bun-runtime

Name: bun-runtime
Author: affaan-m

Use Bun for runtime, bundling, testing, packages, and Node migration decisions.

Stars

★ 229,796

Source

GitHub

Updated

2026-07-15

// securityLow risk

Prompt only, no code
Open source
Community-trusted· 229.8k

Running security audit…

Credentials
Network egress
Code execution
Data access
Supply chain

// install

Copy the install command and let the AI configure it · recommended for beginners

Please install the "bun-runtime" skill from askskill:
1. Download https://raw.githubusercontent.com/affaan-m/ECC/main/skills/bun-runtime/SKILL.md
2. Save it as ~/.claude/skills/bun-runtime/SKILL.md
3. Reload skills and tell me it's ready

// download

Download SKILL.mdInstall manifest ↗

// examples

Evaluate whether to switch to Bun

Prompt

I have a Node.js web project and want to evaluate whether it should move to Bun. Compare startup speed, dependency compatibility, testing, bundling, and Vercel deployment support, then give clear criteria for when migration makes sense and when it does not.

Expected

A Bun vs Node comparison with a migration recommendation and decision checklist.

Create a Bun migration guide

Prompt

Help migrate an existing Node.js project to Bun. Provide a step-by-step guide covering package.json script changes, dependency install commands, test execution, common compatibility troubleshooting, and a rollback plan.

Expected

An actionable migration plan with command examples, risk notes, and rollback guidance.

Set up a development workflow with Bun

Prompt

Design a Bun-based development workflow for a TypeScript backend project, including runtime, package management, bundling, test commands, and recommended project structure and CI practices for team collaboration.

Expected

A complete Bun workflow plan with commands, structure recommendations, and CI setup ideas.

// docs

Bun Runtime

Bun is a fast all-in-one JavaScript runtime and toolkit: runtime, package manager, bundler, and test runner.

When to Use

Prefer Bun for: new JS/TS projects, scripts where install/run speed matters, Vercel deployments with Bun runtime, and when you want a single toolchain (run + install + test + build).
Prefer Node for: maximum ecosystem compatibility, legacy tooling that assumes Node, or when a dependency has known Bun issues.

Use when: adopting Bun, migrating from Node, writing or debugging Bun scripts/tests, or configuring Bun on Vercel or other platforms.

How It Works

Runtime: Drop-in Node-compatible runtime (built on JavaScriptCore, implemented in Zig).
Package manager: bun install is significantly faster than npm/yarn. Lockfile is bun.lock (text) by default in current Bun; older versions used bun.lockb (binary).
Bundler: Built-in bundler and transpiler for apps and libraries.
Test runner: Built-in bun test with Jest-like API.

Migration from Node: Replace node script.js with bun run script.js or bun script.js. Run bun install in place of npm install; most packages work. Use bun run for npm scripts; bun x for npx-style one-off runs. Node built-ins are supported; prefer Bun APIs where they exist for better performance.

Vercel: Set runtime to Bun in project settings. Build: bun run build or bun build ./src/index.ts --outdir=dist. Install: bun install --frozen-lockfile for reproducible deploys.

Examples

Run and install

# Install dependencies (creates/updates bun.lock or bun.lockb)
bun install

# Run a script or file
bun run dev
bun run src/index.ts
bun src/index.ts

Scripts and env

bun run --env-file=.env dev
FOO=bar bun run script.ts

Testing

bun test
bun test --watch

// test/example.test.ts
import { expect, test } from "bun:test";

test("add", () => {
  expect(1 + 2).toBe(3);
});

Runtime API

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

Bun.serve({
  port: 3000,
  fetch(req) {
    return new Response("Hello");
  },
});