Migrating 8 SvelteKit Sites to Vite 8 in a day: What We Learned

Vite 8 dropped on March 12, 2026. Two days later, we'd migrated 8 SvelteKit projects — a mix of monorepos and standalone sites, all deployed to Cloudflare Workers. The migration was mostly mechanical, and the builds got faster. Let me share a couple lessons learned. What Vite 8 Changes Vite 8 replaces a kind of "split-brain" bundler architecture. Vite 7 used esbuild for development transforms and dependency optimization, then switched to Rollup for production builds. Two different tools doing overlapping jobs, with subtly different behavior in each environment. Vite 8 unifies to use only Rolldown, a Rust-based bundler. Oxc handles JavaScript transforms and minification (replacing esbuild's role), and Lightning CSS takes over CSS minification. One bundler means consistent dev and production. So is Vite 8 any good? Yes! Looking at our Cloudflare UI for each worker, overall build times dropped about 15s in most projects, with a couple dropping ~45-60sec. That's mostly 10-15%, with a coupl