Next.js 15 brings powerful new features to the table. In this part, we explore the foundation: the App Router, Bun as a package manager, and static export for deployment.

Setting Up with Bun

Bun is a fast JavaScript runtime and package manager that pairs well with Next.js 15. Creating a new project takes a single command:

Bun's install speed is noticeably faster than npm or yarn, and its built-in bundler means fewer dependencies in your toolchain.

The App Router

Next.js 15 uses the App Router by default, replacing the legacy Pages Router. The key difference is that every component is a Server Component unless you explicitly opt in to client-side rendering with "use client".

Server Components unlock several benefits:

• Smaller client bundles — Server-only code never ships to the browser
• Direct data access — Query databases or read files without an API layer
• Streaming — The server can send HTML progressively as components render

Static Export

For sites that don't need a running server (blogs, documentation, landing pages), Next.js supports full static export:

Running bun run build with this configuration generates a out/ directory containing plain HTML, CSS, and JavaScript files. You can deploy this to any static hosting service — GitHub Pages, Netlify, Cloudflare Pages, or an S3 bucket.

What's Next

In Part 2, we'll explore the file-based routing system in depth: dynamic routes, route groups, layouts, and how Next.js turns your folder structure into a fully-featured application.