SWC

SWC does the same work as Babel, 20-70x faster, because it's written in Rust instead of JavaScript. It replaces Babel for transpilation and Terser for minification.

Apache 2.0, used by Next.js, Deno, and Parcel. When Vercel adopted SWC as Next.js's default compiler, build times dropped dramatically for every Next.js project. That's the real-world validation.

Fully free. CLI tool and JavaScript API, no paid tier.

The catch: SWC's Babel plugin compatibility is incomplete. If your project relies on specific Babel plugins (especially ones that transform code in unusual ways), you might hit gaps. The bundler (swcpack) is still experimental. Most teams use SWC for transpilation only and pair it with a separate bundler. And when something goes wrong, debugging is harder than Babel because the actual processing happens in Rust, not JavaScript. For most projects the speed gain is worth it, but test your build thoroughly before migrating from Babel.