All processing fees are charged to the tenant.
Tenants are charged $1.00 per ACH/bank/eCheck Transaction (recommended)
Tenants are charged 3.1% + $0.30 per US Card Transaction
Debit cards are considered a credit card and charged the same rate
You can also turn off card payments and accept ACH-Only (Read: Accept ACH-Only)
You can also modify the "Convenience Fees" option in settings if you want to cover either fee yourself. (Read: How to Pay the Fee For Your Tenants)