Next.js introduced the app/ directory (beta). This is the result of the Layouts RFC previously published for community feedback. This includes support for:

• Layouts: Easily share UI while preserving state and avoiding re-renders.
• Server Components: Making server-first the default for the most dynamic applications.
• Streaming: Display instant loading states and stream in updates.
• Suspense for Data Fetching: async/await support and the use hook for component-level fetching.

The app/ directory can coexist with the existing pages directory for incremental adoption. While you don't need to use the app/ directory when upgrading to Next.js 13, we're laying the foundations to build complex interfaces while shipping less JavaScript.

1. Install dependencies: yarn
2. Start the dev server: yarn dev

https://beta.nextjs.org/docs

vercel/next.js#41745