API Endpoint Using Bun
How to Create API Endpoints Using Bun

How to Create API Endpoints Using Bun

Ravi Vira's photo
Ravi Vira
·

2 min read

Introduction
Bun is an incredibly fast JavaScript runtime that is gaining traction for its speed and simplicity. With built-in support for various features like HTTP servers, file watching, and transpilation, Bun makes building APIs a breeze. In this blog, we'll go through the steps to create a simple API endpoint using Bun.

What is Bun?
Bun is a modern JavaScript runtime built from the ground up to be fast. It includes a bundler, a task runner, and a test runner, making it a one-stop solution for JavaScript and TypeScript development.

Why Use Bun for APIs?

  • Speed: Bun is built in Zig, which gives it lightning-fast performance.

  • Built-in HTTP support: No need to install extra libraries like Express.

  • Developer-friendly: Built-in TypeScript and JSX support out of the box.

Step 1: Install Bun

Before we start, you need to have Bun installed. If you don’t have it yet, you can install it by running:

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

Verify the installation:

bashCopyEditbun --version

Step 2: Create a New Bun Project

Run the following command to initialize a new Bun project:

bashCopyEditbun create my-api

Navigate to the project directory:

bashCopyEditcd my-api

Step 3: Set Up Your API Server

Bun provides a built-in HTTP server, so there's no need for additional dependencies. Let's create a simple API endpoint. Open index.js (or create one if it doesn't exist) and add the following code:

typescriptCopyEditimport { serve } from "bun";

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

    if (url.pathname === "/api") {
      return new Response(
        JSON.stringify({ message: "Hello from Bun API!" }),
        {
          headers: { "Content-Type": "application/json" },
        }
      );
    }

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

console.log(`Server running at http://localhost:${server.port}`);

Step 4: Run Your Server

Start the server by running:

bashCopyEditbun index.ts

Visit http://localhost:3000/api in your browser or use a tool like Postman. You should see the JSON response:

jsonCopyEdit{
  "message": "Hello from Bun API!"
}

Step 5: Extend Your API

You can easily add more endpoints. For example:

typescriptCopyEditif (url.pathname === "/api/greet") {
  const name = url.searchParams.get("name") || "Guest";
  return new Response(
    JSON.stringify({ message: `Hello, ${name}!` }),
    { headers: { "Content-Type": "application/json" } }
  );
}

Conclusion
In just a few steps, you can create and run a blazing-fast API using Bun. Whether you’re building a small project or scaling up, Bun’s speed and simplicity make it a great choice for modern development.

What do you think about Bun for API development? Share your thoughts in the comments below!

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