Bun vs Deno vs Node

⚔️ Bun vs Deno vs Node — The JavaScript Runtime Showdown

JavaScript runtimes are evolving rapidly, and today’s developers have more options than ever before. Node.js has been the long-standing champion, but Bun and Deno are rising challengers. This blog dives deep into comparing Bun vs Deno vs Node — examining performance, ecosystem, DX, and real-world usage 🔍.

🚀 Overview of the Contenders

• Node.js – The veteran runtime backed by a huge ecosystem and enterprise adoption.
• Deno – Created by Node’s original creator, aiming to fix its shortcomings, with native TypeScript and secure defaults.
• Bun – A speed demon written in Zig, combining runtime, bundler, transpiler, and package manager into one.

📦 Installation & Package Managers

Node.js uses npm or yarn, and has massive registry support. To install:

npm install express

Deno doesn’t use package.json. It imports modules via URLs:

import { serve } from "https://deno.land/std/http/server.ts";

Bun comes with bun install, which is fast and supports npm modules out of the box:

bun add axios

⚙️ Performance Comparison

Benchmarks vary, but here's the general pattern:

• 🔋 Bun: The fastest for HTTP servers, scripts, and bundling.
• 💼 Node: Decent performance, but slower due to legacy baggage.
• 🦕 Deno: Faster than Node, but not as fast as Bun in raw benchmarks.

Example Bun HTTP server:

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

🛡️ Security Models

Node has no sandboxing — scripts run with full access to disk and network.

Deno has secure-by-default permissions (must explicitly allow --allow-read, etc.).

Bun follows Node’s permissive model — fast, but no built-in sandboxing (yet).

📚 TypeScript & JSX Support

• Node: Requires transpilers like Babel or ts-node.
• Deno: Runs TypeScript natively. No extra setup.
• Bun: TypeScript and JSX work out-of-the-box, no config needed.

🧪 Built-in Tooling

Node.js: Relies on external tools for bundling, testing, and transpiling (Webpack, Jest, etc.).

Deno: Includes a linter, test runner, bundler, and formatter built-in.

Bun: Includes:

• bun test for zero-config testing
• bun build for bundling
• bun install as the package manager

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

test("Math check", () => {
  expect(2 + 2).toBe(4);
});

🔗 Compatibility with Node Modules

• Node.js: 100% compatible with npm.
• Deno: Uses URL imports; limited compatibility via third-party tools.
• Bun: Fully supports most Node.js packages and built-in modules (like fs, path).

📁 File Structure & Project Setup

Node: Familiar structure with package.json, node_modules.

Deno: No node_modules; fetches packages to cache folder.

Bun: Uses package.json but skips node_modules during resolution, making it faster and cleaner.

🧠 Developer Experience (DX)

• Bun: Quick startup, no config needed for common tasks, and hot reload support.
• Deno: Type-safe, modern APIs, great DX but fewer compatible libraries.
• Node: Rich ecosystem, but requires more setup for modern dev experience.

📈 Use Cases & Adoption

• 🌍 Node: Best for enterprise apps and mature ecosystems.
• 🔐 Deno: Great for secure scripts, TypeScript-first apps.
• ⚡ Bun: Ideal for startups, side projects, and developers prioritizing speed & DX.

🎯 Final Thoughts: Which One Should You Choose?

Each runtime has its own strengths:

• Use Node if you're building apps that depend on mature libraries and need stability.
• Choose Deno for projects that prioritize security and modern standards.
• Go with Bun if you're chasing blazing-fast performance, integrated tools, and minimal setup.