Node.js vs Bun vs Deno: The Ultimate JavaScript Runtime Comparison

"Should I stick with Node.js, try the new blazing-fast Bun, or give Deno a shot?"

If you're a JavaScript developer in 2025, you've probably heard this debate everywhere. Three months ago, I was in the same boat – comfortable with Node.js but curious about these newer runtimes that everyone's talking about.

Spoiler alert: I ended up testing all three in production. Here's what I learned, and more importantly, which one you should choose for your next project.

The JavaScript Runtime Landscape in 2025

Let me set the stage. We're not just comparing apples to apples here – each runtime has a different philosophy:

Performance: The Numbers Don't Lie

Let's talk about what everyone wants to know – speed. I ran the same Express-like server on all three runtimes:

Simple HTTP Server Benchmark

// Simple server test - same logic across all runtimes
const server = require('http').createServer((req, res) => {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify({ 
        message: 'Hello World',
        timestamp: Date.now(),
        runtime: process.version || Deno.version || Bun.version
    }));
});

server.listen(3000);

// Benchmark: 10k concurrent requests, 30 seconds
// Tool: wrk -t12 -c400 -d30s http://localhost:3000

Package Management:

This is where things get really interesting. Each runtime has a completely different philosophy:

Node.js: The npm Ecosystem

# Traditional Node.js approach
npm init -y
npm install express cors dotenv
npm install -D nodemon typescript @types/node

# package.json dependency hell
{
    "dependencies": {
        "express": "^4.18.2",
        "cors": "^2.8.5",
        "dotenv": "^16.3.1"
    },
    "devDependencies": {
        "nodemon": "^3.0.1",
        "typescript": "^5.1.6",
        "@types/node": "^20.5.0"
    }
}

Bun: Supercharged Package Management

# Bun - Same packages, way faster
bun init
bun add express cors dotenv
bun add -d nodemon typescript @types/node

# Speed comparison (installing express + 20 dependencies):
# npm:  12.3 seconds
# yarn: 8.7 seconds  
# pnpm: 6.2 seconds
# bun:  1.4 seconds ⚡

Deno: No Package Manager Needed

// Deno - Direct imports, no package.json
import { serve } from "https://deno.land/std@0.200.0/http/server.ts";
import { cors } from "https://deno.land/x/cors@v1.2.2/mod.ts";

// Lock versions with import map (deno.json)
{
"imports": {
    "express": "npm:express@^4.18.2",
    "std/": "https://deno.land/std@0.200.0/"
  }
}

Ecosystem and Library Support

Security: A Modern Concern

Here's where Deno really shines, and Bun follows suit:

Deno Security Example

# Deno requires explicit permissions
deno run server.ts
# ❌ Error: Requires network access

deno run --allow-net server.ts  
# ✅ Can make network requests

deno run --allow-net --allow-read=./config server.ts
# ✅ Network + read ./config directory only

# Fine-grained control
deno run \
--allow-net=api.example.com:443 \
--allow-read=./uploads \
--allow-env=NODE_ENV,PORT \
server.ts

When to Choose What: My Real-World Recommendations

"The best JavaScript runtime is the one that gets your project shipped. Node.js for stability, Bun for speed, Deno for security and simplicity."

Quick Decision Framework

The Bottom Line

After months of testing, here's my honest recommendation:

• Starting a new project? Try Bun. It's Node.js but faster, with better TypeScript support.
• Building something secure? Go with Deno. The security model alone is worth it.
• Working on existing code? Stick with Node.js unless performance is a real problem.
• Just learning? Pick any and focus on JavaScript fundamentals first.