/vite-v8

Vite 8 Build, SSR, and Migration Reference

Vite 8 unifies more of the dev/build/runtime story around Rolldown and environment-aware execution.

Rolldown and Oxc Migration

The main migration points are:

• build.rollupOptions → build.rolldownOptions
• esbuild → oxc
• legacy HMR/plugin assumptions → environment-aware hooks and filters

Also watch for older config snippets that still talk about esbuild CSS minification or Rollup-specific extension points as the preferred path. In Vite 8, those examples are often historically accurate but strategically wrong.

SSR Guidance

SSR issues in Vite 8 are often runtime-boundary issues rather than plain bundling issues. Review:

• environments
• this.environment
• ssr.noExternal
• Module Runner concepts

Module Runner

Modern Vite SSR/runtime execution is better explained through Module Runner mental models than older ssrLoadModule-centric guidance.

When SSR debugging feels like “the bundle built but runtime is wrong,” it is often a Module Runner or environment-boundary problem rather than a bundling one.

CSS and Build Output

Lightning CSS is the modern default direction, and build behavior should be validated under the same Vite 8 assumptions used in dev.

Rollup Hook Caveat

Some Rollup hooks behave differently under Rolldown-era execution, especially assumptions about parallelism or dev-only parsing behavior. Do not assume every historical Rollup performance trick still maps 1:1.

Production Checklist

• Run vite build
• Run vite build --ssr <entry> when SSR applies
• Run vite preview
• Validate runtime-specific behavior after externalization decisions