Dev Note

Bun 2.0 vs Node.js vs Deno 2: The Ultimate JavaScript Runtime Comparison in 2026
Three years ago, Bun burst onto the scene with mind-bending benchmark numbers. Today in 2026, all three major JavaScript runtimes have matured significantly. Bun 2.0 shipped in late 2025, Deno 2 landed with npm compatibility, and Node.js 24 continues to evolve.
Which one should you use? Let’s find out — with real benchmarks and real-world analysis.
Photo by Clément Hélardot on Unsplash
The Landscape in 2026
Runtime
      Version
      Engine
      Release Cycle
      License
    
Node.js
      24.x LTS
      V8
      6-month major
      MIT
    
Deno
      2.3
      V8
      Monthly
      MIT
    
Bun
      2.0
      JavaScriptCore (WebKit)
      ~Quarterly
      MIT
    
All three are MIT licensed. All three run TypeScript natively (though with different approaches). All three support npm packages to varying degrees.
Performance Benchmarks
HTTP Server Throughput
Testing a simple JSON API server with wrk (64 connections, 30 seconds):
# Node.js 24
wrk -t4 -c64 -d30s http://localhost:3000/api/users
# Deno 2.3
wrk -t4 -c64 -d30s http://localhost:3001/api/users
# Bun 2.0
wrk -t4 -c64 -d30s http://localhost:3002/api/users
Results (requests/second):
Runtime
      RPS
      Latency P99
      Memory (baseline)
    
Bun 2.0
      187,432
      2.1ms
      42 MB
    
Deno 2.3
      134,891
      3.8ms
      38 MB
    
Node.js 24
      98,234
      5.2ms
      67 MB
    
Test: Simple { users: [...] } JSON response, MacBook M3 Pro
Bun still wins on raw HTTP throughput — significantly. Node.js has improved but still lags.
Startup Time
# Cold start time for a simple HTTP server
time node server.js        # 187ms
time deno run server.ts    # 64ms  
time bun server.ts         # 22ms
Bun’s startup time advantage matters enormously for:
Serverless functions (Lambda, Cloudflare Workers alternative)
CLI tools
Test runners
File I/O
// Read 1000 files, each 10KB
const files = await Promise.all(
  Array.from({ length: 1000 }, (_, i) =>
    fs.promises.readFile(`./data/file-${i}.txt`, 'utf-8')
  )
);
Runtime
      Time
    
Bun 2.0
      234ms
    
Node.js 24
      412ms
    
Deno 2.3
      389ms
    
SQLite Performance
Bun has a first-class built-in SQLite driver:
// Bun - built-in, zero deps
import { Database } from "bun:sqlite";
const db = new Database("app.db");
db.exec("CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT)");
const insert = db.prepare("INSERT INTO users (name) VALUES (?)");
const selectAll = db.prepare("SELECT * FROM users");
// Bulk insert 100k rows
const insertMany = db.transaction((users) => {
  for (const user of users) insert.run(user);
});
const users = Array.from({ length: 100_000 }, (_, i) => `User ${i}`);
const start = performance.now();
insertMany(users);
const elapsed = performance.now() - start;
console.log(`Inserted 100k rows in ${elapsed.toFixed(0)}ms`);
// Bun: ~180ms
// Node.js (better-sqlite3): ~420ms
TypeScript Experience
Bun 2.0
# Just run TypeScript directly — no build step
bun run server.ts
# Type checking (uses tsc under the hood)
bun tsc --noEmit
Bun transpiles TypeScript using its own transpiler (not tsc), which is extremely fast but skips type checking by default. For production, you still want tsc for type safety.
// Works without any tsconfig.json
const greet = (name: string): string => `Hello, ${name}!`;
console.log(greet("World"));
Deno 2.3
Deno has the best TypeScript experience out of the box:
# Type checks AND runs
deno run --check server.ts
# Full TypeScript support including decorators
deno check server.ts
Deno’s LSP integration in VS Code is excellent. It handles imports, types, and module resolution without any configuration.
Node.js 24
# Requires tsx, ts-node, or compilation
npx tsx server.ts
# Or with experimental flag (Node.js 24)
node --experimental-strip-types server.ts  # Still experimental!
Node.js is still behind on native TypeScript. The --experimental-strip-types flag added in Node.js 22 removes type annotations at runtime (no type checking), which is useful but limited.
Package Management & Ecosystem
npm Compatibility
Feature
      Bun 2.0
      Deno 2.3
      Node.js 24
    
npm install
      ✅ Full
      ✅ Full
      ✅ Full
    
package.json
      ✅
      ✅
      ✅
    
node_modules
      ✅
      ✅ (optional)
      ✅
    
Lockfile
      bun.lock
      deno.lock
      package-lock.json
    
Workspaces
      ✅
      ✅
      ✅
    
Deno 2 was a game-changer: full npm compatibility meant the “but ecosystem!” argument against Deno evaporated.
Install Speed
# Installing React + 50 common dependencies
time npm install    # 42s
time yarn install   # 38s
time pnpm install   # 19s
time bun install    # 3.2s  ← 10-13x faster
Bun’s package manager is genuinely remarkable. The binary lockfile format and aggressive parallelism make it dramatically faster.
Bun’s Built-in Tools
Bun ships with:
# Package manager
bun install / bun add / bun remove
# Script runner
bun run build
bun run test
# Test runner (Jest-compatible!)
bun test
# Bundler
bun build ./src/index.ts --outdir ./dist
# TypeScript runner
bun run server.ts
# REPL
bun repl
This replaces: npm/yarn/pnpm, Jest/Vitest, esbuild/webpack/rollup, ts-node/tsx, nodemon — all in one binary.
Web Standards Compliance
Deno leads in web standards:
// Deno — built-in Web APIs, no polyfills needed
const response = await fetch("https://api.example.com/data");
const data = await response.json();
// Web Crypto — native
const key = await crypto.subtle.generateKey(
  { name: "AES-GCM", length: 256 },
  true,
  ["encrypt", "decrypt"]
);
// URLPattern — native
const pattern = new URLPattern({ pathname: "/users/:id" });
const match = pattern.exec("/users/123");
console.log(match?.pathname.groups.id); // "123"
// Streams API — native
const stream = new ReadableStream({
  start(controller) {
    controller.enqueue("Hello");
    controller.enqueue(" World");
    controller.close();
  }
});
All three runtimes now support fetch, WebSocket, crypto, and ReadableStream. Deno had them first; Bun and Node.js caught up.
Security Model
Deno’s Permission System
Deno’s explicit permissions remain unique:
# Deny everything by default, grant explicitly
deno run \
  --allow-net=api.example.com \
  --allow-read=/tmp/data \
  --allow-env=API_KEY,DATABASE_URL \
  server.ts
# Any other access = permission denied
# Attempt to read /etc/passwd → denied
# Attempt to connect to unknown host → denied
// You can also request permissions at runtime
const status = await Deno.permissions.request({ name: "read", path: "/tmp" });
if (status.state === "granted") {
  const content = await Deno.readTextFile("/tmp/data.txt");
}
This is a genuine security advantage for running untrusted code (plugins, user scripts, build tools).
Bun and Node.js
Both use Node.js’s traditional model: full system access by default. Bun 2.0 added a --smol mode for memory restriction but no fine-grained permissions.
Framework Ecosystem in 2026
Works on all three:
Hono — fast, lightweight, runs everywhere
Remix — full-stack, adapts to runtime
Elysia — Bun-first, TypeScript-native
Bun-optimized:
// Elysia + Bun — best TypeScript DX in 2026
import { Elysia, t } from "elysia";
import { swagger } from "@elysiajs/swagger";
const app = new Elysia()
  .use(swagger())
  .get("/users/:id", ({ params: { id } }) => ({
    id,
    name: "Alice"
  }), {
    params: t.Object({ id: t.String() }),
    response: t.Object({ id: t.String(), name: t.String() })
  })
  .listen(3000);
console.log(`🦊 Running at ${app.server?.hostname}:${app.server?.port}`);
Deno-native:
// Fresh 2 — Deno's full-stack framework
// routes/users/[id].tsx
import type { PageProps } from "$fresh/server.ts";
export default function UserPage({ params }: PageProps) {
  return (
    <div>
      <h1>User {params.id}</h1>
    </div>
  );
}
Node.js-native (but works everywhere):
Express, Fastify, Nest.js, Next.js — still work best on Node.js due to ecosystem assumptions
When to Use Each
Choose Bun 2.0 when:
✅ Performance is critical (API servers, real-time systems)
✅ You want one tool for everything (install + run + test + bundle)
✅ SQLite is a good database choice
✅ Building CLI tools
✅ Monorepo with many packages (install speed!)
✅ Starting fresh with TypeScript
Choose Deno 2.3 when:
✅ Security is paramount (plugin systems, running user code)
✅ You want the best TypeScript developer experience
✅ Building for edge/serverless (Deno Deploy)
✅ Web standards compliance matters
✅ You prefer explicit dependency URLs
✅ Building standalone executables (deno compile)
Choose Node.js 24 when:
✅ Existing codebase with Node.js assumptions
✅ Mature team with Node.js expertise
✅ Frameworks that don’t support Bun/Deno (rare in 2026)
✅ Enterprise environments requiring LTS guarantees
✅ Native addons (N-API) are required
✅ Maximum npm package compatibility
Real-World Migration: Node.js → Bun
Most Node.js apps work with Bun out of the box:
# In an existing Node.js project
bun install  # reads package.json, creates bun.lockb
# Run your existing scripts
bun run start
bun run build
bun run test  # Jest tests work with Bun's test runner!
# Check compatibility
bun --version  # 2.0.x
node --version  # (no longer needed for most things)
Common issues:
Native addons (.node files) — may not work, check Bun’s compatibility list
__dirname / __filename — works in Bun (CJS compatibility)
Worker threads — supported but minor API differences
crypto module — Bun uses Web Crypto, some Node crypto APIs differ
The Verdict
Criteria
      Bun 2.0
      Deno 2.3
      Node.js 24
    
Performance
      🥇
      🥈
      🥉
    
TypeScript DX
      🥈
      🥇
      🥉
    
Ecosystem
      🥇
      🥈
      🥇
    
Security
      🥉
      🥇
      🥉
    
Maturity
      🥈
      🥈
      🥇
    
All-in-one tooling
      🥇
      🥈
      🥉
    
Enterprise support
      🥉
      🥉
      🥇
    
My take in 2026:
New projects: Bun 2.0 with Elysia or Hono
Security-critical: Deno 2 on Deno Deploy
Enterprise/existing: Node.js 24 LTS, migrate to Bun when ready
Monorepos: Bun (install speed alone justifies it)
The JavaScript runtime war isn’t over, but competition has made all three dramatically better. Node.js is faster, Deno has npm, and Bun is more stable than ever. Pick the right tool for your context — and revisit the decision every year.
References:
Bun 2.0 Release Notes
Deno 2 Documentation
Node.js 24 Release

Bun 2.0 vs Node.js vs Deno 2: The Ultimate JavaScript Runtime Comparison in 2026

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