Bun is the new Javascript Runtime built from scratch to serve the modern Javascript ecosystem.
But do we really need more Javascript tools?
Well, the Javascript Space is completely different from 15 years ago when NodeJS was first released.
- Yearly new releases of
ECMAScript. - Typescript becoming the norm because of the enhanced Developer experience.
- Use of JSX in almost every development framework.
These have forced the Javascript runtimes to become lighter and faster.
Deno - Modern runtime that becamse Jurasic
A little bit ago, we got Deno. While it is just No-De reversed as De-No, it does more than that.
It's features are listed on their website :
But, Deno essentially failed, because :
Deno only really sported "minor features" from a users perspective. It had a cleaner codebase, used up-to-date best-practices, and had better security, but those things are really only "features" to a user, not a product in themselves.
The Technology Behind Bun
Bun is a Javascript Runtime. But what does it mean actually?
It starts with an Engine - The Component of a runtime that runs the Javascript code.
We all know V8, the JS Engine behind Chrome and NodeJS.
But Bun uses something different - JavascriptCore.
Javascript Core is a Performance🚀 focused solution built by Apple 🍎 for the Safari Browser
The JS engine cannot work on it's own. So it combines with external APIs and message Queues and the infamous Event loop to create a Javascript Runtime.
In Bun, this is implemented from scratch using Zig which is a low-level general purpose language like C or Rust for building fast applications.
The above implementation provides better performance and memory management during Start and Runtimes, combined with the promise of mind-blowing speed, you have a real competitor of NodeJS.
Features of Bun
Bun has a lot of great features that makes it worthy.
1. Support for NodeJS packages 🎯
Bun is like a Drop-In replacement for NodeJS thanks to the native implementation of 100s of Node modules
Bun also uses the package.json file for dependencies, so less learning curve from NodeJS and bun install is really fast 👇
2. Built in Typescript Support and it's fast ⚡
Before the dawn of Bun, running typescript was tedious and slow. Bun comes with built in support for running Typescript in your projects and makes it faster.
3. Support for both CommonJS and ESModules(MyFavorite) 🎉
Remember those days where you had to convert your project from the old require syntax to import syntax? Some libraries still not support the import syntax perfectly with Typescript.
This all goes away with Bun. You can write either or both.
4. Built-In Testing Support 💡
You love the Test driven development? Or are you just starting with it? It doesn't matter. Because you do not have to go and learn a new testing framework to do the job.
Bun comes with built-in testing support, and so it is much faster from the other ones out there.
Enough talk, let's see some examples of using Bun 📌
Installing Bun
Installing Bun is as simple as below :
curl -fsSL https://bun.sh/install | bash
Setting up a Server
Ready to develop your own service? Create a new file : server.ts and add the following code :
Start the server
Now to start listening to requests, run the following command(no intermediate step of converting to .js separately) :
bun index.tsx
React Components with Bun
Bun supports .jsx and .tsx files out of the box. Bun's internal transpiler converts JSX syntax into vanilla JavaScript before execution.
It also works with the above React component.
With the above features and many more, Bun is ready to become the new norm in the Javascript runtime market.
Do you want to use Bun in your projects? Checkout their official website for Getting Started and installation guides here : Bun.js
Top comments (18)
The thrill of diving into new technology is like an adrenaline shot for any software engineer. As someone who enjoys tinkering with new tools, I'm always eager to explore the latest and greatest. But wearing the hat of a technical lead and a university professor in computer science with a 21-year career in software development changes the game. It's like having an internal debate between an angel and a devil: Should you adopt this promising new technology or be cautious?
Early adopters, especially in the open-source community, are crucial catalysts for innovation. They help technologies evolve through their valuable contributions. But when it comes to corporate adoption, we must shift gears. Corporations need mature, battle-tested solutions.
Take Node.js, for example. It's been a 14-year journey for it to reach its current mature state. Deno, around since 2018, is still considered somewhat obscure. Bun is an even newer kid on the block and far from production-ready. Its potential may be promising, but resilience, sustained development, and vision are key for its long-term viability.
To carve out a niche in the corporate world, Bun needs more than just promising features. It needs a vibrant community, widespread industry adoption, and enough momentum to host events and generate buzz. Only then could we even start to think of it as a serious contender to Node.js.
Another challenge is balancing performance with developer-friendliness. As you build abstractions to make life easier for developers, you risk diluting the tool's performance and efficiency. Maintaining that balance while sticking to the initial vision is no small feat.
The choice of the Zig programming language for Bun is another intriguing design decision. Who's going to learn Zig just to contribute? Why not go for something more commonly adopted, like Rust? It raises questions about the future talent pool and whether this choice aligns with corporate considerations.
Even as I wish Bun all the success, only time will tell if it will stand the test of time, especially given that other solutions like Just.js, Cobra, and Hermes already outperform it.
So while the pace of technological evolution is exhilarating, it also makes it incredibly challenging to maintain consistent development and vision for new products. Before Bun—or any emerging technology—becomes viable for corporate adoption, it must check numerous boxes, from community support to feature stability. As much as we'd like to dive head-first into every new technology, the devil is in the details, and those details demand a discerning eye.
I saw that Zig has been around for no less than 7 years - and I've never ever heard of it, that's saying something I think ...
P.S. what Bun got on the alternatives that you mentioned (Hermes etc) - a cool name, arguably the coolest of the bun(ch) ! :-D
I agree that not all solutions that come can uproot NodeJs and none of them should.
But Node could really use some speed upgrades during these times and yes other solutions also do outperform in speed, but Bun comes with a lot of features that need to be in a runtime.
So I wish that Bun is developed into a full fledged runtime and we could have SOMETHING THAT REACT AND ANGULAR HAVE, separate usecases but demand for both
Great points, tend to agree with you. In regards node speed upgrades, here is the repo where discussion and implementation about performance in Node happens: github.com/nodejs/performance
Just try the 1.0 and for me it's promising but lack several features :
I'm sure in few months/years it will be a killer app but it's still too early.
That is true.
Bun is already a great product, but has room for so many improvements.
Linter and code style would be a good plus
Thanks for sharing, it's worth giving a try
Yes it sure it
Hey Vinit! Nice article :)
Thanks Nathan 😄
Thanks for the thoughtful review, Vinit. 🎉
Thanks Randell, happy to help
I've read about Bun and it seems promising. It's definitely faster than Node.js, and it's written in Zig, which is a plus However, I'm a little bit concerned about its lack of maturity. It's still under development, and it's not as widely supported as Node.js. I'm also not sure how well it will work with existing Node.js modules.
According to me, here are a few things that Bun needs to improve:
Stability: Bun is still under active development, so there may be bugs and performance issues that have not yet been identified. Bun needs to be more stable before it can be widely adopted.
Compatibility: Bun is not fully compatible with all Node.js modules. Bun needs to be more compatible with existing Node.js modules so that developers can easily switch to Bun.
Documentation: The documentation for Bun is still limited. Bun needs to have more comprehensive documentation so that developers can easily learn how to use it.
Community: Bun is a new project, so there is not yet a large community of users and developers to help out if you run into problems. Bun needs to build a larger community so that developers can get help and support when they need it.
Really insightful breakdown! It’s true—the JavaScript space is vastly different now than it was when Node.js was released. Bun’s rise is a testament to this shift. It’s built with modern dev needs in mind, from built-in TypeScript and JSX support to its blazing-fast package manager. Since Bun uses JavaScriptCore (instead of V8) and is written in Zig, its focus on performance is clear. You’re not just looking at speed but also reduced complexity—built-in tools for bundling, testing, and running scripts eliminate the need for extra dependencies.
Deno brought some modern security and coding best practices, but as you pointed out, Bun’s “all-in-one” approach is unique. By incorporating essential tools that developers usually add on top of Node.js, Bun feels like a natural step forward in streamlining workflows. And thanks to its compatibility with Node APIs and npm packages, it’s easier to adopt without a steep learning curve.
This article from one of my colleagues, Matheus Berkenbrock, jump into these differences in more detail and weighs Bun’s advantages for developers looking to simplify and speed up their setups. If you're interested, here's the link: scalablepath.com/nodejs/bun-node-a...
Looking forward to seeing how this space continues to evolve!
Very nice! I was able to run it on windows through wsl.
Amazing 👌
Thanks Rizmy 🚀