I just did a little benchmarking of my own. Here's how the three perform on 100 compilations of an ES5 version of Parser.js from the webpack source code: s

I just did a little benchmarking of my own. Here's how the three perform on 100 compilations of an ES5 version of Parser.js from the webpack source code: sucrase: 900.720ms swc: 4514.190ms babel: 16126.752ms Sucrase had the jsx and imports transforms enabled, swc had all transforms enabled (they're not configurable), and Babel had @babel/preset-env enabled. So I'm a little skeptical of swc's 20x speedup claim, but certainly depends on a lot of details.