Sapper

Sapper is a framework for building high-performance universal (SSR) web applications with Svelte, similar to Next.js. It provides file-based routing, server-side rendering, code splitting, and offline support via service workers. The current stable version is 0.28.10, but development has shifted to SvelteKit (the successor). Sapper uses Rollup or Webpack for bundling and requires Svelte ^3.17.3 as a peer dependency. It is now in maintenance mode; new projects should use SvelteKit instead.