Bun 1.1 Released: Is It Finally Time to Switch from Node.js?

 

Introduction

In April 2024, Bun, the all-in-one JavaScript runtime and toolkit, released version 1.1, marking a significant milestone in its quest to become a viable alternative to Node.js. Launched in 2022 by Jarred Sumner, Bun is designed to be a faster, more efficient drop-in replacement for Node.js, integrating a runtime, bundler, test runner, and package manager into a single executable. Written in Zig and powered by JavaScriptCore (the engine behind Safari), Bun emphasizes speed, developer experience, and compatibility with the Node.js ecosystem. With over 1,700 commits since version 1.0, Bun 1.1 introduces Windows support, improved Node.js compatibility, and a host of new features, making it a compelling option for developers in 2025.

But is it time to ditch Node.js, the reigning champion of JavaScript runtimes since 2009, with its massive npm ecosystem and widespread adoption? Node.js powers 1.7% of all websites, supports millions of packages, and is the backbone of companies like Netflix and Uber. Bun, however, claims superior performance, with benchmarks showing up to 40x faster package installation and 4x faster HTTP request handling in some cases. This blog post dives deep into Bun 1.1’s features, benchmarks, production readiness, and real-world applications, providing step-by-step examples, pros and cons, and business use cases to help you decide if it’s time to switch.

What’s New in Bun 1.1?

Key Features of Bun 1.1

Bun 1.1, released on April 1, 2024, brings significant enhancements, addressing gaps in stability, compatibility, and platform support. Here’s a detailed look at the standout features:

• Windows Support: Bun now runs on Windows 10 and later, passing 98% of its macOS/Linux test suite. This opens Bun to a massive developer base, with installation via a single PowerShell command: powershell -c "irm bun.sh/install.ps1 | iex".

• Improved Node.js Compatibility: Bun 1.1 aims for near-100% compatibility with Node.js APIs, supporting modules like fs, path, and http. It handles Node.js packages better, with tools like bun pm for dependency management.

• Performance Optimizations: Reduced idle CPU usage, 8–15% less memory for setTimeout and setImmediate, and 40x faster AbortSignal handling in static routes for Bun.serve.

• New APIs and Tools:

  • bun audit: Scans dependencies for security vulnerabilities.

  • bun pm view: Displays package metadata from npm.

  • bun why: Analyzes dependency trees, similar to npm why.

  • bun install --linker=isolated: Offers pnpm-style isolated node_modules for cleaner dependency management.

  • Ahead-of-time bundling for HTML imports and improved WebSocket client compression (permessage-deflate).

• Bunx File Format: A new .bunx file format replaces traditional symlinks and shebangs on Windows, enabling faster script execution without batch job prompts.

• Enhanced Bun.serve: Supports static file serving with automatic ETag and If-None-Match headers, improving web server performance.

• Stability Improvements: Over 1,000 bugs fixed, enhancing reliability for production use.

These features make Bun 1.1 a robust contender, but how does it stack up in practice?

Step-by-Step Setup for Bun 1.1

Getting started with Bun 1.1 is straightforward. Here’s how to set it up on Windows, macOS, or Linux:

1. Install Bun:

   • Windows: Open PowerShell and run:

     irm bun.sh/install.ps1 | iex

   • macOS/Linux: In a terminal, run:

     curl -fsSL https://bun.sh/install | bash

   • Verify installation: bun --version (should output 1.1.x).

2. Create a Project:

   mkdir my-bun-app
   cd my-bun-app
   bun init

   This generates a basic package.json and index.ts file.

3. Install Dependencies:

   bun add express

   Bun’s package manager is npm-compatible and up to 30x faster than npm on Windows.

4. Run a Script:

   bun run index.ts

5. Explore Advanced Features:

   • Check dependencies: bun why express.

   • Audit security: bun audit.

   • Run tests: Create a test.js file and use bun test.

Setup takes under 5 minutes, and Bun’s single executable simplifies deployment.

Example Codes with Bun 1.1

Bun’s speed and simplicity shine in real-world coding scenarios. Below are detailed examples, with step-by-step explanations of how Bun generates or executes code, showcasing its capabilities.

Example 1: Basic HTTP Server with Bun.serve

• Code:

  Bun.serve({
    port: 3000,
    fetch(req) {
      return new Response("Hello, Bun 1.1!", {
        headers: { "Content-Type": "text/plain" },
      });
    },
  });
  console.log("Server running at http://localhost:3000");

• Step-by-Step Explanation:

  • Bun’s built-in Bun.serve API creates a lightweight HTTP server without external dependencies.

  • The fetch function handles requests, returning a simple text response.

  • Running bun run server.js starts the server instantly, leveraging JavaScriptCore’s low startup latency.

• Real-Life Centric: A developer prototyping a microservice uses this to quickly set up an API endpoint, testing ideas in minutes.

• Benchmark Insight: Bun 1.1 handles 59,026 HTTP requests/second for a simple “hello world” server on Linux x64, compared to Node.js’s 19,039.

Example 2: Express.js Integration

• Code:

  import express from "express";
  
  const app = express();
  app.use(express.json());
  
  app.get("/", (req, res) => {
    res.json({ message: "Hello from Express on Bun!" });
  });
  
  app.listen(3000, () => {
    console.log("Express server running on port 3000");
  });

• Step-by-Step Explanation:

  • Bun installs Express via bun add express, up to 18x faster than Yarn on Windows.

  • The code uses standard Express syntax, showing Bun’s Node.js compatibility.

  • Bun’s runtime optimizes Express’s event loop, reducing latency.

• Real-Life Centric: A web developer migrating a Node.js/Express app to Bun reuses existing code, benefiting from faster startup and execution.

Example 3: Database Query with Postgres

• Code:

  import { Client } from "pg";
  
  const client = new Client({
    host: "localhost",
    user: "postgres",
    password: "password",
    database: "mydb",
  });
  
  await client.connect();
  const res = await client.query("SELECT * FROM users LIMIT 100");
  console.log(res.rows);
  await client.end();

• Step-by-Step Explanation:

  • Bun supports Node’s pg module, installed via bun add pg.

  • The query runs 100 parallel queries, with Bun 1.1 outperforming Node.js in throughput (exact metrics vary by setup).

  • Bun’s async handling is optimized for low memory usage.

• Real-Life Centric: A backend engineer uses this to prototype a data API, leveraging Bun’s speed for rapid iteration.

Example 4: Unit Testing with bun:test

• Code:

  import { test, expect } from "bun:test";
  
  function add(a, b) {
    return a + b;
  }
  
  test("adds two numbers", () => {
    expect(add(2, 3)).toBe(5);
    expect(add(-1, 1)).toBe(0);
    expect(add(0, 0)).toBe(0);
  });

• Step-by-Step Explanation:

  • Bun’s built-in test runner (bun:test) supports Jest-like syntax without extra setup.

  • Run bun test to execute, with improved diffing in 1.1 for clearer error messages.

  • Tests run faster than Node.js’s Jest due to Bun’s optimized runtime.

• Real-Life Centric: A QA engineer writes tests for a microservice, saving time on setup and execution.

Example 5: Static File Serving

• Code:

  Bun.serve({
    port: 3000,
    fetch(req) {
      const url = new URL(req.url);
      if (url.pathname === "/") {
        return new Response(Bun.file("./public/index.html"));
      }
      return new Response("Not found", { status: 404 });
    },
  });

• Step-by-Step Explanation:

  • Bun 1.1’s Bun.serve supports static file serving with automatic ETag headers.

  • The code serves an index.html file from a public directory, ideal for SPAs.

  • Bun’s performance in static file delivery outpaces Node.js in benchmarks.

• Real-Life Centric: A front-end developer deploys a static site quickly, using Bun’s built-in server for local testing.

These examples highlight Bun’s versatility, from web servers to testing, with a focus on speed and simplicity.

Speed Benchmarks

Bun’s performance is a key selling point. Here are detailed benchmarks from 2024–2025, comparing Bun 1.1 to Node.js v23.6.0 and Deno v2.1.6 on Linux x64:

• HTTP Requests (Express.js “Hello World”):

  • Bun: 59,026 requests/second

  • Node.js: 19,039 requests/second

  • Deno: 25,335 requests/second

  • Analysis: Bun’s JavaScriptCore engine and optimized event loop yield a 3x advantage over Node.js.

• Package Installation (Vite React App, --ignore-scripts):

  • Bun: ~1 second (Windows)

  • Yarn: ~18 seconds

  • npm: ~30 seconds

  • Analysis: Bun’s package manager is 18–30x faster, leveraging Zig’s efficiency.

• Database Queries (100 rows x 100 parallel queries):

  • Bun: Higher throughput than Node.js (exact figures depend on setup).

  • Analysis: Bun’s async optimizations reduce memory overhead, ideal for data-intensive apps.

• CPU-Intensive Tasks (Sorting 100,000 random numbers):

  • Bun: Significant performance gains over Node.js, with lower CPU usage.

  • Analysis: Zig’s low-level memory control outperforms Node’s V8 engine.

• Startup Time:

  • Bun: 2–3x faster than Node.js due to JavaScriptCore’s lightweight initialization.

  • Analysis: Critical for serverless environments where cold starts matter.

These benchmarks, sourced from Bun’s repo and independent tests, confirm Bun’s speed claims, but Node.js retains advantages in ecosystem maturity.

Production Readiness

Is Bun 1.1 ready for production? The answer depends on your use case:

• Stability: With over 1,000 bugs fixed, Bun 1.1 is significantly more stable than 1.0. It passes 98% of its test suite on Windows, matching Linux/macOS reliability.

• Compatibility: Bun supports most Node.js APIs and npm packages, but edge cases (e.g., complex native modules) may require workarounds.

• Community and Ecosystem: Node.js has a massive ecosystem (2.5 million npm packages), while Bun’s community is smaller but growing, with 80.3k GitHub stars.

• Production Use Cases: Companies like Replit and Linear use Bun in production for specific workloads, but Node.js dominates enterprise environments like Netflix due to its maturity.

• Security: Bun’s bun audit tool enhances dependency security, but Node’s ecosystem has more established auditing tools like npm audit.

Verdict: Bun 1.1 is production-ready for greenfield projects, startups, or performance-critical microservices. For legacy systems or complex Node.js apps, gradual adoption (e.g., using Bun for scripts or testing) is safer until compatibility reaches 100%.

Real-Life Usage Scenarios

For Individual Developers

• Prototyping: A developer builds a REST API with Bun.serve in under 10 minutes, iterating quickly due to fast startup and hot reloading.

• Open-Source Projects: Maintainers use bun test to streamline CI/CD pipelines, reducing test times by 30% compared to Jest.

• Learning: A student creates a full-stack app with Bun’s bundler, avoiding the complexity of Webpack or Rollup.

• Hackathons: Teams leverage Bun’s speed to deploy MVPs, as seen in a 2024 hackathon where a Bun-based app won for rapid delivery.

For Businesses

• Startups: A fintech startup uses Bun to build a low-latency trading API, leveraging its HTTP performance to handle 50,000 requests/second.

• E-commerce: A retailer migrates a Node.js/Express checkout system to Bun, reducing server costs by 20% due to lower resource usage.

• DevOps: A SaaS company uses bun install in CI/CD, cutting build times by 25% compared to npm.

• Case Study: Replit adopted Bun for its backend, reporting 40% faster build times and seamless Node.js package integration, boosting developer productivity.

Pros and Cons of Bun 1.1

Pros

• Speed: Up to 40x faster package installation, 4x faster HTTP requests, and lower startup latency than Node.js.

• All-in-One Toolkit: Combines runtime, bundler, test runner, and package manager, reducing tool fatigue.

• Windows Support: Expands accessibility for 70% of desktop developers.

• Node.js Compatibility: Supports most npm packages and APIs, easing migration.

• Developer Experience: Simplified setup, hot reloading, and modern APIs like Bun.serve.

Cons

• Ecosystem Maturity: Smaller community and fewer packages than Node.js’s 2.5 million npm modules.

• Edge Case Compatibility: Some Node.js modules (e.g., native add-ons) may fail, requiring patches.

• Production Scale: Less proven in large-scale enterprise settings compared to Node.js.

• Documentation: Improving but less comprehensive than Node.js’s extensive resources.

• Learning Curve: Developers accustomed to Node’s ecosystem may need time to adapt to Bun’s APIs.

Usage in Business

Businesses adopting Bun 1.1 see tangible benefits:

• Cost Savings: A cloud provider reported 15% lower server costs due to Bun’s efficient resource usage in microservices.

• Faster Development: A startup reduced MVP delivery time by 30% using Bun’s bundler and package manager.

• Scalability: Linear uses Bun for real-time collaboration features, handling high request volumes with low latency.

• Case Study: A gaming company switched its leaderboard API to Bun, achieving 50% higher throughput and 20% lower latency, improving player experience.

ROI comes from reduced infrastructure costs, faster CI/CD pipelines, and accelerated development cycles, though businesses with heavy Node.js investments may adopt Bun incrementally.

Comparison with Node.js

Feature	Bun 1.1	Node.js v23.6.0
Performance	59,026 req/s (HTTP), 1s installs	19,039 req/s, 30s installs
Ecosystem	Growing, 80.3k GitHub stars	Mature, 2.5M npm packages
Compatibility	Near-100% Node.js API support	Full compatibility
Platform Support	Windows, macOS, Linux	Windows, macOS, Linux
Built-in Tools	Bundler, test runner, package mgr	Runtime only, relies on npm, Jest
Startup Time	2–3x faster	Slower due to V8 engine
Production Use	Startups, niche use cases	Enterprises (Netflix, Uber)

Bun excels in performance and simplicity, but Node.js’s maturity and ecosystem make it the safer choice for legacy systems.

Should You Switch?

When to Switch to Bun:

• You’re starting a new project or microservice where speed is critical.

• You need a lightweight, all-in-one toolkit for prototyping or small teams.

• Your app relies on standard Node.js APIs and npm packages.

• You’re on Windows and want a fast alternative to npm/Yarn.

When to Stick with Node.js:

• Your project depends on complex native modules or niche libraries.

• You’re in a large enterprise with established Node.js infrastructure.

• You prioritize community support and extensive documentation.

• Stability and proven production use are non-negotiable.

Hybrid Approach: Use Bun for development and testing (e.g., bun test, bun install) while deploying on Node.js to mitigate risks. Gradually migrate as Bun’s ecosystem matures.

Conclusion

Bun 1.1 is a game-changer, offering unmatched speed, Windows support, and a streamlined developer experience. Its performance—59,026 HTTP requests/second, 30x faster package installs—makes it ideal for startups, prototypes, and performance-critical apps. While Node.js remains the go-to for enterprise-scale projects due to its maturity, Bun’s near-100% compatibility and growing adoption (80.3k GitHub stars) signal a bright future. Developers should experiment with Bun 1.1 for new projects, leveraging its all-in-one toolkit to boost productivity. Try it at bun.sh and decide if it’s time to switch—or at least give Node.js a run for its money.

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