# Node.js vs Bun

URL: https://softwaredictionary.org/compare/nodejs-vs-bun
Last updated: 2026-10-06

In short: Node.js is the long-standing JavaScript runtime built on V8; Bun is a faster-starting runtime on JavaScriptCore that also installs, tests and bundles code.

## What is the difference between Node.js and Bun?

Node.js and Bun both run JavaScript and TypeScript outside the browser, on servers and developer machines. Node.js, released in 2009, is built on Chrome's V8 engine, ships with npm and is the runtime most packages, frameworks and hosts are built for. Bun, started by Jarred Sumner and stable since version 1.0 in 2023, uses JavaScriptCore, the engine behind Safari, is written in Zig and comes as a single `bun` executable that is also a package manager, test runner and bundler.

Bun is designed as a drop-in replacement: it implements Node.js built-in modules such as `node:fs` and `node:http`, reads `package.json` and `node_modules` and runs most npm packages unchanged. So the differences are speed and tooling. Bun starts faster, installs dependencies much faster with `bun install`, runs TypeScript and JSX directly, and includes a Jest-compatible test runner and a bundler; a Node.js project usually pairs the runtime with npm, a bundler such as Vite or esbuild and a test framework, although Node.js has added its own test runner and can strip types from many `.ts` files.

They also work together. Many teams adopt Bun piece by piece, using `bun install` or `bun test` in a Node.js project while production stays on Node.js, and try `bun run` once the tests pass. Bun's own APIs, such as `Bun.serve` and `bun:sqlite`, cover common jobs without extra packages but tie code to Bun. Node.js is governed by the OpenJS Foundation; Bun has been owned by Anthropic since December 2025 and remains open source under the MIT license.

A common misconception is that switching to Bun makes every app much faster. Its biggest gains are in startup, installs and tests; a typical web app spends much of its time waiting on databases and networks, so measure your own workload. Compatibility is also high but not complete: packages that depend on Node.js internals or native add-ons can behave differently, and Node.js has a far longer record in production.

| Aspect | Node.js | Bun |
| --- | --- | --- |
| Engine and core | V8 (Chrome's engine), core in C++ | JavaScriptCore (Safari's engine), core in Zig |
| Released | 2009 | Version 1.0 in 2023 |
| Package manager | npm, installed alongside Node.js | `bun install`, built in and npm-compatible |
| TypeScript and JSX | Strips types from many `.ts` files; JSX needs a build tool | Runs both directly, with no configuration |
| Testing and bundling | `node --test` built in; bundling needs a separate tool | `bun test` (Jest-compatible) and `bun build` built in |
| Speed | The baseline for startup and installs | Faster startup; much faster installs |
| Compatibility | The reference that npm packages are written for | Implements most Node.js APIs; some packages behave differently |
| Governance | An OpenJS Foundation project | Owned by Anthropic since December 2025; MIT-licensed |

## Choose Node.js when

- You need the widest compatibility with npm packages, native add-ons and hosts.
- A long production record matters more than install or startup speed.
- Your team's npm, bundler and test setup already works well.

## Choose Bun when

- Slow installs and test runs hold up daily work or CI.
- You want TypeScript, testing and bundling from one tool with no configuration.
- You are starting a new server or command-line tool and can check compatibility early.
- Fast startup matters, as in scripts and short-lived processes.

## Frequently asked questions

**Is Bun faster than Node.js?**

It usually starts faster and installs packages much faster. For a running web app the gap is smaller, since much of the time goes to databases and networks, so benchmark your own workload.

**Can I use Bun in an existing Node.js project?**

Often, yes. Start with `bun install` or `bun test` while the app keeps running on Node.js, then try `bun run` once the tests pass, since a few packages may still behave differently.

**Is Bun ready for production?**

Bun has had stable releases since version 1.0 in 2023, and many teams run it in production. Run your test suite on it first, because compatibility with every Node.js API and package is not guaranteed.

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