Deno vs Bun vs Node.js: JavaScript Runtime Comparison 2025

The Runtime Wars

JavaScript has gone from "runs in browsers only" to running servers, CLIs, mobile apps, and even embedded systems. In 2025, developers have three serious runtime choices — and the competition is making all of them better.

Node.js: The Incumbent

Node.js powers most of the JavaScript ecosystem. It is stable, battle-tested, and has the largest package ecosystem in the world.

Version: Node.js 22 LTS (as of late 2024)
Package Manager: npm (or yarn, pnpm)
TypeScript: Via ts-node, tsx, or compile step
Creator: Ryan Dahl (2009), now OpenJS Foundation

# Install (via mise, nvm, or direct)
mise install node@22

# Run TypeScript (using tsx)
npx tsx src/server.ts

# Package management
npm install express zod

# Built-in test runner (Node 20+)
node --test src/**/*.test.ts

Key features in Node.js 22:

• Native fetch API
• Built-in test runner
• Single executable applications
• Permission model (experimental)
• WebSocket client

Bun: The Speed Demon

Bun is written in Zig and uses JavaScriptCore (Safari's engine) instead of V8. It is designed to be the fastest JavaScript runtime.

Version: Bun 1.x
Package Manager: Built-in (bun install)
TypeScript: Native, zero config
Creator: Jarred Sumner (2022), Oven

# Install
curl -fsSL https://bun.sh/install | bash

# Run TypeScript directly
bun run src/server.ts

# Package management (5-10x faster than npm)
bun install express zod

# Built-in test runner
bun test

# Built-in bundler
bun build src/index.ts --outdir=dist

Key features:

• Native TypeScript and JSX support
• Built-in package manager, test runner, and bundler
• SQLite built-in
• S3 client built-in (Bun 1.2+)
• Hot module reloading
• Node.js compatibility layer

Deno: The Secure Choice

Deno was created by Ryan Dahl (Node.js creator) to fix what he saw as Node's design mistakes. It prioritizes security and web standards.

Version: Deno 2.x
Package Manager: Built-in (deno add) or URL imports
TypeScript: Native, zero config
Creator: Ryan Dahl (2018), Deno Land

# Install
curl -fsSL https://deno.land/install.sh | sh

# Run TypeScript directly
deno run src/server.ts

# With permissions
deno run --allow-net --allow-read src/server.ts

# Package management (Deno 2.x supports npm packages)
deno add npm:express npm:zod

# Built-in tools
deno test
deno lint
deno fmt
deno bench

Key features:

• Secure by default (explicit permissions)
• Web Standard APIs (fetch, URL, Streams)
• Built-in linter, formatter, test runner
• npm compatibility (Deno 2.x)
• JSR (JavaScript Registry) support
• Jupyter notebook support

Performance Benchmarks

HTTP Server (requests/sec)

Package Install Time (500 packages)

Startup Time

Bun wins on raw speed. Deno is the middle ground. Node is the slowest but most compatible.

TypeScript Experience

Node.js

// package.json
{
  "scripts": {
    "dev": "tsx watch src/server.ts",
    "build": "tsc",
    "start": "node dist/server.js"
  },
  "devDependencies": {
    "typescript": "^5.5",
    "tsx": "^4.0",
    "@types/node": "^22"
  }
}

Node requires compilation or a loader like tsx. Type checking is a separate step.

Bun

// Just run it. No config needed.
// bun run server.ts
const server = Bun.serve({
  port: 3000,
  fetch(req) {
    return new Response("Hello from Bun!");
  },
});
console.log("Listening on port " + server.port);

Bun runs TypeScript natively. No tsconfig needed (but supported).

Deno

// deno run --allow-net server.ts
Deno.serve({ port: 3000 }, (req) => {
  return new Response("Hello from Deno!");
});

Deno runs TypeScript natively with full type checking.

Ecosystem Compatibility

Security Model

• Node.js: No security sandbox. Full file system and network access.
• Bun: Same as Node. No security sandbox.
• Deno: Secure by default. Must explicitly grant --allow-net, --allow-read, --allow-write, --allow-env.

Deno's permission model is a genuine advantage for running untrusted code or limiting blast radius.

Which Should You Choose?

Choose Node.js if:

• You need maximum ecosystem compatibility
• Your team already knows Node
• You use Next.js or Nest.js
• You need long-term stability and LTS support

Choose Bun if:

• Performance is your top priority
• You want the fastest development experience
• You are starting a new project without legacy dependencies
• You want built-in SQLite, S3, and testing

Choose Deno if:

• Security is important (sandboxed by default)
• You prefer web standards over Node APIs
• You want built-in linting, formatting, and testing
• You are building for edge/serverless deployment

At TechSaaS, we use Node.js 22 for production services (stability), Bun for development tooling (speed), and evaluate Deno for edge deployments. The key insight is that all three are converging — Deno and Bun now support npm packages, and Node is adopting web standards. Choose based on your team and use case, not hype.

Need help choosing a tech stack? Contact [email protected].