🚀 React and Next.js in 2025: Best Practices

React and Next.js are more capable than ever. This guide summarizes the latest ideas for building reliable and scalable applications.

📦 Use the App Router and React Server Components

• The App Router is the current standard. Avoid the older pages/ directory unless you are working on a legacy project.
• React Server Components help reduce JavaScript sent to the client and improve performance.
• Prefer async server components for anything that does not need to run in the browser.

⚙️ Write Server Actions

• Perform mutations directly on the server using server actions.
• This method improves security and removes the need for extra API routes.
• It also allows native form support and better control over requests.

🧱 Group Code by Feature

• Keep components, styles, tests, and data-fetching logic in one folder.
• Organizing by feature helps with readability and long-term maintenance.

🌍 Work with Structured APIs

• Use typed SDKs or GraphQL clients when talking to external services.
• Combine this with headless CMS tools like Strapi to get type safety from OpenAPI or GraphQL schemas.

📐 Validate with TypeScript and Zod

• TypeScript should be used across the project.
• Use Zod or Valibot to validate input and output data, especially when working with forms and server actions.

🔐 Plan Authentication Properly

• Use packages like auth.js or next-auth to manage sign-in and session flows.
• Put authentication checks in middleware or edge functions to handle things early in the request.

⚡ Focus on Speed and Efficiency

• Use streaming, edge rendering, and partial hydration to make the site faster.
• Add the use client directive only in files that run interactive code.

🧪 Keep Testing Practical

• Use Vitest or Jest for unit tests, and Playwright or Cypress for end-to-end flows.
• Focus tests on logic that is complex or easy to break. Avoid testing just to reach 100% coverage.

🧠 Improve the Developer Experience

• Set up tools like Tailwind Typography, ESLint, and Prettier from the beginning.
• If your app grows or your team expands, consider monorepos with tools like Turborepo.

React and Next.js now give you full control over both the backend and frontend. These practices will help you build modern apps that are easy to scale and maintain.