Merchants should look for payment processors that are PCI compliant to ensure their encryption is secure. They should also consider the payment methods their customers use, as each payment gateway typically does not accept payments from every card issuer and payment processing portal. Stacking payment gateways, or using multiple payment gateways on your platform, can give customers more options for possible payments beyond credit card payments—not just multiple credit card issuers, but also options like PayPal, Venmo, and ApplePay.