I've been meaning to add this live cljs experience to http://hiccup.space A site to show how easy hiccup is to use.

Sadly not having paredit (or parinfer) support hurts the experience, so that's 2 features to add now!

If you use codemirror for the editing portion, you can use https://github.com/achengs/subpar to provide a subset of paredit in the browser.

Is there a parinfer package for emacs ?

Not that I know of, but adjust-parens is similar

Check the parinfer site, I'm pretty sure the implementation there runs on CodeMirror so it should be easy to get on your site if that's what you're using.

IIRC pareninfer is written in cljs, so porting it shouldn't be too hard.

If you want to build a REPL in the browser I'd highly recommend checking out replumb

https://github.com/ScalaConsultants/replumb

Even after finishing the readme I'm not clear on what exactly this does. At the very least it looks useful for working around the macros problem[1]. Mind explaining what mileage you got out of it?

[1]: http://blog.fikesfarm.com/posts/2015-09-07-messing-with-macr...