This app offers a web-wide multi-store checkout system. Keep allows you to enter your financial details into the system one time only. In that sense, it works on a similar principle to PayPal. Instead of having to enter your details into each website you wish to buy from, you enter it into the Keep system and then checkout your purchases through Keep. This allows you to buy from different stores at the same time with various items in your shopping basket when you send payment through.