Aaptiv is a mobile application that provides audio-based fitness programs and workouts. It offers a range of guided audio classes led by certified trainers, covering various activities such as running, walking, cycling, strength training, yoga, and meditation. The service is designed to provide users with the flexibility to work out anytime and anywhere, with new classes added regularly. Features of Aaptiv include the ability to select workouts based on duration, type, and difficulty, personalized fitness plans, and access to a community of users for support and motivation.