Honest question, but this seems like an expensive project to host given the number of tokens per second. How is this being paid for?

Good question! The player rooms have a rate limit per day. And as for the main table, it's actually a replay of hands I recorded the LLMs playing against each other over an extended time which eventually loops.

Looks like this was cleverly designed to prevent costs blowing up. There's one game shared for everyone on the main page, and up to 100 private games per day.