PiPiMy is a mobile e-commerce platform that lets users buy and sell things easily with their smartphone. You can list an item using your phone, and add photos and a short video clip to your product. The small startup formed in 2015.
I was one of the first members of the team, and the primary developer for the PiPiMy iOS app, from early development stage to the publishing the first version on the App Store (2015-16). The app is written in Objective-C and has a fairly extensive set of features.