Vite

Vite 7

Build tooling and dev server for React projects. Vite 7 (June 2025) is ESM-only, requires Node.js 20.19+ / 22.12+, and defaults browser target to baseline-widely-available. The user's stack uses rolldown-vite (Rust-based drop-in replacement), @vitejs/plugin-react, @tailwindcss/vite, @tanstack/router-plugin, @cloudflare/vite-plugin, and @tanstack/react-start.

Critical Rules

Plugin Order Matters

TanStack Start or TanStack Router plugin MUST come before @vitejs/plugin-react:

plugins: [
  tanstackStart(),      // or tanstackRouter() for SPA
  tailwindcss(),
  react(),              // ALWAYS last among framework plugins
]

Wrong order causes route generation failures and HMR breakage.

Vite 7 is ESM-Only

Vite 7 distributes as ESM only. Your vite.config.ts must use import/export syntax. CJS require() is not supported in config files. Node.js 20.19+ supports require(esm) natively, so Vite can still be required by CJS consumers.

No tailwind.config.js

Tailwind CSS v4 uses CSS-first configuration. Never create tailwind.config.js/tailwind.config.ts. Use @tailwindcss/vite plugin and configure in CSS via @theme, @utility, @plugin.

Environment Variables Need VITE_ Prefix

Only variables prefixed with VITE_ are exposed to client code via import.meta.env. Server-only secrets must NOT use this prefix. For type safety, augment ImportMetaEnv in vite-env.d.ts.

splitVendorChunkPlugin Is Removed

Removed in Vite 7. Use build.rollupOptions.output.manualChunks for custom chunk splitting.

Configuration

vite.config.ts (Full Stack with TanStack Start)

import { defineConfig } from 'vite'
import { tanstackStart } from '@tanstack/react-start/plugin/vite'
import { cloudflare } from '@cloudflare/vite-plugin'
import tailwindcss from '@tailwindcss/vite'
import react from '@vitejs/plugin-react'

export default defineConfig({
  plugins: [
    tanstackStart(),
    cloudflare(),
    tailwindcss(),
    react(),
  ],
  resolve: {
    alias: {
      '@': new URL('./src', import.meta.url).pathname,
    },
  },
})

vite.config.ts (SPA with TanStack Router)

import { defineConfig } from 'vite'
import { tanstackRouter } from '@tanstack/router-plugin/vite'
import tailwindcss from '@tailwindcss/vite'
import react from '@vitejs/plugin-react'

export default defineConfig({
  plugins: [
    tanstackRouter({ autoCodeSplitting: true }),
    tailwindcss(),
    react(),
  ],
  resolve: {
    alias: {
      '@': new URL('./src', import.meta.url).pathname,
    },
  },
})

React Compiler

react({
  babel: {
    plugins: [['babel-plugin-react-compiler', {}]],
  },
})

Install: pnpm add -D babel-plugin-react-compiler. Auto-memoizes components and hooks - no manual useMemo/useCallback.

Path Aliases

Use import.meta.url for ESM-compatible resolution (no __dirname in ESM):

resolve: {
  alias: {
    '@': new URL('./src', import.meta.url).pathname,
  },
}

Mirror in tsconfig.json: "paths": { "@/*": ["./src/*"] }

Environment Variables

Files: .env, .env.local, .env.[mode], .env.[mode].local. Only VITE_-prefixed vars exposed to client. Built-in constants: import.meta.env.MODE, .DEV, .PROD, .SSR, .BASE_URL.

Type augmentation in src/vite-env.d.ts:

interface ImportMetaEnv {
  readonly VITE_API_URL: string
}
interface ImportMeta {
  readonly env: ImportMetaEnv
}

Plugin Ecosystem

@vitejs/plugin-react

Provides Fast Refresh (HMR for React), JSX transform, and optional Babel plugin pipeline. Always place last among framework plugins.

import react from '@vitejs/plugin-react'

react()                          // zero-config default
react({ fastRefresh: false })    // disable for debugging HMR issues

@tailwindcss/vite

Native Vite integration for Tailwind CSS v4. Replaces PostCSS-based setup - no postcss.config.js needed.

import tailwindcss from '@tailwindcss/vite'

tailwindcss()  // zero-config, reads @theme from CSS

@tanstack/router-plugin/vite

File-based route generation for TanStack Router. Must come before react().

import { tanstackRouter } from '@tanstack/router-plugin/vite'

tanstackRouter({ autoCodeSplitting: true })

@tanstack/react-start/plugin/vite

Full-stack plugin for TanStack Start. Includes router plugin internally - do NOT add both.

import { tanstackStart } from '@tanstack/react-start/plugin/vite'

tanstackStart()                           // default SSR
tanstackStart({ spa: { enabled: true } }) // SPA mode (no SSR)

@cloudflare/vite-plugin

Runs Worker code inside workerd during dev, matching production behavior. Uses Vite's Environment API for runtime integration.

import { cloudflare } from '@cloudflare/vite-plugin'

cloudflare()  // reads wrangler.jsonc by default

// Programmatic config (no wrangler file needed)
cloudflare({
  config: {
    name: 'my-worker',
    compatibility_flags: ['nodejs_compat'],
  },
})

Dev Server

Proxy Configuration

server: {
  proxy: {
    '/api': {
      target: 'http://localhost:8787',
      changeOrigin: true,
      rewrite: (path) => path.replace(/^\/api/, ''),
    },
    '/ws': { target: 'ws://localhost:8787', ws: true },
  },
}

HMR Troubleshooting

Behind a reverse proxy:

server: {
  hmr: { protocol: 'ws', host: 'localhost', port: 5173, clientPort: 443 },
}

File Warmup

server: {
  warmup: {
    clientFiles: ['./src/components/*.tsx', './src/routes/__root.tsx'],
  },
}

Build Optimization

Default Browser Target

Vite 7 targets baseline-widely-available (Chrome 107+, Edge 107+, Firefox 104+, Safari 16+). Override: build.target: 'es2020' or ['chrome90', 'safari14'].

Manual Chunks

build: {
  rollupOptions: {
    output: {
      manualChunks: {
        'react-vendor': ['react', 'react-dom'],
        'tanstack': ['@tanstack/react-router', '@tanstack/react-query'],
      },
    },
  },
}

Dynamic splitting by function:

manualChunks(id) {
  if (id.includes('node_modules')) {
    if (id.includes('react')) return 'react-vendor'
    if (id.includes('@tanstack')) return 'tanstack'
    return 'vendor'
  }
}

Bundle Analysis

pnpm add -D rollup-plugin-visualizer

import { visualizer } from 'rollup-plugin-visualizer'

// Add to plugins array
visualizer({ filename: 'stats.html', open: true, gzipSize: true })

See build-optimization.md for detailed chunking strategies, CSS splitting, asset inlining, source maps, and performance tuning.

Rolldown Integration

What is rolldown-vite

rolldown-vite is a Rust-based drop-in replacement for Vite's bundler, developed by the Vite team (sponsored by VoidZero). It replaces both esbuild and Rollup with a single high-performance tool built on Rolldown and the Oxc toolkit. Build time reductions of 3x to 16x have been reported, with memory usage cut by up to 100x on large projects.

Rolldown will become the default bundler in Vite 8 (currently in beta). Using rolldown-vite today prepares your project for the transition.

Note: Vite 7 requires Vitest 3.2+ for compatibility. Earlier Vitest versions will not work.

Installation

In package.json, alias vite to rolldown-vite:

{
  "devDependencies": {
    "vite": "npm:rolldown-vite@latest"
  }
}

For monorepos or frameworks with Vite as a peer dependency, use overrides:

{
  "pnpm": {
    "overrides": {
      "vite": "npm:rolldown-vite@latest"
    }
  }
}

Then run pnpm install. No config changes needed - it is a drop-in replacement.

Key Differences from Standard Vite

• No esbuild dependency - Oxc handles all transforms and minification (config still shows minify: 'esbuild' but the underlying engine is Oxc)
• Faster builds - Rust-native bundling, especially for large projects
• Same plugin API - Rollup/Vite plugins work without changes in most cases
• Patch versions may break - rolldown-vite follows Vite major/minor but patches are independent

Compatibility Notes

Most frameworks and Vite plugins work out of the box. Check the rolldown-vite repo for known issues and changelog. Some warnings about unsupported options may appear during the transition period.

Environment API

Experimental API introduced in Vite 6, improved in Vite 7 with the buildApp hook. Enables multi-target builds (browser, Node.js, edge runtimes) from a single Vite config.

How It Works

Each environment has its own module graph, plugin pipeline, and build config. The @cloudflare/vite-plugin uses this to run Worker code inside workerd during dev, matching production behavior.

buildApp Hook (Vite 7)

Frameworks coordinate building multiple environments. Config-level form (most common):

export default defineConfig({
  builder: {
    async buildApp(builder) {
      await builder.build(builder.environments.client)
      await builder.build(builder.environments.server)
    },
  },
})

Plugin hook form (for plugin authors):

{
  name: 'my-framework',
  buildApp: async (builder) => {
    const environments = Object.values(builder.environments)
    return Promise.all(
      environments.map((env) => builder.build(env))
    )
  },
}

Multi-Environment Config

export default defineConfig({
  environments: {
    client: {
      build: { outDir: 'dist/client' },
    },
    server: {
      build: { outDir: 'dist/server' },
    },
  },
})

For most projects, the @cloudflare/vite-plugin or @tanstack/react-start handles environment configuration automatically. Direct Environment API usage is for framework authors.

Deployment

Cloudflare Workers (via TanStack Start)

Add cloudflare() to plugins and create wrangler.jsonc:

// wrangler.jsonc
{
  "name": "my-app",
  "compatibility_date": "2025-01-01",
  "compatibility_flags": ["nodejs_compat"],
  "main": "./dist/server/index.js",
  "assets": { "directory": "./dist/client" }
}

pnpm vite build && pnpm wrangler deploy

Static SPA

Build produces dist/. Deploy to any static host (Cloudflare Pages, Vercel, Netlify).

Prerendering (SSG)

tanstackStart({ prerender: { enabled: true, crawlLinks: true } })

Best Practices

1. Plugin order - framework plugins first, then utilities, then react() last
2. Use rolldown-vite - drop-in replacement with 3-16x faster builds
3. Set staleTime in dev - avoid unnecessary refetches during HMR reloads
4. Warm up critical files - use server.warmup for frequently accessed modules
5. Split vendor chunks - separate react, @tanstack/* into stable chunks for caching
6. Never use transition-all - specific properties only for CSS transitions
7. Use import.meta.url for path resolution in ESM config files
8. Analyze bundles regularly - use rollup-plugin-visualizer before deploys
9. Keep VITE_ prefix discipline - only public values; secrets go in server functions
10. Set build.sourcemap for production - 'hidden' for error tracking without exposing source

Resources

• Vite Docs: https://vite.dev/guide/
• Vite 7 Blog: https://vite.dev/blog/announcing-vite7
• Migration Guide: https://vite.dev/guide/migration
• Build Options: https://vite.dev/config/build-options
• Server Options: https://vite.dev/config/server-options
• Env Variables: https://vite.dev/guide/env-and-mode
• Rolldown-Vite: https://voidzero.dev/posts/announcing-rolldown-vite
• Cloudflare Vite Plugin: https://developers.cloudflare.com/workers/vite-plugin/
• Plugin React: https://github.com/vitejs/vite-plugin-react
• GitHub: https://github.com/vitejs/vite