Looks like deposits are handled manually.... Hmm. Yep, they definitely are handled manually. Gonna be fun times for OP. I would be wary of using this game.
OP: If it's not manual (99.9% sure it is), what IPN/API do you use to handle deposits and payouts of that many coins?
Deposits and Withdrawals are fully automated. We have some problems with our automat, but we fix it and now deposits works fine.