Show HN: I made an in-browser code editor with code replay and REPL

I made a Logicboard.com — A collaborative code editor with code-replay feature.

Code-replay lets you run the coding session like a movie, I wrote a blog post on how I implemented this: https://logicboard.com/blog/code-replay

You can try out the demo here: https://logicboard.com/demo/:replay

And play around with the code editor here: https://logicboard.com/demo/

Logicboard also has an REPL shell, just type "start()" and hit enter in the output area.