- Prybar: Universal REPL interface https://github.com/replit/prybar
- Polygott: Universal docker image for all languages (we support) https://github.com/replit/polygott
Between these three you'd be able to add your favorite language to Repl.it (patches welcome). We have a write up on how to do that using elisp as an example: https://repl.it/site/blog/elisp