A PWA is a web app that follows a set of design principles and standards that make it behave like a native app. A PWA is progressive, meaning it works for everyone, regardless of the browser or device they use. It is responsive, meaning it adapts to different screen sizes and orientations. It is connectivity-independent, meaning it can work offline or on low-quality networks, thanks to a service worker that caches the app's resources. It is app-like, meaning it has a user-friendly interface, a home screen icon, and a full-screen mode. It is fresh, meaning it always shows the latest content, thanks to the service worker that updates the app in the background. It is safe, meaning it uses HTTPS to ensure secure data transmission. It is discoverable, meaning it can be found by search engines and users, thanks to a web app manifest that describes the app's metadata. It is re-engageable, meaning it can send push notifications to users, thanks to the Push API and the Notification API. It is installable, meaning it can be added to the home screen or the app launcher, thanks to the web app manifest and the BeforeInstallPrompt event. And it is linkable, meaning it can be easily shared and accessed, without requiring complex installation or registration.