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Node.js vs Bun vs Deno: Which JavaScript Runtime in 2026?

Three runtimes run JavaScript outside the browser. How Node.js, Bun and Deno differ on speed, compatibility, TypeScript support, security and built-in tools — and why most apps should still start on Node.js.

To run JavaScript on a server, you need a runtime — the program that executes your code outside a browser. For over a decade that meant Node.js. Now there are two serious alternatives: Bun and Deno. Here's how they compare, and which one a new project should pick.

(What's a runtime? Start with what is Node.js?)

The quick answer

  • Most apps: Node.js. Maximum compatibility, every host supports it, every tutorial assumes it.
  • You want speed and an all-in-one toolkit, and your dependencies work on it: Bun.
  • You want security restrictions by default and built-in tooling, and like its approach: Deno.

Node.js

Released in 2009, built on Chrome's V8 JavaScript engine. It's what nearly every JavaScript backend, build tool and framework was built for.

  • Compatibility: total. Every npm package works.
  • TypeScript: current versions can run .ts files directly by stripping the type annotations, though most projects still use a build step or a tool like tsx.
  • Releases: a new major version every six months; even-numbered versions become LTS (long-term support). Use the current LTS for production.
  • Built-ins: a test runner, fetch, a watch mode — more than people realise.

Bun

A newer runtime focused on speed, built on Safari's JavaScriptCore engine and written in the Zig language. Anthropic acquired Bun in December 2025, and it continues as an open-source project.

  • All-in-one: a runtime, package manager, bundler and test runner in one binary.
  • Speed: fast startup, very fast installs, quick test runs.
  • TypeScript: runs .ts and .tsx files directly.
  • Compatibility: aims to be a drop-in replacement for Node.js and runs most npm packages. Occasionally a package relying on an obscure Node.js behaviour misbehaves — test before switching a production app.

Deno

Created by Ryan Dahl, who also created Node.js, to fix what he saw as Node's design mistakes.

  • Secure by default: a script can't read files, access the network or read environment variables unless you grant permission (--allow-net, --allow-read). Good for running code you don't fully trust.
  • TypeScript: first-class, no setup.
  • Built-in tools: formatter, linter, test runner, and more.
  • Compatibility: since Deno 2, it supports npm packages and package.json, so most Node.js code runs. Deno also has its own hosting platform.

Side by side

Node.js Bun Deno
First released 2009 2022 (1.0 in 2023) 2018 (1.0 in 2020)
Engine V8 JavaScriptCore V8
npm compatibility Complete Very high High
Runs TypeScript directly Yes (type stripping) Yes Yes
Permissions by default Full access Full access Restricted
Built-in package manager npm (bundled) Yes Yes
Hosting support Everywhere Growing Growing

Does speed matter for your app?

Benchmarks show Bun winning many raw-speed tests. For a typical web app, the time is mostly spent waiting on the database and network, so switching runtimes rarely changes what users feel. Where Bun's speed does help day to day: installs, test runs and startup time during development.

A sensible approach

  1. Start on Node.js LTS unless you have a reason not to. It's the safest default for hosting, libraries and AI-generated code.
  2. Use Bun as a tool, not necessarily a runtime. bun install and bun test can speed up a Node.js project without changing where it runs in production.
  3. Choose Deno if its permission model or built-in tooling is the specific thing you want.
  4. Pin the version. Whichever you choose, record it ("engines" in package.json, an .nvmrc file, or your Dockerfile) so development and production match. Version drift is a classic works-locally-but-not-in-production cause.

The summary

  • Node.js: the default, with total compatibility and support everywhere.
  • Bun: fast, all-in-one, highly Node-compatible; owned by Anthropic since December 2025.
  • Deno: secure by default with built-in tools, npm-compatible since version 2.
  • Start on Node.js LTS; adopt Bun or Deno for specific benefits, after testing.

EasySpawn servers come with Node.js and Bun ready, alongside Python and other stacks, so you can run whichever runtime your app needs — and Claude Code can test it there before you deploy. See how it works or join the waitlist.

Related: What Is Node.js? · npm vs pnpm vs Yarn vs Bun · Writing a Production Dockerfile for Node.js · Python vs JavaScript

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