Nextjs App Router Patterns

Seth HobsonCommunityCreated by Seth Hobson

Skill
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Software development
MIT
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From the author

Master Next.js 14+ App Router with Server Components, streaming, parallel routes, and advanced data fetching. Use when building Next.js applications, implementing SSR/SSG, or optimizing React Server Components.

— the description by Seth Hobson

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured reference for mastering the Next.js App Router. It covers essential architectural concepts including Server Components, Client Components, data fetching strategies, and routing conventions. It offers actionable patterns for implementing streaming, parallel routes, and Server Actions, helping developers transition from the Pages Router or build robust full-stack applications from the ground up.

What it does

Defines rendering modes for Server and Client components
Outlines standard file conventions for the App Router architecture
Provides patterns for data fetching and caching strategies
Demonstrates the use of Server Actions for secure mutations
Explains how to implement parallel and intercepting routes
Establishes best practices for performance and component structure

When to use it

When starting a new project using the Next.js App Router
When migrating an existing application from the Pages Router
When optimizing data fetching and implementing streaming UI
When building full-stack features using Server Actions
When needing guidance on component colocation and layout nesting

Advantages

Promotes a consistent architectural approach to Next.js development
Clarifies the boundary between server-side and client-side logic
Encourages performance-first patterns like streaming and ISR
Reduces common pitfalls by providing clear do's and don'ts

Usage examples

“How should I structure a page that needs to fetch data and show a loading state?”: The skill provides a pattern using Suspense boundaries and async Server Components to colocate data fetching, ensuring a smooth loading experience.
“What is the best way to handle form submissions in Next.js 14?”: It demonstrates the use of Server Actions, showing how to define server-side functions that handle mutations and revalidation securely.

Install

Download the skill as a ZIP:
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Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip nextjs-app-router-patterns.zip -d .agents/skills

Documentation by Seth Hobson

Next.js App Router Patterns

Comprehensive patterns for Next.js 14+ App Router architecture, Server Components, and modern full-stack React development.

When to Use This Skill

Building new Next.js applications with App Router
Migrating from Pages Router to App Router
Implementing Server Components and streaming
Setting up parallel and intercepting routes
Optimizing data fetching and caching
Building full-stack features with Server Actions

Core Concepts

1. Rendering Modes

Mode	Where	When to Use
Server Components	Server only	Data fetching, heavy computation, secrets
Client Components	Browser	Interactivity, hooks, browser APIs
Static	Build time	Content that rarely changes
Dynamic	Request time	Personalized or real-time data
Streaming	Progressive	Large pages, slow data sources

2. File Conventions

app/
├── layout.tsx       # Shared UI wrapper
├── page.tsx         # Route UI
├── loading.tsx      # Loading UI (Suspense)
├── error.tsx        # Error boundary
├── not-found.tsx    # 404 UI
├── route.ts         # API endpoint
├── template.tsx     # Re-mounted layout
├── default.tsx      # Parallel route fallback
└── opengraph-image.tsx  # OG image generation

Quick Start

// app/layout.tsx
import { Inter } from 'next/font/google'
import { Providers } from './providers'

const inter = Inter({ subsets: ['latin'] })

export const metadata = {
  title: { default: 'My App', template: '%s | My App' },
  description: 'Built with Next.js App Router',
}

export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html lang="en" suppressHydrationWarning>
      <body className={inter.className}>
        <Providers>{children}</Providers>
      </body>
    </html>
  )
}

// app/page.tsx - Server Component by default
async function getProducts() {
  const res = await fetch('https://api.example.com/products', {
    next: { revalidate: 3600 }, // ISR: revalidate every hour
  })
  return res.json()
}

export default async function HomePage() {
  const products = await getProducts()

  return (
    <main>
      <h1>Products</h1>
      <ProductGrid products={products} />
    </main>
  )
}

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.

Best Practices

Do's

Start with Server Components - Add 'use client' only when needed
Colocate data fetching - Fetch data where it's used
Use Suspense boundaries - Enable streaming for slow data
Leverage parallel routes - Independent loading states
Use Server Actions - For mutations with progressive enhancement

Don'ts

Don't pass serializable data - Server → Client boundary limitations
Don't use hooks in Server Components - No useState, useEffect
Don't fetch in Client Components - Use Server Components or React Query
Don't over-nest layouts - Each layout adds to the component tree
Don't ignore loading states - Always provide loading.tsx or Suspense

Files

ATTRIBUTION.mdAdded by AutoGineer1.0 KiB
LICENSELicence file added by AutoGineer1.0 KiB
SKILL.md3.6 KiB
references/details.md9.7 KiB

references/details.md

nextjs-app-router-patterns — detailed patterns and worked examples

Patterns

Pattern 1: Server Components with Data Fetching

// app/products/page.tsx
import { Suspense } from 'react'
import { ProductList, ProductListSkeleton } from '@/components/products'
import { FilterSidebar } from '@/components/filters'

interface SearchParams {
  category?: string
  sort?: 'price' | 'name' | 'date'
  page?: string
}

export default async function ProductsPage({
  searchParams,
}: {
  searchParams: Promise<SearchParams>
}) {
  const params = await searchParams

  return (
    <div className="flex gap-8">
      <FilterSidebar />
      <Suspense
        key={JSON.stringify(params)}
        fallback={<ProductListSkeleton />}
      >
        <ProductList
          category={params.category}
          sort={params.sort}
          page={Number(params.page) || 1}
        />
      </Suspense>
    </div>
  )
}

// components/products/ProductList.tsx - Server Component
async function getProducts(filters: ProductFilters) {
  const res = await fetch(
    `${process.env.API_URL}/products?${new URLSearchParams(filters)}`,
    { next: { tags: ['products'] } }
  )
  if (!res.ok) throw new Error('Failed to fetch products')
  return res.json()
}

export async function ProductList({ category, sort, page }: ProductFilters) {
  const { products, totalPages } = await getProducts({ category, sort, page })

  return (
    <div>
      <div className="grid grid-cols-3 gap-4">
        {products.map((product) => (
          <ProductCard key={product.id} product={product} />
        ))}
      </div>
      <Pagination currentPage={page} totalPages={totalPages} />
    </div>
  )
}

Pattern 2: Client Components with 'use client'

// components/products/AddToCartButton.tsx
'use client'

import { useState, useTransition } from 'react'
import { addToCart } from '@/app/actions/cart'

export function AddToCartButton({ productId }: { productId: string }) {
  const [isPending, startTransition] = useTransition()
  const [error, setError] = useState<string | null>(null)

  const handleClick = () => {
    setError(null)
    startTransition(async () => {
      const result = await addToCart(productId)
      if (result.error) {
        setError(result.error)
      }
    })
  }

  return (
    <div>
      <button
        onClick={handleClick}
        disabled={isPending}
        className="btn-primary"
      >
        {isPending ? 'Adding...' : 'Add to Cart'}
      </button>
      {error && <p className="text-red-500 text-sm">{error}</p>}
    </div>
  )
}

Pattern 3: Server Actions

// app/actions/cart.ts
"use server";

import { revalidateTag } from "next/cache";
import { cookies } from "next/headers";
import { redirect } from "next/navigation";

export async function addToCart(productId: string) {
  const cookieStore = await cookies();
  const sessionId = cookieStore.get("session")?.value;

  if (!sessionId) {
    redirect("/login");
  }

  try {
    await db.cart.upsert({
      where: { sessionId_productId: { sessionId, productId } },
      update: { quantity: { increment: 1 } },
      create: { sessionId, productId, quantity: 1 },
    });

    revalidateTag("cart");
    return { success: true };
  } catch (error) {
    return { error: "Failed to add item to cart" };
  }
}

export async function checkout(formData: FormData) {
  const address = formData.get("address") as string;
  const payment = formData.get("payment") as string;

  // Validate
  if (!address || !payment) {
    return { error: "Missing required fields" };
  }

  // Process order
  const order = await processOrder({ address, payment });

  // Redirect to confirmation
  redirect(`/orders/${order.id}/confirmation`);
}

Pattern 4: Parallel Routes

// app/dashboard/layout.tsx
export default function DashboardLayout({
  children,
  analytics,
  team,
}: {
  children: React.ReactNode
  analytics: React.ReactNode
  team: React.ReactNode
}) {
  return (
    <div className="dashboard-grid">
      <main>{children}</main>
      <aside className="analytics-panel">{analytics}</aside>
      <aside className="team-panel">{team}</aside>
    </div>
  )
}

// app/dashboard/@analytics/page.tsx
export default async function AnalyticsSlot() {
  const stats = await getAnalytics()
  return <AnalyticsChart data={stats} />
}

// app/dashboard/@analytics/loading.tsx
export default function AnalyticsLoading() {
  return <ChartSkeleton />
}

// app/dashboard/@team/page.tsx
export default async function TeamSlot() {
  const members = await getTeamMembers()
  return <TeamList members={members} />
}

// File structure for photo modal
// app/
// ├── @modal/
// │   ├── (.)photos/[id]/page.tsx  # Intercept
// │   └── default.tsx
// ├── photos/
// │   └── [id]/page.tsx            # Full page
// └── layout.tsx

// app/@modal/(.)photos/[id]/page.tsx
import { Modal } from '@/components/Modal'
import { PhotoDetail } from '@/components/PhotoDetail'

export default async function PhotoModal({
  params,
}: {
  params: Promise<{ id: string }>
}) {
  const { id } = await params
  const photo = await getPhoto(id)

  return (
    <Modal>
      <PhotoDetail photo={photo} />
    </Modal>
  )
}

// app/photos/[id]/page.tsx - Full page version
export default async function PhotoPage({
  params,
}: {
  params: Promise<{ id: string }>
}) {
  const { id } = await params
  const photo = await getPhoto(id)

  return (
    <div className="photo-page">
      <PhotoDetail photo={photo} />
      <RelatedPhotos photoId={id} />
    </div>
  )
}

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

Pattern 6: Streaming with Suspense

// app/product/[id]/page.tsx
import { Suspense } from 'react'

export default async function ProductPage({
  params,
}: {
  params: Promise<{ id: string }>
}) {
  const { id } = await params

  // This data loads first (blocking)
  const product = await getProduct(id)

  return (
    <div>
      {/* Immediate render */}
      <ProductHeader product={product} />

      {/* Stream in reviews */}
      <Suspense fallback={<ReviewsSkeleton />}>
        <Reviews productId={id} />
      </Suspense>

      {/* Stream in recommendations */}
      <Suspense fallback={<RecommendationsSkeleton />}>
        <Recommendations productId={id} />
      </Suspense>
    </div>
  )
}

// These components fetch their own data
async function Reviews({ productId }: { productId: string }) {
  const reviews = await getReviews(productId) // Slow API
  return <ReviewList reviews={reviews} />
}

async function Recommendations({ productId }: { productId: string }) {
  const products = await getRecommendations(productId) // ML-based, slow
  return <ProductCarousel products={products} />
}

Pattern 7: Route Handlers (API Routes)

// app/api/products/route.ts
import { NextRequest, NextResponse } from "next/server";

export async function GET(request: NextRequest) {
  const searchParams = request.nextUrl.searchParams;
  const category = searchParams.get("category");

  const products = await db.product.findMany({
    where: category ? { category } : undefined,
    take: 20,
  });

  return NextResponse.json(products);
}

export async function POST(request: NextRequest) {
  const body = await request.json();

  const product = await db.product.create({
    data: body,
  });

  return NextResponse.json(product, { status: 201 });
}

// app/api/products/[id]/route.ts
export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> },
) {
  const { id } = await params;
  const product = await db.product.findUnique({ where: { id } });

  if (!product) {
    return NextResponse.json({ error: "Product not found" }, { status: 404 });
  }

  return NextResponse.json(product);
}

Pattern 8: Metadata and SEO

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

type Props = {
  params: Promise<{ slug: string }>
}

export async function generateMetadata({ params }: Props): Promise<Metadata> {
  const { slug } = await params
  const product = await getProduct(slug)

  if (!product) return {}

  return {
    title: product.name,
    description: product.description,
    openGraph: {
      title: product.name,
      description: product.description,
      images: [{ url: product.image, width: 1200, height: 630 }],
    },
    twitter: {
      card: 'summary_large_image',
      title: product.name,
      description: product.description,
      images: [product.image],
    },
  }
}

export async function generateStaticParams() {
  const products = await db.product.findMany({ select: { slug: true } })
  return products.map((p) => ({ slug: p.slug }))
}

export default async function ProductPage({ params }: Props) {
  const { slug } = await params
  const product = await getProduct(slug)

  if (!product) notFound()

  return <ProductDetail product={product} />
}

Caching Strategies

Data Cache

// No cache (always fresh)
fetch(url, { cache: "no-store" });

// Cache forever (static)
fetch(url, { cache: "force-cache" });

// ISR - revalidate after 60 seconds
fetch(url, { next: { revalidate: 60 } });

// Tag-based invalidation
fetch(url, { next: { tags: ["products"] } });

// Invalidate via Server Action
("use server");
import { revalidateTag, revalidatePath } from "next/cache";

export async function updateProduct(id: string, data: ProductData) {
  await db.product.update({ where: { id }, data });
  revalidateTag("products");
  revalidatePath("/products");
}

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs network access

Security

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Attribution and licence

Created by

Seth Hobson

Publisher

Seth Hobson (Community)

Source

wshobson/agents · plugins/frontend-mobile-development/skills/nextjs-app-router-patterns · commit 4bde316

Licence

MIT License (redistribution allowed)

LICENSE (added by AutoGineer from LICENSE)
ATTRIBUTION.md (written by AutoGineer)

Synced

2026-11-08

AutoGineer is not affiliated with or endorsed by Seth Hobson.

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