Three Runtimes, One Language

JavaScript on the server has never had more options — or more confusion. In 2026, developers choosing a backend JS runtime face a genuinely competitive three-way race:

• Node.js 24 — the incumbent with 15 years of ecosystem baggage and battle-tested production pedigree
• Deno 2 — Ryan Dahl’s redemption arc, now with Node.js compatibility and the JSR package registry
• Bun 1.x — the speed-obsessed newcomer built on JavaScriptCore, aiming to replace the entire JS toolchain

This isn’t a “which is best” post — each runtime has a legitimate place in the ecosystem. This is a guide to making the right choice for your use case.

Photo by Markus Spiske on Unsplash

The Quick Comparison

Node.js 24: The Mature Giant

Node.js 24 (released April 2026) ships with:

• V8 12.8 — the latest engine with Maglev JIT on by default
• node:sqlite — built-in SQLite module (no more better-sqlite3)
• Type stripping — run .ts files directly with --experimental-strip-types
• Permission Model — a Deno-inspired, opt-in sandbox (still experimental)

// node:sqlite — finally built-in!
import { DatabaseSync } from 'node:sqlite';

const db = new DatabaseSync(':memory:');
db.exec('CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)');

const insert = db.prepare('INSERT INTO users (name) VALUES (?)');
insert.run('Alice');
insert.run('Bob');

const all = db.prepare('SELECT * FROM users').all();
console.log(all); // [{ id: 1, name: 'Alice' }, { id: 2, name: 'Bob' }]

When to choose Node.js:

• You have an existing large codebase
• Your dependencies use native addons (.node files)
• Your team is deeply familiar with the npm ecosystem
• You need maximum production maturity and enterprise support

Deno 2: The Permission-First Runtime

Deno 2 (released late 2024) was the pivot that made Deno serious:

• Full npm compatibility via npm: specifiers
• Node.js API compatibility via node: module emulation
• JSR (JavaScript Registry) — a TypeScript-first, security-reviewed package registry
• deno compile — bundle your app to a single self-contained executable

// Deno 2: security by default
// This script needs --allow-net and --allow-read to run

const response = await fetch("https://api.example.com/data");
const data = await response.json();

// Write to filesystem — requires explicit --allow-write
await Deno.writeTextFile("output.json", JSON.stringify(data, null, 2));
console.log("Done!");

Run with scoped permissions:

deno run \
  --allow-net=api.example.com \
  --allow-write=./output.json \
  main.ts

JSR: A Better npm?

JSR deserves special attention. Unlike npm, every package on JSR:

• Must be TypeScript (or provide full type declarations)
• Is scored for documentation quality
• Is scoped by default (@scope/package)
• Supports multiple runtimes (Deno, Node, Bun, Cloudflare Workers)

# Add a JSR package to a Node.js project
npx jsr add @std/datetime

# Add to Deno project
deno add @std/datetime

When to choose Deno:

• Security is a top concern (financial services, healthcare)
• You want modern TypeScript-first development
• You’re deploying to Deno Deploy (edge runtime with zero config)
• You want the deno compile single-binary distribution story

Bun: Speed as a Philosophy

Bun’s thesis is that JavaScript tooling is too slow and too fragmented. Instead of a runtime, Bun is a complete JavaScript toolkit in a single binary:

• Runtime (JavaScriptCore-based)
• Package manager (faster than pnpm in most benchmarks)
• Bundler (faster than esbuild for most configs)
• Test runner
• TypeScript transpiler

HTTP Server Performance

Bun’s Bun.serve() consistently leads benchmarks:

// Bun HTTP server
const server = Bun.serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);
    
    if (url.pathname === "/health") {
      return new Response("OK");
    }
    
    if (url.pathname === "/json") {
      return Response.json({ 
        message: "Hello from Bun!",
        timestamp: Date.now()
      });
    }
    
    return new Response("Not Found", { status: 404 });
  },
});

console.log(`Listening on http://localhost:${server.port}`);

Benchmark results (requests/sec, simple JSON endpoint, Apple M3 Pro):

Bun’s SQLite

import { Database } from "bun:sqlite";

const db = new Database("mydb.sqlite");
const query = db.query("SELECT * FROM users WHERE age > $age");
const users = query.all({ $age: 18 });

When to choose Bun:

• Startup time matters (CLI tools, lambdas, edge functions)
• You want to drop npm/yarn/pnpm/esbuild/jest in one move
• You’re starting fresh with no legacy constraints
• Your team values speed of development over ecosystem maturity

Real-World Decision Framework

Building an API/microservice?

• Need maximum ecosystem compat → Node.js + Fastify or Hono
• Need security isolation → Deno + Oak/Hono
• Need maximum throughput → Bun + Elysia

Building a CLI tool?

• Distributing as binary → Deno (deno compile) or Bun (bun build --compile)
• Publishing to npm → Node.js (widest install base)

Serverless/Edge functions?

• Cloudflare Workers → All three work, Deno’s API closest to WinterCG spec
• Deno Deploy → Deno obviously
• AWS Lambda → Node.js (official runtime), Bun (custom runtime layer)

Monorepo + full-stack?

• Next.js/Remix → Node.js or Bun (better compatibility)
• Fresh (Deno) → Deno

Interoperability in 2026

The good news: all three runtimes are converging on the WinterCG (Web-interoperable Runtimes Community Group) standard. This means:

• fetch, Request, Response — identical across all three
• URL, URLSearchParams — standardized
• crypto.subtle — identical Web Crypto API
• ReadableStream, WritableStream — standard Streams API

Libraries that target WinterCG work on all three runtimes. Hono, for example, is a popular framework that runs identically on Node.js, Deno, Bun, and Cloudflare Workers.

Conclusion

Stop asking which runtime is “best” and start asking which runtime is best for your context:

• Node.js 24 is the safe, mature choice with the most ecosystem support
• Deno 2 is the right choice when security, TypeScript DX, and modern tooling matter
• Bun is the right choice when speed — of runtime and of developer tooling — is the priority

In 2026, you can also mix runtimes per service in a microservices architecture. WinterCG compatibility means sharing business logic across them is increasingly tractable.

References:

• Node.js Changelog
• Deno 2 Release Notes
• Bun Documentation
• JSR Registry
• WinterCG

이 글이 도움이 되셨다면 공감 및 광고 클릭을 부탁드립니다 :)