SWC is a tool that I see mentioned more and more.

It takes any JavaScript or TypeScript code and outputs JavaScript that works also on older browser, as well as (of course) modern browsers.

In short it’s the new Babel.

But faster.

They say 20x+ faster.

As a “normal dev”, you’re not going to use it yourself.

But it’s used by other tools.

We’re seeing an incremental focus on speed everywhere these days. Mostly because tools are rewritten in more optimized system languages like Rust instead of less optimized languages like JavaScript, which is more optimal for other use cases.

Vite 4, released in December 2022, now has support for SWC instead of Babel. Which in turn makes it faster.

It’s used by Turbopack, which is the Vercel-made JavaScript/TypeScript bundler/build system, alternative to Vite and Webpack.