1---
2name: vite-rolldown
3description: Vite 8 Rolldown bundler and Oxc transformer migration
4---
5 
6# Rolldown Migration (Vite 8)
7 
8Vite 8 replaces esbuild+Rollup with Rolldown, a unified Rust-based bundler.
9 
10## What Changed
11 
12| Before (Vite 7) | After (Vite 8) |
13|-----------------|----------------|
14| esbuild (dev transform) | Oxc Transformer |
15| esbuild (dep pre-bundling) | Rolldown |
16| Rollup (production build) | Rolldown |
17| `rollupOptions` | `rolldownOptions` |
18| `esbuild` option | `oxc` option |
19 
20## Performance Impact
21 
22- 10-30x faster than Rollup for production builds
23- Matches esbuild's dev performance
24- Unified behavior between dev and build
25 
26## Config Migration
27 
28### rollupOptions → rolldownOptions
29 
30```ts
31// Before (Vite 7)
32export default defineConfig({
33  build: {
34    rollupOptions: {
35      external: ['vue'],
36      output: { globals: { vue: 'Vue' } },
37    },
38  },
39})
40 
41// After (Vite 8)
42export default defineConfig({
43  build: {
44    rolldownOptions: {
45      external: ['vue'],
46      output: { globals: { vue: 'Vue' } },
47    },
48  },
49})
50```
51 
52### esbuild → oxc
53 
54```ts
55// Before (Vite 7)
56export default defineConfig({
57  esbuild: {
58    jsxFactory: 'h',
59    jsxFragment: 'Fragment',
60  },
61})
62 
63// After (Vite 8)
64export default defineConfig({
65  oxc: {
66    jsx: {
67      runtime: 'classic',
68      pragma: 'h',
69      pragmaFrag: 'Fragment',
70    },
71  },
72})
73```
74 
75### JSX Configuration
76 
77```ts
78export default defineConfig({
79  oxc: {
80    jsx: {
81      runtime: 'automatic',  // or 'classic'
82      importSource: 'react', // for automatic runtime
83    },
84    jsxInject: `import React from 'react'`,  // auto-inject
85  },
86})
87```
88 
89### Custom Transform Targets
90 
91```ts
92export default defineConfig({
93  oxc: {
94    include: ['**/*.ts', '**/*.tsx'],
95    exclude: ['node_modules/**'],
96  },
97})
98```
99 
100## Plugin Compatibility
101 
102Most Vite plugins work unchanged. Rolldown supports Rollup's plugin API.
103 
104If a plugin only works during build:
105 
106```ts
107{
108  ...rollupPlugin(),
109  enforce: 'post',
110  apply: 'build',
111}
112```
113 
114## New Capabilities
115 
116Rolldown unlocks features not possible before:
117 
118- Full bundle mode (experimental)
119- Module-level persistent cache
120- More flexible chunk splitting
121- Module Federation support
122 
123## Gradual Migration
124 
125For large projects, migrate via `rolldown-vite` first:
126 
127```bash
128# Step 1: Test with rolldown-vite
129pnpm add -D rolldown-vite
130 
131# Replace vite import in config
132import { defineConfig } from 'rolldown-vite'
133 
134# Step 2: Once stable, upgrade to Vite 8
135pnpm add -D vite@8
136```
137 
138## Overriding Vite in Frameworks
139 
140When framework depends on older Vite:
141 
142```json
143{
144  "pnpm": {
145    "overrides": {
146      "vite": "8.0.0"
147    }
148  }
149}
150```
151 
152<!--
153Source references:
154- https://vite.dev/blog/announcing-vite8-beta
155- https://vite.dev/blog/announcing-vite7
156- https://vite.dev/config/shared-options#oxc
157-->
158