Setting Up an HTTP Server with Bun

09 January, 2024


What is Bun?

Bun is a new Javascript runtime that focuses on simplicity, performance and developer experience. It has been built with the lessons from NodeJs in mind to minimise some of the common pitfalls of a Javascript runtime.
Bun has been built to minimise and abstract away a lot of the complexities from NodeJs to allow developers to focus on clean, maintainable, performant code.

Getting Started

  • Install Bun for your OS as per the official Bun instructions
  • Create a folder for your Bun project code files to live.
  • In a terminal for the new folder run bun init to set up the Bun project
  • Create an app.ts file in the folder

Creating the Bun Application

Open the app.ts file in your code editor of choice and add the following code:

const server = Bun.serve({ port: 3000, fetch(request) { return new Response("Welcome to Bun!"); }, }); console.log(`Listening on ${server.url}`);

If you are familiar with the Express framework, this should look very familiar.

This code snippet creates the bun app, sets up a basic response for the server, configures a port and starts the server.

Running the Server

Back in your terminal with the project folder open, run bun app.ts

In a browser, you can now navigate to http://localhost:3000 which will present you with the text 'Welcome to Bun!'


As shown above, the Bun framework provides a simple and effective way to create an HTTP server or API. This allows you to focus on writing clean, maintainable and performant code.

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