[t0astbread]

Sibling comments mentioned some approaches already but just FYI, Hacker News is built on Arc, a custom-made Lisp dialect: https://en.wikipedia.org/wiki/Arc_(programming_language)

[neoplatonian]

I thought Arc was only for backend? Or does it render HTML as well?

[t0astbread]

I think the backend directly emits HTML. Some JS (without libraries if I'm not mistaken) is used on the client side for things like voting. I don't know how it does persistence or what its infrastructure looks like.