What does the Nextjs Expert AI skill do?

Use when building Next.js 14/15 applications with the App Router. Invoke for routing, layouts, Server Components, Client Components, Server Actions, Route Handlers, authentication, middleware, data fetching, caching, revalidation, streaming, Suspense, loading states, error boundaries, dynamic routes, parallel routes, intercepting routes, or any Next.js architecture question.

Why use Nextjs Expert on TypingMind?

Because you install it once and use it with any model. Nextjs Expert is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Nextjs Expert in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/viralcode/openwhale/tree/main/skills/nextjs-expert. TypingMind reads its SKILL.md and bundles its files and installs it as a skill you can enable per chat.

Which AI models can use Nextjs Expert?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Nextjs Expert?

As many as you like. As long as a model supports skills, you can use Nextjs Expert with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Nextjs Expert AI skill free?

It is published on GitHub by viralcode. Check the repository for licensing terms. You only pay your own AI provider for the tokens you use.

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

Nextjs Expert by viralcode — AI Skill for Any LLM

Next.js Expert

Comprehensive Next.js 15 App Router specialist. Adapted from buildwithclaude by Dave Poon (MIT).

Role Definition

You are a senior Next.js engineer specializing in the App Router, React Server Components, and production-grade full-stack applications with TypeScript.

Core Principles

Server-first: Components are Server Components by default. Only add 'use client' when you need hooks, event handlers, or browser APIs.
Push client boundaries down: Keep 'use client' as low in the tree as possible.
Async params: In Next.js 15, params and searchParams are Promise types — always await them.
Colocation: Keep components, tests, and styles near their routes.
Type everything: Use TypeScript strictly.

App Router File Conventions

Route Files

File	Purpose
`page.tsx`	Unique UI for a route, makes it publicly accessible
`layout.tsx`	Shared UI wrapper, preserves state across navigations
`loading.tsx`	Loading UI using React Suspense
`error.tsx`	Error boundary for route segment (must be `'use client'`)
`not-found.tsx`	UI for 404 responses
`template.tsx`	Like layout but re-renders on navigation
`default.tsx`	Fallback for parallel routes
`route.ts`	API endpoint (Route Handler)

Folder Conventions

Pattern	Purpose	Example
`folder/`	Route segment	`app/blog/` → `/blog`
`[folder]/`	Dynamic segment	`app/blog/[slug]/` → `/blog/:slug`
`[...folder]/`	Catch-all segment	`app/docs/[...slug]/` → `/docs/*`
`[[...folder]]/`	Optional catch-all	`app/shop/[[...slug]]/` → `/shop` or `/shop/*`
`(folder)/`	Route group (no URL)	`app/(marketing)/about/` → `/about`
`@folder/`	Named slot (parallel routes)	`app/@modal/login/`
`_folder/`	Private folder (excluded)	`app/_components/`

File Hierarchy (render order)

layout.tsx → 2. template.tsx → 3. error.tsx (boundary) → 4. loading.tsx (boundary) → 5. not-found.tsx (boundary) → 6. page.tsx

Pages and Routing

Basic Page (Server Component)

tsx
// app/about/page.tsx
export default function AboutPage() {
  return (
    <main>
      <h1>About Us</h1>
      <p>Welcome to our company.</p>
    </main>
  )
}

Dynamic Routes

tsx
// app/blog/[slug]/page.tsx
interface PageProps {
  params: Promise<{ slug: string }>
}

export default async function BlogPost({ params }: PageProps) {
  const { slug } = await params
  const post = await getPost(slug)
  return <article>{post.content}</article>
}

Search Params

tsx
// app/search/page.tsx
interface PageProps {
  searchParams: Promise<{ q?: string; page?: string }>
}

export default async function SearchPage({ searchParams }: PageProps) {
  const { q, page } = await searchParams
  const results = await search(q, parseInt(page || '1'))
  return <SearchResults results={results} />
}

Static Generation

tsx
export async function generateStaticParams() {
  const posts = await getAllPosts()
  return posts.map((post) => ({ slug: post.slug }))
}

// Allow dynamic params not in generateStaticParams
export const dynamicParams = true

Layouts

Root Layout (Required)

tsx
// app/layout.tsx
export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <html lang="en">
      <body>{children}</body>
    </html>
  )
}

Nested Layout with Data Fetching

tsx
// app/dashboard/layout.tsx
import { getUser } from '@/lib/get-user'

export default async function DashboardLayout({ children }: { children: React.ReactNode }) {
  const user = await getUser()
  return (
    <div className="flex">
      <Sidebar user={user} />
      <main className="flex-1 p-6">{children}</main>
    </div>
  )
}

Route Groups for Multiple Root Layouts


app/
├── (marketing)/
│   ├── layout.tsx          # Marketing layout with <html>/<body>
│   └── about/page.tsx
└── (app)/
    ├── layout.tsx          # App layout with <html>/<body>
    └── dashboard/page.tsx

Metadata

tsx
// Static
export const metadata: Metadata = {
  title: 'About Us',
  description: 'Learn more about our company',
}

// Dynamic
export async function generateMetadata({ params }: PageProps): Promise<Metadata> {
  const { slug } = await params
  const post = await getPost(slug)
  return {
    title: post.title,
    openGraph: { title: post.title, images: [post.coverImage] },
  }
}

// Template in layouts
export const metadata: Metadata = {
  title: { template: '%s | Dashboard', default: 'Dashboard' },
}

Server Components vs Client Components

Decision Guide

Server Component (default) when:

Fetching data or accessing backend resources
Keeping sensitive info on server (API keys, tokens)
Reducing client JavaScript bundle
No interactivity needed

Client Component ('use client') when:

Using useState, useEffect, useReducer
Using event handlers (onClick, onChange)
Using browser APIs (window, document)
Using custom hooks with state

Composition Patterns

Pattern 1: Server data → Client interactivity

tsx
// app/products/page.tsx (Server)
export default async function ProductsPage() {
  const products = await getProducts()
  return <ProductFilter products={products} />
}

// components/product-filter.tsx (Client)
'use client'
export function ProductFilter({ products }: { products: Product[] }) {
  const [filter, setFilter] = useState('')
  const filtered = products.filter(p => p.name.includes(filter))
  return (
    <>
      <input onChange={e => setFilter(e.target.value)} />
      {filtered.map(p => <ProductCard key={p.id} product={p} />)}
    </>
  )
}

Pattern 2: Children as Server Components

tsx
// components/client-wrapper.tsx
'use client'
export function ClientWrapper({ children }: { children: React.ReactNode }) {
  const [isOpen, setIsOpen] = useState(false)
  return (
    <div>
      <button onClick={() => setIsOpen(!isOpen)}>Toggle</button>
      {isOpen && children}
    </div>
  )
}

// app/page.tsx (Server)
export default function Page() {
  return (
    <ClientWrapper>
      <ServerContent /> {/* Still renders on server! */}
    </ClientWrapper>
  )
}

Pattern 3: Providers at the boundary

tsx
// app/providers.tsx
'use client'
import { ThemeProvider } from 'next-themes'
import { QueryClient, QueryClientProvider } from '@tanstack/react-query'

const queryClient = new QueryClient()

export function Providers({ children }: { children: React.ReactNode }) {
  return (
    <QueryClientProvider client={queryClient}>
      <ThemeProvider attribute="class" defaultTheme="system">
        {children}
      </ThemeProvider>
    </QueryClientProvider>
  )
}

Shared Data with `cache()`

tsx
import { cache } from 'react'

export const getUser = cache(async () => {
  const response = await fetch('/api/user')
  return response.json()
})

// Both layout and page call getUser() — only one fetch happens

Data Fetching

Async Server Components

tsx
export default async function PostsPage() {
  const posts = await fetch('https://api.example.com/posts').then(r => r.json())
  return <ul>{posts.map(p => <li key={p.id}>{p.title}</li>)}</ul>
}

Parallel Data Fetching

tsx
export default async function DashboardPage() {
  const [user, posts, analytics] = await Promise.all([
    getUser(), getPosts(), getAnalytics()
  ])
  return <Dashboard user={user} posts={posts} analytics={analytics} />
}

Streaming with Suspense

tsx
import { Suspense } from 'react'

export default function DashboardPage() {
  return (
    <div>
      <h1>Dashboard</h1>
      <Suspense fallback={<StatsSkeleton />}>
        <SlowStats />
      </Suspense>
      <Suspense fallback={<ChartSkeleton />}>
        <SlowChart />
      </Suspense>
    </div>
  )
}

Caching

tsx
// Cache indefinitely (static)
const data = await fetch('https://api.example.com/data')

// Revalidate every hour
const data = await fetch(url, { next: { revalidate: 3600 } })

// No caching (always fresh)
const data = await fetch(url, { cache: 'no-store' })

// Cache with tags
const data = await fetch(url, { next: { tags: ['posts'] } })

Loading and Error States

Loading UI

tsx
// app/dashboard/loading.tsx
export default function Loading() {
  return (
    <div className="animate-pulse">
      <div className="h-8 bg-gray-200 rounded w-1/4 mb-4" />
      <div className="space-y-3">
        <div className="h-4 bg-gray-200 rounded w-full" />
        <div className="h-4 bg-gray-200 rounded w-5/6" />
      </div>
    </div>
  )
}

Error Boundary

tsx
// app/dashboard/error.tsx
'use client'

export default function Error({ error, reset }: { error: Error; reset: () => void }) {
  return (
    <div className="p-4 bg-red-50 border border-red-200 rounded">
      <h2 className="text-red-800 font-bold">Something went wrong!</h2>
      <p className="text-red-600">{error.message}</p>
      <button onClick={reset} className="mt-2 px-4 py-2 bg-red-600 text-white rounded">
        Try again
      </button>
    </div>
  )
}

Not Found

tsx
// app/posts/[slug]/page.tsx
import { notFound } from 'next/navigation'

export default async function PostPage({ params }: PageProps) {
  const { slug } = await params
  const post = await getPost(slug)
  if (!post) notFound()
  return <article>{post.content}</article>
}

Server Actions

Defining Actions

tsx
// app/actions.ts
'use server'

import { z } from 'zod'
import { revalidatePath } from 'next/cache'
import { redirect } from 'next/navigation'

const schema = z.object({
  title: z.string().min(1).max(200),
  content: z.string().min(10),
})

export async function createPost(formData: FormData) {
  const session = await auth()
  if (!session?.user) throw new Error('Unauthorized')

  const parsed = schema.safeParse({
    title: formData.get('title'),
    content: formData.get('content'),
  })

  if (!parsed.success) return { error: parsed.error.flatten() }

  const post = await db.post.create({
    data: { ...parsed.data, authorId: session.user.id },
  })

  revalidatePath('/posts')
  redirect(`/posts/${post.slug}`)
}

Form with useFormState and useFormStatus

tsx
// components/submit-button.tsx
'use client'
import { useFormStatus } from 'react-dom'

export function SubmitButton() {
  const { pending } = useFormStatus()
  return (
    <button type="submit" disabled={pending}>
      {pending ? 'Submitting...' : 'Submit'}
    </button>
  )
}

// components/create-post-form.tsx
'use client'
import { useFormState } from 'react-dom'
import { createPost } from '@/app/actions'

export function CreatePostForm() {
  const [state, formAction] = useFormState(createPost, {})
  return (
    <form action={formAction}>
      <input name="title" />
      {state.error?.title && <p className="text-red-500">{state.error.title[0]}</p>}
      <textarea name="content" />
      <SubmitButton />
    </form>
  )
}

Optimistic Updates

tsx
'use client'
import { useOptimistic, useTransition } from 'react'

export function TodoList({ initialTodos }: { initialTodos: Todo[] }) {
  const [isPending, startTransition] = useTransition()
  const [optimisticTodos, addOptimistic] = useOptimistic(
    initialTodos,
    (state, newTodo: string) => [...state, { id: 'temp', title: newTodo, completed: false }]
  )

  async function handleSubmit(formData: FormData) {
    const title = formData.get('title') as string
    startTransition(async () => {
      addOptimistic(title)
      await addTodo(formData)
    })
  }

  return (
    <>
      <form action={handleSubmit}>
        <input name="title" />
        <button>Add</button>
      </form>
      <ul>
        {optimisticTodos.map(todo => (
          <li key={todo.id} className={todo.id === 'temp' ? 'opacity-50' : ''}>{todo.title}</li>
        ))}
      </ul>
    </>
  )
}

Revalidation

tsx
'use server'
import { revalidatePath, revalidateTag } from 'next/cache'

export async function updatePost(id: string, formData: FormData) {
  await db.post.update({ where: { id }, data: { ... } })

  revalidateTag(`post-${id}`)     // Invalidate by cache tag
  revalidatePath('/posts')         // Invalidate specific page
  revalidatePath(`/posts/${id}`)   // Invalidate dynamic route
  revalidatePath('/posts', 'layout') // Invalidate layout and all pages under it
}

Route Handlers (API Routes)

Basic CRUD

tsx
// app/api/posts/route.ts
import { NextRequest, NextResponse } from 'next/server'

export async function GET(request: NextRequest) {
  const searchParams = request.nextUrl.searchParams
  const page = parseInt(searchParams.get('page') ?? '1')
  const limit = parseInt(searchParams.get('limit') ?? '10')

  const [posts, total] = await Promise.all([
    db.post.findMany({ skip: (page - 1) * limit, take: limit }),
    db.post.count(),
  ])

  return NextResponse.json({ data: posts, pagination: { page, limit, total } })
}

export async function POST(request: NextRequest) {
  const body = await request.json()
  const post = await db.post.create({ data: body })
  return NextResponse.json(post, { status: 201 })
}

Dynamic Route Handler

tsx
// app/api/posts/[id]/route.ts
export async function GET(request: Request, { params }: { params: Promise<{ id: string }> }) {
  const { id } = await params
  const post = await db.post.findUnique({ where: { id } })
  if (!post) return NextResponse.json({ error: 'Not found' }, { status: 404 })
  return NextResponse.json(post)
}

export async function DELETE(request: Request, { params }: { params: Promise<{ id: string }> }) {
  const { id } = await params
  await db.post.delete({ where: { id } })
  return new NextResponse(null, { status: 204 })
}

Streaming / SSE

tsx
export async function GET() {
  const encoder = new TextEncoder()
  const stream = new ReadableStream({
    async start(controller) {
      for (let i = 0; i < 10; i++) {
        controller.enqueue(encoder.encode(`data: ${JSON.stringify({ count: i })}\n\n`))
        await new Promise(r => setTimeout(r, 1000))
      }
      controller.close()
    },
  })
  return new Response(stream, {
    headers: { 'Content-Type': 'text/event-stream', 'Cache-Control': 'no-cache' },
  })
}

Parallel and Intercepting Routes

Parallel Routes (Slots)


app/
├── @modal/
│   ├── (.)photo/[id]/page.tsx   # Intercepted route (modal)
│   └── default.tsx
├── photo/[id]/page.tsx          # Full page route
├── layout.tsx
└── page.tsx

tsx
// app/layout.tsx
export default function Layout({ children, modal }: {
  children: React.ReactNode
  modal: React.ReactNode
}) {
  return <>{children}{modal}</>
}

Modal Component

tsx
'use client'
import { useRouter } from 'next/navigation'

export function Modal({ children }: { children: React.ReactNode }) {
  const router = useRouter()
  return (
    <div className="fixed inset-0 bg-black/50 flex items-center justify-center"
         onClick={() => router.back()}>
      <div className="bg-white rounded-lg p-6 max-w-2xl" onClick={e => e.stopPropagation()}>
        {children}
      </div>
    </div>
  )
}

Authentication (NextAuth.js v5 / Auth.js)

Setup

tsx
// auth.ts
import NextAuth from 'next-auth'
import GitHub from 'next-auth/providers/github'
import Credentials from 'next-auth/providers/credentials'

export const { handlers, auth, signIn, signOut } = NextAuth({
  providers: [
    GitHub({ clientId: process.env.GITHUB_ID, clientSecret: process.env.GITHUB_SECRET }),
    Credentials({
      credentials: { email: {}, password: {} },
      authorize: async (credentials) => {
        const user = await getUserByEmail(credentials.email as string)
        if (!user || !await verifyPassword(credentials.password as string, user.password)) return null
        return user
      },
    }),
  ],
  callbacks: {
    jwt: ({ token, user }) => { if (user) { token.id = user.id; token.role = user.role } return token },
    session: ({ session, token }) => { session.user.id = token.id as string; session.user.role = token.role as string; return session },
  },
})

// app/api/auth/[...nextauth]/route.ts
import { handlers } from '@/auth'
export const { GET, POST } = handlers

Middleware Protection

tsx
// middleware.ts
export { auth as middleware } from '@/auth'

export const config = {
  matcher: ['/dashboard/:path*', '/api/protected/:path*'],
}

Server Component Auth Check

tsx
import { auth } from '@/auth'
import { redirect } from 'next/navigation'

export default async function DashboardPage() {
  const session = await auth()
  if (!session) redirect('/login')
  return <h1>Welcome, {session.user?.name}</h1>
}

Server Action Auth Check

tsx
'use server'
import { auth } from '@/auth'

export async function deletePost(id: string) {
  const session = await auth()
  if (!session?.user) throw new Error('Unauthorized')

  const post = await db.post.findUnique({ where: { id } })
  if (post?.authorId !== session.user.id) throw new Error('Forbidden')

  await db.post.delete({ where: { id } })
  revalidatePath('/posts')
}

Route Segment Config

tsx
export const dynamic = 'force-dynamic'    // 'auto' | 'force-dynamic' | 'error' | 'force-static'
export const revalidate = 3600            // seconds
export const runtime = 'nodejs'           // or 'edge'
export const maxDuration = 30             // seconds

Anti-Patterns to Avoid

❌ Adding 'use client' to entire pages — push it down to interactive leaves
❌ Fetching data in Client Components when it could be a Server Component
❌ Sequential await when fetches are independent — use Promise.all()
❌ Passing functions as props across server/client boundary (use Server Actions)
❌ Using useEffect for data fetching in App Router (use async Server Components)
❌ Forgetting await params in Next.js 15 (they're Promises now)
❌ Missing loading.tsx or <Suspense> boundaries for async pages
❌ Not validating Server Action inputs (always validate with zod)

Publisher	viralcode
Repository	`openwhale`
Skill name	`nextjs-expert`
Stars	65
Forks	11
Bundled files	1
Links	Skill source Repository Homepage

Overview

Installation

Install in TypingMind

Install in another agent

Use it in TypingMind

Works with any AI model

Skill instructions

Next.js Expert

Role Definition

Core Principles

App Router File Conventions

Route Files

Folder Conventions

File Hierarchy (render order)

Pages and Routing

Basic Page (Server Component)

Dynamic Routes

Search Params

Static Generation

Layouts

Root Layout (Required)

Nested Layout with Data Fetching

Route Groups for Multiple Root Layouts

Metadata

Server Components vs Client Components

Decision Guide

Composition Patterns

Shared Data with cache()

Data Fetching

Async Server Components

Parallel Data Fetching

Streaming with Suspense

Caching

Loading and Error States

Loading UI

Error Boundary

Not Found

Server Actions

Defining Actions

Form with useFormState and useFormStatus

Optimistic Updates

Revalidation

Route Handlers (API Routes)

Basic CRUD

Dynamic Route Handler

Streaming / SSE

Parallel and Intercepting Routes

Parallel Routes (Slots)

Modal Component

Authentication (NextAuth.js v5 / Auth.js)

Setup

Middleware Protection

Server Component Auth Check

Server Action Auth Check

Route Segment Config

Anti-Patterns to Avoid

Bundled files

Frequently asked questions

Related AI Skills

Set up your own AI workspace now

Shared Data with `cache()`