Hacker News Reader

The SCI/babashka clojure interpreter might be a good fit, if you're ok with a lisp.

It's mature and fully sandboxed.

I've wondered the same. There's https://jsonlogic.com/ but that seems like a data interchange format for logic, not something an end user or developer would write themselves.

If Scheme is something you enjoy, BiwaScheme's interpreter can be instantiated from within Javascript and can be used to evaluate Scheme code.

https://www.biwascheme.org/

Lua is usually the embedded language of choice. If you are focused on security, you could check out the Roblox fork, Luau (https://github.com/Roblox/luau) where the creators took extra care to lock down the language on what scripts could do.