An Ant in a World of Elephants - Why You Should Take a Closer Look at the Ant Runtime

Imagine you're packaging a Docker container for a simple cloud function. You write ten lines of JavaScript code and end up with an image that's hundreds of megabytes. Most of that weight is Node.js. We've gotten used to this "infrastructure tax," but a developer going by theMackabu decided it's time for a change. Their project Ant is an attempt to create a JavaScript runtime that weighs just 8 MB but knows how to fly.

What It Is and Why You Need It

Ant is a lightweight JavaScript runtime written from scratch in C. The author didn't use an existing engine like V8 (as in Node.js or Deno) or JavaScriptCore (as in Bun). Instead, they wrote their own engine called Ant Silver.

Why bother when giants already exist? The answer is in the numbers. Node.js "out of the box" weighs around 120 MB. Ant takes up 8 MB in a standard build and can shrink to 4 MB if compiled with size optimization. This makes it an ideal candidate for edge computing, embedded systems, and CLI utilities where every megabyte and every millisecond counts.

Cold Start That Impresses

One of the main pain points in serverless architecture is "cold start" — the time a platform needs to spin up the runtime and begin executing your code. While Node.js takes roughly 30 ms to initialize, Ant handles it in just 5 ms.

The project's benchmarks use Hono — a popular framework for building APIs. Ant loads Hono, registers routes, and exits twice as fast as Bun and five times faster than Node.js. Of course, this is a synthetic startup-and-exit test, but it clearly demonstrates how much less overhead the runtime has during initialization.

Technical Internals

Building a custom JS engine solo sounds insane, but there are some clever solutions here. The Ant Silver engine uses a JIT compiler based on MIR. This lightweight backend enables JavaScript code to execute at speeds approaching compiled languages while not requiring gigabytes of RAM for the optimizer to function.

The project targets the WinterTC standard (Minimum Common API). This is an attempt to make code written for one server-side JS environment run unchanged in another. Currently, Ant fully passes compatibility tests for ES1–ES6 and subsequent specifications (15,011 tests out of 15,011). However, in more comprehensive tests test262 coverage is currently around 64%. The author openly acknowledges that work is ongoing, with focus on the features developers actually need.

Where It Can Be Used

I see several scenarios where Ant could already make an impact:

1. Micro-CLI tools. If you're writing a small utility for colleagues that needs to be quickly downloaded and run, a 4 MB binary looks much more appealing than requiring Node.js installation.
2. Edge Computing. In distributed networks where code runs as close to the user as possible, the small footprint and fast startup directly impact latency.
3. IoT and embedded systems. Where memory resources are constrained, regular Node.js simply won't fit, while Ant will feel quite at home.

How to Try It

Installation is standard for tools like this:

curl -fsSL https://antjs.org/install | bash

If you want to look under the hood and build it yourself, you'll need a C compiler. The project is actively developing, and the author maintains an interesting blog about implementation internals, explaining how the ant manages to carry 50 times its own weight.

Should You Switch to It Today?

Let's be honest: Ant is still an ambitious experiment. If your work depends on specific Node.js native modules or the vast NPM ecosystem that relies on V8 internals, you'll run into problems.

However, if you need a minimalist tool for running JS in specific conditions, or you're simply tired of the heaviness of modern solutions — give this repository a star. This is a rare example of one person challenging the architectural bloat of the industry. Even if Ant doesn't replace Node.js, it will definitely make other runtime developers think about optimization.