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

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):

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')
  )
);

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

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:

1. Native addons (.node files) — may not work, check Bun’s compatibility list
2. __dirname / __filename — works in Bun (CJS compatibility)
3. Worker threads — supported but minor API differences
4. crypto module — Bun uses Web Crypto, some Node crypto APIs differ

The Verdict

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

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