/nextjs-16

name: nextjs-16
description: Use when building Next.js 16 apps — Turbopack, App Router, Cache Components, proxy.ts, v15 migration. Not for stack scaffolding (nextjs-stack) or React SPA (react-expert).
versions:
  nextjs: 16
  react: 19
user-invocable: true
references: references/installation.md, references/upgrade.md, references/project-structure.md, references/typescript.md, references/styling.md, references/app-router.md, references/routing-advanced.md, references/navigation.md, references/route-segment-config.md, references/pages-router.md, references/server-components.md, references/directives.md, references/react-19.md, references/rendering.md, references/streaming.md, references/runtime.md, references/data-fetching.md, references/forms.md, references/static-generation.md, references/cookies-headers.md, references/caching.md, references/cache-components.md, references/turbopack.md, references/react-compiler.md, references/dynamic-imports.md, references/loading-patterns.md, references/error-handling.md, references/proxy.md, references/middleware-migration.md, references/api-routes.md, references/security.md, references/metadata.md, references/metadata-files.md, references/images.md, references/fonts.md, references/scripts.md, references/third-party.md, references/analytics.md, references/instrumentation.md, references/devtools-mcp.md, references/environment.md, references/deployment.md, references/testing.md, references/config-advanced.md
related-skills: nextjs-i18n, better-auth, tailwindcss-core, solid-nextjs, nextjs-stack, nextjs-server-components, nextjs-tanstack-query

<objective> Covers Next.js 16 core framework mechanics: Turbopack (default bundler, Webpack fully removed), the App Router (nested layouts, parallel/intercepting routes, file conventions like page.tsx/layout.tsx/loading.tsx/error.tsx/not-found.tsx), Cache Components (`use cache`, `cacheTag()`, `cacheLife()`, `revalidateTag()`), `proxy.ts` (full Node.js runtime, replaces Edge middleware), and React 19 integration (View Transitions, new hooks).

Documents the critical v15→v16 breaking changes: proxy.ts replacing middleware.ts, Turbopack-only builds, `use cache` replacing Partial Prerendering, required React 19, and async `params`/`searchParams`. This skill covers core framework APIs only — for assembling a full production stack (Prisma, Better Auth, shadcn/ui, Zustand together) use nextjs-stack instead; for a pure React SPA without `next.config.*` use the react-expert skills instead. </objective>

Next.js 16 Expert

Production-ready React framework with Server Components, streaming, and Turbopack.

Agent Workflow (MANDATORY)

Before ANY implementation, spawn 3 agents in parallel, one `Agent` call each with a `name`:

1. **fuse-ai-pilot:explore-codebase** - Analyze existing routes, components, and patterns 2. **fuse-ai-pilot:research-expert** - Verify latest Next.js 16 docs via Context7/Exa 3. **mcp__context7__query-docs** - Check breaking changes v15→v16

After implementation, run **fuse-ai-pilot:sniper** for validation.

---

Overview

When to Use

• Building new React applications with server-first architecture
• Need Server Components for optimal performance and SEO
• Implementing streaming and progressive rendering
• Migrating from Next.js 14/15 to version 16
• Using proxy.ts for route protection (replaces middleware)
• Leveraging Turbopack for faster development builds

Why Next.js 16

| Feature | Benefit | |---------|---------| | Turbopack default | 2-5x faster builds, 10x faster HMR, Webpack deprecated | | Cache Components | Explicit caching with `use cache` directive | | proxy.ts | Full Node.js runtime, replaces Edge middleware | | React Compiler | Automatic memoization, no manual useMemo/useCallback | | React 19 | View Transitions, useEffectEvent, Activity component | | App Router | Nested layouts, parallel routes, intercepting routes |

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Breaking Changes from v15

Critical Migration Points

1. **proxy.ts replaces middleware.ts** - Full Node.js runtime, not Edge 2. **Turbopack ONLY** - Webpack completely deprecated and removed 3. **`use cache` directive** - Replaces Partial Prerendering (PPR) 4. **React 19 required** - New hooks and View Transitions API 5. **Async params/searchParams** - Must await dynamic route params

---

SOLID Architecture

Module-Based Structure

Pages are thin entry points importing from feature modules:

• `app/page.tsx` → imports from `modules/public/home/`
• `app/dashboard/page.tsx` → imports from `modules/auth/dashboard/`
• `modules/cores/` → Shared services, utilities, configurations

File Conventions

• **page.tsx** - Route UI component
• **layout.tsx** - Shared UI wrapper
• **loading.tsx** - Suspense loading state
• **error.tsx** - Error boundary
• **not-found.tsx** - 404 handling

---

Core Concepts

Server Components (Default)

All components are Server Components by default. Use `'use client'` directive only when needed for interactivity, hooks, or browser APIs.

Caching Strategy

• **`use cache`** - Mark async functions for caching
• **`cacheTag()`** - Tag cached data for targeted revalidation
• **`cacheLife()`** - Control cache duration (stale, revalidate, expire)
• **`revalidateTag()`** - Invalidate cached data on-demand

Data Fetching

Server Components fetch data directly. Use `fetch()` with native caching or database queries. No need for `getServerSideProps` or `getStaticProps`.

---

Reference Guide

| Need | Reference | |------|-----------| | Initial setup | [installation.md](references/installation.md), [project-structure.md](references/project-structure.md) | | Migration v15→v16 | [upgrade.md](references/upgrade.md), [middleware-migration.md](references/middleware-migration.md) | | Routing | [app-router.md](references/app-router.md), [routing-advanced.md](references/routing-advanced.md) | | Caching | [caching.md](references/caching.md), [cache-components.md](references/cache-components.md) | | Server Co