Is there any way to tune down mob spawning?

I’m running a modded survival server for me and my friends but even on game difficulty easy loads of mobs spawn. This is seriously getting annoying because we can’t even walk out of our house without getting killed by a skeleton or having our terrain ruined by creepers.

Thanks

Dont quote me on this (unless its right), but I believe it is in the following folder.

configuration/sponge

And its on a per world basis