> Building Scalable Web Applications with Next.js 15

Next.js 15 introduces groundbreaking features that revolutionize how we build modern web applications. In this comprehensive guide, we'll explore the latest capabilities and best practices.

> Getting Started with Next.js 15

First, let's create a new Next.js 15 project with the latest features:

bash.sh
COPY
npx create-next-app@latest my-app --typescript --tailwind --eslint --app
cd my-app
npm run dev

> Server Components and Client Components

One of the most significant changes in Next.js 15 is the enhanced Server Components architecture:

tsx.sh
COPY
// app/components/ServerComponent.tsx
import { Suspense } from 'react'
import { fetchUserData } from '@/lib/api'

export default async function ServerComponent({ userId }: { userId: string }) {
  const userData = await fetchUserData(userId)
  
  return (
    <div className="p-6 bg-white rounded-lg shadow-md">
      <h2 className="text-2xl font-bold mb-4">{userData.name}</h2>
      <p className="text-gray-600">{userData.email}</p>
      <Suspense fallback={<div>Loading posts...</div>}>
        <UserPosts userId={userId} />
      </Suspense>
    </div>
  )
}

> Advanced Routing with App Router

The App Router provides powerful routing capabilities:

tsx.sh
COPY
// app/dashboard/[userId]/page.tsx
interface PageProps {
  params: { userId: string }
  searchParams: { tab?: string }
}

export default function DashboardPage({ params, searchParams }: PageProps) {
  const { userId } = params
  const activeTab = searchParams.tab || 'overview'
  
  return (
    <div className="container mx-auto px-4 py-8">
      <h1 className="text-3xl font-bold mb-6">Dashboard for {userId}</h1>
      <TabNavigation activeTab={activeTab} userId={userId} />
      <TabContent tab={activeTab} userId={userId} />
    </div>
  )
}

export async function generateMetadata({ params }: PageProps) {
  const user = await fetchUserData(params.userId)
  
  return {
    title: `${user.name}'s Dashboard`,
    description: `Manage ${user.name}'s account and settings`
  }
}

> Performance Optimization Techniques

> 1. Image Optimization

tsx.sh
COPY
import Image from 'next/image'

export function OptimizedImage() {
  return (
    <Image
      src="/hero-image.jpg"
      alt="Hero Image"
      width={1200}
      height={600}
      priority
      className="rounded-lg shadow-lg"
      placeholder="blur"
      blurDataURL="data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQ..."
    />
  )
}

> 2. Dynamic Imports and Code Splitting

tsx.sh
COPY
import dynamic from 'next/dynamic'

const DynamicChart = dynamic(() => import('@/components/Chart'), {
  loading: () => <div className="animate-pulse bg-gray-200 h-64 rounded"></div>,
  ssr: false
})

export function Dashboard() {
  return (
    <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
      <DynamicChart data={chartData} />
      <MetricsCard />
    </div>
  )
}

> State Management with Zustand

For complex state management, we recommend Zustand:

tsx.sh
COPY
import { create } from 'zustand'
import { persist } from 'zustand/middleware'

interface UserStore {
  user: User | null
  setUser: (user: User) => void
  clearUser: () => void
  preferences: UserPreferences
  updatePreferences: (prefs: Partial<UserPreferences>) => void
}

export const useUserStore = create<UserStore>()(
  persist(
    (set) => ({
      user: null,
      setUser: (user) => set({ user }),
      clearUser: () => set({ user: null }),
      preferences: {
        theme: 'light',
        notifications: true,
        language: 'en'
      },
      updatePreferences: (prefs) =>
        set((state) => ({
          preferences: { ...state.preferences, ...prefs }
        }))
    }),
    {
      name: 'user-storage'
    }
  )
)

> Conclusion

Next.js 15 provides powerful tools for building scalable applications. By leveraging Server Components, the App Router, and modern optimization techniques, you can create fast, maintainable web applications that scale with your business needs.