I work as an engineer at https://datacamp.com, and we run the code directly on a server, but I've always thought it would be interesting to try building interactive programming exercises with Skulpt.
Plug: you could easily prototype this with Trinket embeds. Add #!/bin/python3 to the top of our Python (Skulpt) trinkets to get strict Py3 mode. Add data files via the + button (no directory support, so treat them as all in the local directory). Use the Share menu to get embed code. Paste. You've got your first interactive lesson. If your users like it, you can then decide whether and how to build skulpt in to the site.