---
name: bun
description: Use Bun instead of Node.js, npm, pnpm, or vite. Provides command mappings, Bun-specific APIs, and development patterns.
---
# Bun Runtime
Use Bun as the default JavaScript/TypeScript runtime and package manager.
## Command Mappings
| Instead of | Use |
|------------|-----|
| `node file.ts` | `bun file.ts` |
| `ts-node file.ts` | `bun file.ts` |
| `npm install` | `bun install` |
| `npm run script` | `bun run script` |
| `jest` / `vitest` | `bun test` |
| `webpack` / `esbuild` | `bun build` |
Bun automatically loads `.env` files - don't use dotenv.
## Bun-Specific APIs
Prefer these over Node.js equivalents:
| API | Purpose | Don't use |
|-----|---------|-----------|
| `Bun.serve()` | HTTP server with WebSocket, HTTPS, routes | express |
| `bun:sqlite` | SQLite database | better-sqlite3 |
| `Bun.redis` | Redis client | ioredis |
| `Bun.sql` | Postgres client | pg, postgres.js |
| `Bun.file()` | File operations | node:fs readFile/writeFile |
| `Bun.$\`cmd\`` | Shell commands | execa |
| `WebSocket` | WebSocket client (built-in) | ws |
## Testing
Use `bun:test` for tests:
```ts
import { test, expect } from "bun:test";
test("description", () => {
expect(1).toBe(1);
});
```
Run with `bun test`.
## Frontend Development
Use HTML imports with `Bun.serve()` instead of Vite. Supports React, CSS, Tailwind.
**Server:**
```ts
import index from "./index.html"
Bun.serve({
routes: {
"/": index,
"/api/users/:id": {
GET: (req) => Response.json({ id: req.params.id }),
},
},
development: { hmr: true, console: true }
})
```
**HTML file:**
```html
```
Bun's bundler transpiles `.tsx`, `.jsx`, `.js` automatically. CSS is bundled via `` tags.
Run with `bun --hot ./server.ts` for HMR.
## Documentation
For detailed API docs, see `node_modules/bun-types/docs/**.md`.