Progressive Web Apps (PWAs) are web applications that provide a user experience similar to native mobile apps. They are built using standard web technologies like HTML, CSS, and JavaScript, allowing them to work on any device with a web browser. PWAs can be installed on a user's device and accessed offline, making them convenient and efficient. One of the key features of PWAs is their ability to send push notifications, keeping users engaged even when the app is not open. They also load quickly and can be added to the home screen, providing easy access without going through an app store.