Rose connects to Square through their developer's APIs, which are essentially software connections allowing the two programs to talk to each other.
Rose is the only consignment software built with Square. This means you don't have to try to make Square do things it wasn't designed to do - track consignment. Your work/life balance is important, let Rose track your consignment sales so you can focus on your customers and your relationship with your consignors.
It also means you don't have to import and export data files like other programs who claim to work with Square's POS.