Does everything need a "session"? Is it possible to have fully static games/exports?
Theoretically you could do this all client side too, but that would remove the magic of every game getting multiplayer for free
fun
You'd still get multiplayer "for free", but it could be turned on and off. You could do it with zero code change for the actual games, they don't have to know.
It seems some of the games could do with a singleplayer mode that doesn't depend on the backend having free slots.
Just an idea from a fellow web games person!
Why reach for a server unless you truly need one! My multiplayer mode is p2p planned