhancement. Use Route Handlers for external webhooks, public REST APIs, and third-party integrations.

Parallel route slots like @modal require a default.tsx file that returns null. Without it, Next.js cannot determine what to render in the slot during hard navigation, causing a 404 on refresh.

No, the metadata object and generateMetadata function only work in Server Components. Remove 'use client' from the page, move client logic into child components, or define metadata in a parent Server Component layout.

Set output: 'standalone' in next.config.js for a minimal Docker build. For multi-instance ISR, configure a custom cacheHandler backed by Redis or S3, since the default filesystem cache is not shared between instances.