SvelteKit 3.0 ships: config moves to vite.config.ts, $lib becomes #lib

The Svelte team released SvelteKit 3.0, its first major version since 2022. It requires Node 22.17, TypeScript 6, Svelte 5.56.4 and Vite 8; svelte.config.js is removed and the $lib alias is replaced by #lib via package.json subpath imports.

• Minimums: Node 22.17+, TypeScript 6+, Svelte 5.56.4+, Vite 8.0.12+
• svelte.config.js is gone — all config now lives in vite.config.ts
• $lib alias replaced by #lib with mandatory file extensions
• Env vars declared in src/env.ts and validated with Zod