Square - Square helps millions of sellers run their business-from secure credit card processing to point of sale solutions. Get paid faster with Square. Sign up today!
jtrac - JTrac is an open source and highly customizable issue-tracking web-application written in Java.
Lightspeed - retail and restaurant point-of-sale, ecommerce, and omnichannel solution
16bugs - 16bugs is an all-in-one bug tracking software that makes it easier for you to manage all sorts of bugs in performance with the simple interface; ultimately, you will be more productive for sure.
QuickBooksPOS - QuickBooksPOS offer POS system software for small businesses.
Bugify - Bugify is a simple PHP issue tracker, designed to offer powerful bug tracking capabilities in an easy to use system.