The Squirrel Restaurant POS system provides core support for credit/gift/debit card payment methods. They also provide the infrastructure to allow some customization of this support and require customization for communicating with the Payment Processor.

Squirrel is a client-server system. The Squirrel POS workstation is a Java application which usually runs on a diskless POS workstation with a touch screen and magnetic card reader (as well as peripheral interfaces for printers, etc). The POS workstation itself usually runs an embedded Linux OS which is booted over the network. It is possible to run the Squirrel POS workstation application under Linux or Windows, though this is rare.