A sleep app is a smartphone or wearable device application designed to monitor, analyze, and improve sleep. Over the past decade, sleep apps have become increasingly popular as accessible tools for those looking to better understand their sleep patterns and address common sleep problems. Sleep apps vary widely in their features and approach. Monitoring apps use the phone’s microphone and accelerometer — or data from a paired wearable device such as a smartwatch — to track movement and sounds during sleep, estimating sleep duration, sleep stages, and sleep quality. They typically present this data in easy-to-read graphs and scores, helping users identify patterns and trends over time. Many sleep apps also offer active sleep improvement features. These may include guided sleep meditations, breathing exercises, sleep stories, relaxation sounds and music, white noise and nature soundscapes, and customizable sleep schedules. Some apps incorporate principles from cognitive behavioral therapy for insomnia (CBT-I) and provide structured programs for addressing chronic sleep difficulties. Smart alarm features, which aim to wake the user during a lighter sleep phase to reduce sleep inertia, are another common function. Sleep diary tools allow users to log lifestyle factors such as caffeine intake, exercise, and stress to identify what affects their sleep. Popular sleep apps include Sleep Cycle, Calm, Headspace, Pzizz, and Pillow, among many others. While sleep apps can be useful tools for general sleep awareness and relaxation support, they are not a substitute for clinical diagnosis and treatment of sleep disorders. If you have persistent sleep problems, consulting a healthcare professional remains the most important step.