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From React App to Production-Ready Next.js: A Practical Guide to Your First Migration

A practical, step-by-step guide to migrating from Create React App (CRA) to production-ready Next.js in 2025—covering why to move, how to structure the migration, and what to watch out for.

From React App to Production-Ready Next.js: A Practical Guide to Your First Migration

If you built your application with Create React App (CRA) a few years ago, you’re not alone—and you’re also not alone if that setup is starting to feel limiting.

In 2025, Next.js has become the de facto standard for production-grade React applications, especially when you care about:

  • Performance
  • SEO and shareable pages
  • Scalability and maintainability
  • Modern full-stack capabilities

The good news: migrating from CRA to Next.js is now a well‑trodden, practical path. Many teams have already done it—sometimes with large, complex codebases—and the patterns are clear. This post will walk you through your first migration from CRA to a production-ready Next.js app, focusing on practical steps rather than theory.

Why Migrate from CRA to Next.js in 2025?

Before diving into the how, it’s worth being clear on the why.

1. Next.js is now a full-stack platform, not “just a React framework”

Next.js started as a framework for server‑rendered React. Today, it’s a full-stack platform that gives you:

  • File-based routing (no manual react-router setup)
  • Data fetching on the server (SSR, SSG, ISR)
  • API routes, server actions, and edge functions
  • Built‑in image optimization, fonts, and analytics
  • First‑class support for TypeScript and modern bundlers

For many teams, this means one unified platform instead of glueing together CRA + Express + custom SSR + Webpack config.

2. Better performance and SEO out of the box

CRA builds Single Page Applications (SPA), where everything renders on the client after JavaScript loads. That can hurt:

  • First contentful paint and core web vitals
  • SEO, since crawlers may see very little HTML without JS

Next.js ships with:

  • Server-Side Rendering (SSR) for dynamic content
  • Static Site Generation (SSG) for fast, cacheable pages
  • Incremental Static Regeneration (ISR) for hybrid approaches

Many real‑world migrations show immediate improvements in page speed, lighthouse scores, and search rankings.

3. Proven at scale

Large open-source and commercial applications have already migrated from vanilla React setups to Next.js, demonstrating:

  • The feasibility of migration, even for big codebases
  • The maintainability of Next’s conventions over time
  • The ability to gradually adopt Next.js instead of rewriting everything at once

You’re not exploring uncharted territory—you’re following a path others have validated.

Migration Strategy: Don’t Rewrite, Incrementally Adopt

The fastest way to fail a migration is to treat it as a complete rewrite. Instead, think in phases.

A practical approach:

  1. Bootstrap a new Next.js project
  2. Mirror your CRA structure in app or pages
  3. Move shared code first (components, hooks, utilities)
  4. Gradually port routes/pages
  5. Introduce server-side features (SSR/SSG, API routes) once stable
  6. Harden for production (envs, CI/CD, monitoring)

Let’s break these down.

Step 1: Set Up Your Next.js Project

From your repo root (or a new repo), run:

npx create-next-app@latest

You’ll be asked a series of questions. Common production-ready choices for 2025:

  • TypeScript: Yes
  • ESLint: Yes
  • App Router (default): Yes — this is the modern Next.js routing system
  • Tailwind (optional): Yes, if you already use it or want utility CSS

This scaffolds a fully configured Next.js app with sensible defaults.

Tip: Create it in a sibling folder (e.g. my-app-next) so you can refer to your existing CRA code during migration.

Step 2: Understand the Key Differences

Before moving files, align on these core changes.

1. Routing

  • CRA: Typically uses react-router with a custom Routes setup.
  • Next.js: Routing is file-based.
    • With the App Router, routes live in app/<route>/page.tsx.
    • Nested folders represent nested routes.

Example:

app/
  page.tsx           -> /
  dashboard/
    page.tsx         -> /dashboard
  blog/
    [slug]/
      page.tsx       -> /blog/:slug

2. Entry point

  • CRA: src/index.tsx renders <App /> into a root div.
  • Next.js: You don’t manually call ReactDOM.render. Next handles that. You define pages and layouts.

3. Data fetching

  • CRA: All data fetching happens on the client (e.g. useEffect).
  • Next.js: You can fetch data on the server (in page.tsx, layout.tsx, or server actions) or the client.

This is a major shift, and a big reason performance and SEO improve.

Step 3: Move Shared Code First

Start with pieces that don’t depend on routing or data fetching behavior.

Move these from src/ in CRA to app/ or a top-level src/ in Next.js:

  • UI components (buttons, forms, modals)
  • Hooks (useAuth, useTheme, etc.)
  • Utility functions (formatters, API clients)
  • Styles (CSS modules, Tailwind config, global styles)

Keep import paths consistent where possible. If you used absolute imports in CRA, set them up in jsconfig.json or tsconfig.json in Next.js.

Example tsconfig.json paths:

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/components/*": ["./components/*"],
      "@/lib/*": ["./lib/*"]
    }
  }
}

Step 4: Port Your Routes to Next.js Pages

Now, migrate your actual views.

Map CRA routes to Next.js structure

If your CRA App.tsx looks like this:

<Routes>
  <Route path="/" element={<Home />} />
  <Route path="/about" element={<About />} />
  <Route path="/products/:id" element={<ProductDetail />} />
</Routes>

In Next.js App Router, you might create:

app/
  page.tsx                 -> Home
  about/
    page.tsx               -> About
  products/
    [id]/
      page.tsx             -> ProductDetail

Copy each page component from CRA into the appropriate page.tsx. Adjust imports as necessary.

Use layouts for shared UI

If your CRA App.tsx wraps all pages in a layout (navbar, footer, etc.), move that to app/layout.tsx.

// app/layout.tsx
import "./globals.css";
import { ReactNode } from "react";

export default function RootLayout({ children }: { children: ReactNode }) {
  return (
    <html lang="en">
      <body>
        <Header />
        <main>{children}</main>
        <Footer />
      </body>
    </html>
  );
}

This reduces repetition and centralizes app‑wide concerns.

Step 5: Gradually Introduce Server-Side Rendering and SSG

Initially, you can keep using client-side data fetching to minimize behavior changes. Mark pages or components that use hooks like useState or useEffect with the "use client" directive at the top if you’re in the App Router.

"use client";

export default function DashboardPage() {
  // client-side hooks and effects here
}

Once things are stable, start moving data fetching to the server where it makes sense.

Example: Converting a data-heavy page to server rendering

CRA version:

function BlogPost() {
  const { slug } = useParams();
  const [post, setPost] = useState<Post | null>(null);

  useEffect(() => {
    fetch(`/api/posts/${slug}`)
      .then(res => res.json())
      .then(setPost);
  }, [slug]);

  // render
}

Next.js (App Router) server-rendered page:

// app/blog/[slug]/page.tsx

async function getPost(slug: string) {
  const res = await fetch(`${process.env.API_URL}/posts/${slug}`, {
    cache: "no-store",
  });
  if (!res.ok) throw new Error("Failed to fetch post");
  return res.json();
}

export default async function BlogPostPage({
  params,
}: {
  params: { slug: string };
}) {
  const post = await getPost(params.slug);

  return (
    <article>
      <h1>{post.title}</h1>
      <div dangerouslySetInnerHTML={{ __html: post.content }} />
    </article>
  );
}

Now the HTML for the blog post is generated on the server, improving SEO and initial load performance.

Step 6: Use Next.js for Backend Logic (API Routes & Server Actions)

Next.js isn’t only about rendering; it’s a full-stack platform.

If you previously had:

  • A separate Node/Express server
  • Or an ad-hoc API inside your CRA project

You can often move endpoints into Next.js API routes or server actions.

Example API route:

// app/api/posts/[id]/route.ts
import { NextResponse } from "next/server";

export async function GET(_: Request, { params }: { params: { id: string } }) {
  const post = await db.posts.find(params.id);
  return NextResponse.json(post);
}

This keeps your frontend and backend logic in one cohesive codebase.

Step 7: Harden for Production

A production-ready Next.js app requires more than just working code.

Environment variables

Use .env.local, .env.production, etc., and reference with process.env.MY_KEY. Configure these in your hosting platform (e.g. Vercel, AWS, Netlify).

Build & deployment

  • Add a CI pipeline (npm run lint, npm run test, npm run build).
  • Ensure your hosting supports Next.js features you use (SSR, edge functions, etc.).
  • Monitor bundle sizes and performance (next build output, Lighthouse).

Observability

  • Add logging and error tracking (e.g. Sentry, LogRocket).
  • Use Next’s built‑in analytics or your own tooling.

This is where real‑world migrations prove their value: teams often report simpler deploy pipelines and more predictable performance once on Next.js.

Common Pitfalls and How to Avoid Them

  • Mixing client and server concepts: When using the App Router, clearly separate server components (default) from client components ("use client").
  • Overusing client components: Only mark components as client when they need hooks, browser APIs, or event handlers; let everything else stay server‑rendered for better performance.
  • Ignoring SEO and metadata: Use Next’s metadata API or <Head> equivalents to define titles, descriptions, and Open Graph data per page.
  • Big-bang rewrites: Migrate incrementally. Ship small pieces, validate, then move on.

Conclusion: Your First Migration Is Just the Beginning

Migrating from Create React App to Next.js is no longer a risky experiment; it’s a proven modernization path that aligns your app with how React is built and deployed in 2025.

By following a structured, incremental approach:

  1. Bootstrap a Next.js app
  2. Move shared components and utilities
  3. Port routes into file-based pages
  4. Gradually adopt server-side rendering and static generation
  5. Consolidate backend logic with API routes and server features
  6. Harden your setup for real production traffic

You’ll end up not just with “a React app that works,” but with a production-ready full-stack platform: faster, more scalable, and far better optimized for SEO and modern user expectations.

Your first migration will teach you the patterns. After that, Next.js becomes not just a tool you use—but the default way you think about building React applications for the web.

From React App to Production-Ready Next.js: A Practical Guide to Your First Migration | Rain Lag