The main feature of a progressive web application (PWA) is its ability to deliver a native app-like experience through a browser. PWAs combine the best features of web and mobile applications, offering offline functionality, push notifications, and fast loading times due to caching. They are built using standard web technologies like HTML, CSS, and JavaScript, which ensures compatibility across devices and platforms. This versatility allows users to access PWAs directly via URLs without needing installation from an app store. Consequently, PWAs enhance user engagement and satisfaction, making them a popular choice for businesses aiming to reach a broader audience efficiently.