Next.js

The React framework: server rendering, ISR and server components spanning marketing site and app in one codebase.

Next.js is the React framework from Vercel: file-system routing, server-side rendering, static generation, incremental regeneration, API routes and image optimization, all preconfigured. It took React from library to full product framework and normalized the hybrid rendering model the rest of the industry adopted.

Why founders use it: one codebase spans the marketing site and the application. SEO-critical pages render on the server, app screens hydrate into a full SPA, and ISR refreshes content without redeploying. The App Router with server components moved data fetching server-side, which cuts client bundles and simplifies state. Hosting on Vercel is zero-config, and self-hosting via containers is documented.

A realistic setup: marketing pages statically generated, product pages server-rendered with session auth, server actions for mutations, and caching tuned per route. The framework's conventions carry the architecture, so a small team inherits best practices instead of inventing them.

Trade-offs: the framework's pace of change breaks tutorials and plugins, the caching model has real complexity, and the Vercel-shaped defaults want adjusting for other hosts. Compare with Remix for web-standards foundations and Astro when the product is content-first.