File-based routing (Next.js, Remix) maps file system structure to routes: app/about/page.tsx becomes /about. It is convention-over-configuration — less setup, more predictability.
React Router v7 (Remix merger) supports both file-based and configuration routing. It adds loaders, actions, and error boundaries at the route level.
TanStack Router is type-safe with auto-generated route types. It offers search params validation, layout routes, and virtual file routes.
Key concepts: nested layouts, dynamic segments [id], catch-all routes [...slug], parallel routes, route groups (folder name in parentheses).
Layouts wrap child routes without remounting. Loading states with Suspense boundaries provide instant feedback. Error boundaries catch route-level errors gracefully.