What is Next.js?
Next.js is a React framework that adds server-side rendering, static site generation, file-based routing, and build tooling on top of React. It lets a single codebase render pages on the server (for fast first paint and SEO) or statically export them ahead of time, which is how this site itself is built.
Example
A file at app/tools/[slug]/page.tsx automatically becomes the route /tools/:slug.
Related tool
Try it on ToolSphere — runs entirely in your browser, nothing is uploaded to a server.