Building API Endpoints with Bun 🎉

If you’ve been exploring the JavaScript ecosystem recently, chances are you’ve stumbled upon Bun – the new, fast, and lightweight runtime designed to compete with Node.js and Deno. But did you know it’s also fantastic for creating API endpoints? Whether you’re building a simple app or a full-blown backend, Bun has you covered! Let’s dive into how to set up an API endpoint using Bun.

---

Why Pick Bun? 🌟

Before diving in, let’s look at what makes Bun stand out:

1. Blazing Fast: Bun is designed for speed, outperforming many other runtimes in various benchmarks. 🏆

2. All-in-One: It packs a bundler, transpiler, and task runner, streamlining your workflow. 📦

3. Developer-Friendly: Enjoy a seamless experience with minimal setup required. ✨

Real-World Use Cases 🌍

Bun is not just a theoretical tool; it has practical applications across various domains:

• Microservices Architecture: Its lightweight nature makes Bun ideal for microservices where speed and resource efficiency are critical.

• Serverless Functions: Developers can deploy Bun-based functions that execute quickly in serverless environments, reducing latency.

• Rapid Prototyping: Startups and developers can leverage Bun's simplicity to quickly build and iterate on APIs, facilitating faster product development.

• Real-Time Applications: With its performance capabilities, Bun is suitable for real-time applications like chat services or live data feeds.

---

Setting Up Bun 🚀

First things first, let’s make sure you have Bun installed. If you haven’t done that yet, it’s just a one-liner:

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

Once installed, you’re ready to create your API project.

---

Step 1: Create a New Bun Project 🏢

Let’s kick things off by initializing a new Bun project. Run the following command:

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

This creates a project scaffold for you. Feel free to explore the files – it’s clean and simple! 🍄

---

Step 2: Setting Up the API Endpoint 🔍

For our API, we’ll create a basic endpoint that returns a JSON response. Open the index.ts file and add this:

serve({
  port: 3000, // Your API will run on localhost:3000 🌎
  fetch(req) {
    return new Response(
      JSON.stringify({ message: "Hello, Bun API! 👋" }),
      {
        headers: {
          "Content-Type": "application/json",
        },
      }
    );
  },
});

This code does the following:

• Starts a server on port 3000. 🚨

• Defines a simple fetch handler that returns a JSON response. 📊

---

Step 3: Running Your API ⚡

To start your server, simply run:

bun run index.js

Head over to your browser and navigate to http://localhost:3000. You should see this:

{
  "message": "Hello, Bun API! 👋"
}

Congratulations! You just created your first API endpoint using Bun. 🎉

---

Step 4: Adding More Endpoints ➕

Want to expand your API? Let’s add another endpoint for getting user data. Update your fetch function:

serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);

    if (url.pathname === "/users") {
      return new Response(
        JSON.stringify({ users: ["Alice", "Bob", "Charlie"] }),
        {
          headers: {
            "Content-Type": "application/json",
          },
        }
      );
    }

    return new Response("Not Found", { status: 404 });
  },
});

Now, if you visit http://localhost:3000/users, you’ll get:

{
  "users": ["Alice", "Bob", "Charlie"]
}

---

Step 5: Keeping It Modular 🔧

As your API grows, managing everything in one file can get messy. Split your routes into separate files for better organization:

routes/users.ts:

export function getUsers() {
  return new Response(
    JSON.stringify({ users: ["Alice", "Bob", "Charlie"] }),
    {
      headers: { "Content-Type": "application/json" },
    }
  );
}

index.ts:

import { serve } from "bun";
import { getUsers } from "./routes/users";

serve({
  port: 3000,
  fetch(req) {
    const url = new URL(req.url);

    if (url.pathname === "/users") {
      return getUsers();
    }

    return new Response("Not Found", { status: 404 });
  },
});

---

Comparison with Other Runtimes ⚖️

When comparing Bun to other popular runtimes like Node.js and Deno, several key differences emerge:

Wrapping Up 🏋‍♂

Bun makes creating APIs incredibly straightforward. Its built-in speed, simplicity, and developer-friendly features make it a fantastic choice for modern web development. So why not give it a try? Your next API project might just become your favorite! ✨