Node.js Runtime Shootout - Bun vs Node.js vs Deno Performance Comparison

Objective

Compare the performance characteristics of three modern JavaScript runtimes—Bun 1.0.23, Node.js 20.11.0, and Deno 1.40.0—across various workloads including HTTP serving, cold starts, module resolution, and database operations.

Test Setup

Hardware & Environment

• Server: DigitalOcean CPU-Optimized Droplet (8 vCPU, 16GB RAM)
• OS: Ubuntu 22.04 LTS
• Disk: NVMe SSD
• Network: 1Gbps connection

Runtime Versions

• Bun: 1.0.23 (released January 2025)
• Node.js: 20.11.0 LTS with V8 11.8
• Deno: 1.40.0 with V8 12.1

Test Methodology

All benchmarks were run using:

• Load Testing: wrk with 12 threads, 400 connections, 30-second duration
• Cold Start: Average of 100 runs with cleared system cache
• Module Resolution: Average of 1,000 iterations
• Database: PostgreSQL 15 with connection pooling

Each test was repeated 5 times, results are median values with p95 percentiles.

HTTP Server Performance

Simple "Hello World" Server

// Bun
Bun.serve({
  port: 3000,
  fetch() {
    return new Response("Hello World");
  },
});

// Node.js
import http from 'http';
http.createServer((req, res) => {
  res.end("Hello World");
}).listen(3000);

// Deno
Deno.serve({ port: 3000 }, () => new Response("Hello World"));

Results:

Winner: Bun (82% faster than Node.js)

JSON API Endpoint

// All runtimes - similar implementation
const data = { users: Array(100).fill({ name: "John", age: 30 }) };
// Return JSON response

Results:

Winner: Bun (79% faster, 27% less memory)

File Upload Processing

Tested with 10MB file uploads:

Winner: Bun (39% faster than Node.js)

Startup Time

Cold start time from shell invocation to first HTTP response:

Winner: Bun (3.4x faster cold start)

Module Resolution

Time to resolve and load 1,000 modules:

Notes:

• Bun has native TypeScript support
• Node.js requires transpilation for TypeScript
• Deno has built-in TypeScript support

Winner: Bun (6.6x faster for npm packages)

Database Operations

PostgreSQL query performance using native drivers:

Simple SELECT Query (1,000 iterations)

Prepared Statements

Winner: Bun (30% faster, 25% less memory)

Real-World Application Test

Full-stack CRUD API with:

• Express-style routing
• PostgreSQL database
• JWT authentication
• Request validation
• Logging middleware

Load Test Results (50,000 mixed requests):

Winner: Bun (75% faster than Node.js, 52% faster than Deno)

Memory Usage

Idle memory consumption and under load:

Winner: Bun (38% less memory than Node.js)

Package Ecosystem Compatibility

Tested top 100 npm packages:

Notable incompatibilities:

• Bun: Some native addons, bcrypt (use @node-rs/bcrypt instead)
• Deno: Many packages require npm: specifier or compatibility layer

Developer Experience

TypeScript Support

Built-in Tools

Installation Time

Installing express and 50 dependencies:

Interpretation

Key Findings

1. Raw Performance: Bun dominates HTTP serving (82% faster) and cold starts (3.4x faster)
2. Memory Efficiency: Bun uses 38% less memory than Node.js under load
3. Ecosystem: Node.js has perfect npm compatibility, Bun at 97%, Deno at 78%
4. Developer Experience: Bun and Deno offer native TypeScript, Node.js requires tooling

When to Choose Bun

✅ High-traffic APIs requiring maximum throughput ✅ Serverless functions with cold start sensitivity ✅ TypeScript projects without build complexity ✅ Greenfield projects with modern dependencies ✅ Cost optimization (fewer servers needed)

When to Choose Node.js

✅ Enterprise projects requiring LTS support ✅ Complex npm dependencies with native addons ✅ Teams with existing Node.js expertise ✅ Applications using Node.js-specific features ✅ Maximum ecosystem compatibility required

When to Choose Deno

✅ Security-focused applications (sandboxed by default) ✅ TypeScript-first development ✅ Projects benefiting from built-in tooling ✅ Web-standard-aligned codebases ✅ Avoiding npm package hell

Caveats

• Bun is still pre-1.0 stability for some features
• Some native Node.js modules may not work in Bun
• Production battle-testing favors Node.js (15+ years) over Bun (<2 years)
• Benchmarks measure synthetic workloads; real-world results may vary
• Memory measurements exclude OS-level allocations

Recommendations

For new projects in 2025:

• Start with Bun if performance is critical and you can test thoroughly
• Use Node.js if you need maximum stability and ecosystem support
• Choose Deno if security and TypeScript are top priorities

For existing projects:

• Benchmark your specific workload before migrating
• Bun's drop-in Node.js compatibility makes A/B testing easy
• Consider gradual migration starting with performance-critical services

Reproducibility

All benchmark code available at: https://github.com/staticblock/nodejs-runtime-benchmarks-2025

Running the Benchmarks

# Clone repository
git clone https://github.com/staticblock/nodejs-runtime-benchmarks-2025
cd nodejs-runtime-benchmarks-2025

# Install runtimes
./scripts/install-runtimes.sh

# Run all benchmarks
./scripts/run-benchmarks.sh

# View results
cat results/summary.json

Last Updated: January 22, 2025 Runtime Versions Tested: Bun 1.0.23, Node.js 20.11.0, Deno 1.40.0