Progressive Web Apps (PWAs) are regular mobile and desktop web applications that are accessible in any web browser. In browsers that support new open web standards - including Samsung Internet for Android - they can provide additional capabilities including offline support.
Having the ability to load from a cache means that PWAs can have great performance benefits, providing almost-instant loading times for return visitors.
You do not necessarily need to build a new PWA from scratch. The features can be added to your existing web properties using Progressive Enhancement.
Service Workers
The most important web feature that enables PWAs is the Service Worker. A Service Worker is like a network proxy that runs in your browser. It can intercept requests to the network and depending on what you program it to do, it could return a response from a cache. This is what allows web apps to work offline.
If you have heard of AppCache, an earlier browser feature that also promised offline web apps, you can think of Service Workers as replacing and surpassing AppCache. AppCache had widely reported issues and limitations. Service Workers are designed to be much more programmable and powerful.
Service Workers are restricted to secure contexts, so (except for local development) you will need to use HTTPS. They have been supported in Samsung Internet for Android since v4.
Web App Manifest
Web App Manifests provide a standard way to describe how your web app should appear on the home screen and how it should launch. It consists of a simple JSON file that you reference via a meta tag. Here is an example from Diego Gonzalez’s Bubble web app.
In Samsung Internet for Android, the user can choose ‘Add shortcut on Home screen’ from the menu. If your manifest declares them appropriately, your chosen icon will appear on the home screen along with your chosen short name.
If Samsung Internet detects that your website is a PWA, it will dynamically display a plus icon in the URL bar, making it even easier to add it to your home screen. For more information, see Ambient Badging and Adding web apps to your homescreen.
In the same way, in Samsung Internet running on Samsung DeX, web apps can be added to the desktop.
If you set the ‘display’ property to ‘standalone’, when the user taps on the icon, the web app will launch without the browser frame and URL bar.
Web App Manifest support arrived in Samsung Internet v4.
Push Notifications
Push notifications are not a requirement for being recognised as a Progressive Web App. However, they are another example of a native app feature coming to the web. When used carefully they can prove useful for re-engagement.
Push notifications rely on service worker support, plus two further APIs: the Notification API and the Push API. The Notification API is used to display notifications. The Push API is used in a service worker to handle the push messages from the server. Because Service Workers are not tied to the lifetime of a browser tab, they can respond to push messages even when your web application is not currently open.
Samsung Internet for Android has supported the Notification API and Push API since v4. Note: The “Web Notifications” API listed here on caniuse.com is marked as unsupported by Samsung Internet and Chrome for Android, but this refers to an earlier specification. Notifications can be triggered via push messages in the service worker context.
Further Information
- Progressive Web Apps - MDN Docs
- A beginner’s guide to making Progressive Web Apps by Uve Tusliani
- A beginner’s guide to Service Workers by Uve Tusliani
- The Building Blocks of Progressive Web Apps by Ada Rose Edwards
- Here’s what you get for free with a Progressive Web App by Peter O’Shaughnessy
- Progressive Web Apps training materials in collaboration with Google
