The app itself (iOS and Android!) is Walk for a Dog: "Walk for a Dog, a smartphone app that donates money to an animal shelter of your choosing every time you walk your dog. According to Walk for a Dog's parent organization, WoofTrax, donations are funded via sponsorship deals and advertising, and generally vary from 11 to 25 cents per mile, depending on the number of people who have signed up to walk in benefit of a particular animal organization."
Product Hunt Regular