The purpose of a fitness tracker is to monitor and facilitate various aspects of physical activity and health. These devices can track metrics such as steps, heart rate, calories burned, and sleep patterns. By providing real-time data, fitness trackers motivate users to set and achieve fitness goals. Many also offer reminders to move and engage in physical activity, promoting a more active lifestyle. By analyzing the collected data, users can better understand their habits and make informed adjustments for improved health and wellness.