Haz is a social second-hand app called "Haz: See what your friends own" designed for iPhone users. It provides a unique platform where users can track what their friends are buying and selling online. The app offers features such as customizable sharing settings for notifications, leaderboards to rank users based on shopping habits, and automatic creation of digital item listings from receipts.

With Haz, users can easily manage their belongings, monitor real-time resale values of items, and even sell unwanted items effortlessly. The app ensures transparency by linking items to original purchase receipts and requiring video listings from sellers for buyer confirmation. Haz aims to revolutionize the social second-hand market experience by providing comprehensive tracking and control features for users.