A: You can use any merchant services you like in conjunction with Point of Sale, but in order to obtain the required authorizations for credit card sales, you’ll need to manually enter the transaction information into your credit card terminal – an extra step that can introduce errors. The only current processor besides Intuit that works inside QuickBooks Point of Sale is MercuryPay. Learn More. And you can’t capture the authorization code in the sales record unless you enter it manually (except for Mercury). QuickBooks Point of Sale Merchant Service and MercuryPay are the only services that allow you to authorize credit card transactions directly from the actual sales record in the software. There’s no need to re-enter anything, no extra steps, and it can reduce errors.