Ah interesting, I'll check it out. I figured this had to exist! It might be ideal --- I'm on a github-pages Jekyll site and I like how simple that is, but it means I can't do anything server-side at all, not even making custom Jekyll plugins.
How big does the resulting binary get?
edit: oh, looked at the demo on https://tikzjax-demo.glitch.me/ and it seems like it is just a couple MB. Not bad.