Does anyone know of a platform similar to Codeforces that can be used to create and run head-to-head games? It doesn't necessarily have to be a public website already on the internet; I'm willing to host it myself if necessary.

I'm imagining a platform that would have a system similar to Polygon where you can write an arbiter program that handles a head-to-head matchup between two contestants' programs. For example, let's say I'm running a rock-paper-scissors tournament. I'd write an arbiter program that reads in the two players' moves and returns the result of the game. Then contestants can submit their code in any supported language and the new submission will be run against all other participants' code.

Such a system probably isn't scalable if running every participant's program against every other participant's program is the goal, but that's fine. The use case I'm thinking of will almost certainly be around 25 people at most.

I've seen some systems somewhat similar to what I'm thinking of. MIT Battlecode comes to mind, but that's a highly specialized framework that only runs Java and has to deal with the game-specific bytecode requirements. I remember CMU's CMIMC's AI round had some head-to-head games, but I don't know if their infrastructure is available anywhere or how generalized it is.

Does anyone know of any open-source or otherwise public platforms/frameworks that can run head-to-head games? If you have expertise in this area, how difficult do you think it would be to build this, using preexisting frameworks such as CMS?