🚀 Supercharging APIs with Bun: A Quickstart Guide

APIs are the backbone of modern applications, powering data exchanges across devices and platforms. But creating them doesn’t have to involve heavy dependencies or slow workflows. Enter Bun 🌀—a modern JavaScript runtime that’s super fast, lightweight, and packed with developer-friendly features.

✨ What is Bun?

Bun is a cutting-edge JavaScript runtime, written in the low-level systems programming language Zig. It’s designed for speed ⚡ and efficiency, offering a unified environment for developing modern web applications.

🔑 Key Features of Bun*:*

• Blazing Fast 🚄: Faster startup times and runtime performance compared to Node.js.

• Built-In HTTP Server 🌐: No need for frameworks like Express or Koa for basic API needs.

• Native TypeScript Support 📘: Run TypeScript files out of the box.

• Improved Developer Experience 🛠️: Comes with a package manager, bundler, and more.

How to Install Bun

Installing Bun is a breeze 🌬️. Just run this command in your terminal:

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

Once installed, verify that Bun is working by checking its version:

bun --version

You’re all set! ✅ If you’re on Windows 🪟, use WSL (Windows Subsystem for Linux) to install and run Bun.

🛠️ Creating Your First API Endpoint with Bun

Let’s build a simple API that responds with a “Hello, Bun!” message. 💬

Step 1: Initialize a Bun Project

Start by creating a new Bun project:

create app my-bun-api
cd my-bun-api

This sets up a project folder with all the essentials. 🗂️

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Step 2: Build the Server

Bun includes a built-in HTTP server (Bun.serve) that simplifies API development. Open the src/index.ts file (or create it if it doesn’t exist), and add this code:

Bun.serve({
  fetch(req) {
    return new Response("Bun!");
  },
});

serve({
  port: 3000, 
  fetch(request) {
    const url = new URL(request.url);
    if (url.pathname === "/api/hello" && request.method === "GET") {
      return new Response(
        JSON.stringify({ message: "Hello, Bun!" }),
        { headers: { "Content-Type": "application/json" } }
      );
    }
    if (url.pathname === "/api/greet" && request.method === "POST") {
      return request.json().then((body) => {
        const name = body.name || "Guest"; 
        return new Response(
          JSON.stringify({ message: `Hello, ${name}!` }),
          { headers: { "Content-Type": "application/json" } }
        );
      });
    }
    return new Response(
      JSON.stringify({ error: "Not Found" }),
      { status: 404, headers: { "Content-Type": "application/json" } }
    );
  },
});

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Step 3: Start the Bun Server

Run the following command to start the server:

run src/index.ts

Your terminal will display:

Bun is listening on http://localhost:3000 🌟

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Step 4: Test the API Endpoint

Open your browser 🌐 or use curl to test the /api/hello endpoint:

curl http://localhost:3000/api/hello

You’ll get this JSON response:

json{
  "message": "Hello, Bun!"
}

🎉 Congratulations! Your first Bun-powered API is live. 🚀

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🌟 Expanding Your API

Let’s make things more dynamic by creating a personalized greeting endpoint. Add a new /api/greet route that accepts a POST request. Update your src/index.ts file:

if (url.pathname === "/api/greet" && request.method === "POST") {
  request.json().then((body) => {
    const name = body.name || "Guest"; // Default to "Guest" if no name provided

    return new Response(
      JSON.stringify({ message: `Hello, ${name}!` }),
      { headers: { "Content-Type": "application/json" } }
    );
  });
}

curl -X POST http://localhost:3000/api/greet \
     -H "Content-Type: application/json" \
     -d '{"name": "Bun"}'

json{
  "message": "Hello Bun"
}

Amazing, right? 🌈

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🤔 Why Use Bun for APIs?

1. Speed ⚡: Written in Zig, Bun is optimized for performance, making it faster than traditional runtimes.

2. All-in-One Toolkit 🛠️: With built-in support for HTTP servers, TypeScript, and npm packages, you save time and avoid extra dependencies.

3. Simple Setup 🧑‍💻: Bun’s intuitive design makes it ideal for small projects or prototyping APIs.

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🚀 Take It Further: Challenge Yourself

Here are some ideas to expand your API:

1. 🕒 Current Time Endpoint: Add /api/time to return the current server time.

2. CRUD Operations 📝: Create /api/users to simulate user management (create, read, update, delete).

3. 🔄 String Manipulation: Add /api/reverse to accept a string and return its reversed version.

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🎯 Conclusion

Bun is a game-changer for developers who value speed, simplicity, and flexibility. Its built-in tools and runtime efficiency make it a great choice for creating APIs without the overhead of traditional frameworks.

🌟 Whether you’re building a small project or exploring new tools, Bun is worth adding to your toolkit. So, what are you waiting for? Fire up Bun and start building amazing APIs today! 🚀

Got questions or tips? Drop a comment below! Let’s keep the conversation going. 💬