I use some CLOS, but most of it is plain old Lisp trying to avoid side-effects. Deploying is just dumping an SBCL core with the right functionality in it. It lives in a private server inside a VPN, listening to a port. Nothing fancy, really. I did consider at some point serving the web with Lisp as well (https://edicl.github.io/hunchentoot/, because I trust Edi Weitz's code) but I ended up doing it in python.