bun

| Topic | Reference |

| ----------------- | ------------------------------------ |

| Package Manager | references/package-manager.md |

| Project Setup | references/project-scaffolding.md |

| Development | references/development.md |

| Module System | references/module-system.md |

| TypeScript & JSX | references/typescript-jsx.md |

| Configuration | references/bunfig.md |

| HTTP Server | references/http-server.md |

| WebSockets | references/websockets.md |

| File I/O | references/file-io.md |

| SQLite | references/sqlite.md |

| S3 Storage | references/s3.md |

| Redis | references/redis.md |

| Low-Level Network | references/networking-low-level.md |

| Fetch API | references/fetch.md |

| Shell Scripts | references/shell.md |

| Spawn Process | references/spawn.md |

| Workers | references/workers.md |

| Native FFI | references/native-interop.md |

| C/C++ Compile | references/cc.md |

| Transpiler | references/transpiler.md |

| Plugins | references/plugins.md |

| FS Router | references/file-system-router.md |

| Environment Vars | references/env.md |

| Utilities | references/utilities.md |

| Node.js Compat | references/nodejs-compat.md |

• Running TypeScript/JSX without build step
• Fast HTTP server with native routing
• SQLite database (embedded, no deps)
• WebSocket server/client
• S3-compatible storage (AWS, R2, MinIO)
• Redis caching/pub-sub
• Cross-platform shell scripts
• Markdown parsing (v1.3.8+)
• Native library calls via FFI

• 4x faster startup than Node.js
• Native TypeScript/JSX — no tsconfig needed
• ESM + CommonJS — both work seamlessly
• Web APIs built-in — fetch, WebSocket, etc.
• 30x faster installs than npm

```bash

# Run TypeScript directly

bun run index.ts

# Install packages

bun install

# Run package.json script

bun run dev

# Execute package binary

bunx cowsay "Hello"

# Run tests

bun test

# Build for production

bun build ./index.ts --outdir ./dist

# Bundle analysis for LLMs (v1.3.8+)

bun build ./index.ts --metafile-md --outdir ./dist

```

| Don't | Do |

| ---------------------- | ------------------------ |

| http.createServer() | Bun.serve() |

| fs.readFileSync() | Bun.file().text() |

| better-sqlite3 | bun:sqlite |

| child_process.exec() | Bun.$ or Bun.spawn() |

| dotenv | Built-in .env support |

HTTP Server

```ts

Bun.serve({

port: 3000,

fetch(req) {

const url = new URL(req.url);

if (url.pathname === "/api/data") {

return Response.json({ ok: true });

}

return new Response("Not Found", { status: 404 });

},

});

```

File Operations

```ts

// Read

const content = await Bun.file("data.txt").text();

// Write

await Bun.write("output.txt", "Hello World");

// JSON

const config = await Bun.file("config.json").json();

```

SQLite

```ts

import { Database } from "bun:sqlite";

const db = new Database("app.db");

db.run("CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT)");

const insert = db.prepare("INSERT INTO users (name) VALUES (?)");

insert.run("Alice");

const users = db.query("SELECT * FROM users").all();

```

WebSocket Server

```ts

Bun.serve({

fetch(req, server) {

if (server.upgrade(req)) return;

return new Response("Upgrade failed", { status: 400 });

},

websocket: {

message(ws, message) {

ws.send(Echo: ${message});

},

},

});

```

Shell Commands

```ts

import { $ } from "bun";

// Simple command

const files = await $ls -la.text();

// With variables (auto-escaped)

const name = "my file.txt";

await $cat ${name};

// Piping

await $cat data.csv | grep "pattern" | wc -l;

```

S3 Storage

```ts

import { s3 } from "bun";

// Upload

await s3.file("uploads/doc.pdf").write(data);

// Download

const content = await s3.file("uploads/doc.pdf").text();

// Presigned URL

const url = s3.presign("uploads/doc.pdf", { expiresIn: 3600 });

```

Redis

```ts

import { redis } from "bun";

await redis.set("key", "value");

const value = await redis.get("key");

await redis.expire("key", 3600);

```

Testing

```ts

import { expect, test, describe } from "bun:test";

describe("math", () => {

test("2 + 2 = 4", () => {

expect(2 + 2).toBe(4);

});

});

```

```toml

[run]

watch = true

[install]

registry = "https://registry.npmjs.org"

[test]

coverage = true

```

```bash

# .env files loaded automatically

DATABASE_URL=postgres://localhost/mydb

```

```ts

// Access

Bun.env.DATABASE_URL

process.env.DATABASE_URL

import.meta.env.DATABASE_URL

```

• [Documentation](https://bun.sh/docs)
• [GitHub](https://github.com/oven-sh/bun)
• [Discord](https://bun.sh/discord)