Progressive Web Apps – or PWAs – are websites that you can run as apps on your computer, phone and tablet. They look and work exactly like a normal app, but there’s nothing to install – they run in their own browser-like window. Crucially, they’re not dependent on an internet connection, so they work offline too.
What’s the benefit?
PWAs are potentially safer than normal apps and programs because they don’t need to be installed on your device – thereby eradicating the risk of accidentally downloading malware. They also take up less storage space, because most of the app’s data is stored on a server rather than on your PC, phone or tablet. You never need to manually update a PWA – this is done automatically by the app’s developer. And they always work the same way, regardless of the operating system or type of device you’re using. So, you could use the same apps on your Android phone, Windows PC, iPad, or any other device that supports them.
How do they work?
The idea behind web apps isn’t new. Apple’s iPhone used them extensively when it first launched. The ‘progressive’ part refers to newer web technologies they use to deliver a smooth, safe, more app-like experience. The three main technologies involved are Cache API, Service Workers (which caches data to allow the apps to work offline) and Web App Manifest (which stores other data about the app, such as its settings). HTTPS encryption, meanwhile, ensures that connections can’t be intercepted.
Offline Wikipedia is one of the PWAs you can now use
In practice, when you use a PWA, you shouldn’t notice any difference compared with a normal app. You launch it by clicking or tapping a shortcut on your home screen or PC desktop. It then runs in its own window, and works as if it were installed on your device, with no delay, even if you have a weak internet connection (or if you’re offline). PWAs can provide notifications and carry out other background tasks, just like standard apps currently do.
What devices can I use them on?
You can already run PWAs on many current Android devices. Try them by going to pwa.rocks via Chrome on an Android phone or tablet and tapping one of the PWAs featured there, such as Offline Wikipedia, Flipboard and the mouth-watering Progressive Beer («the ultimate guide to beer all around the world»).
Once the web page loads, tap the menu button (three dots), select ‘Add to Home screen’, then tap Add in the message that pops up – you should now find a shortcut to the PWA version of the site on your Home screen.
What about on my computer?
Not yet, but you shouldn’t have long to wait. Microsoft believes that «PWAs are key to the web’s future», announcing last month (www.snipca.com/27088) that you’ll soon be able to run them in Windows 10 – available via the Windows Store. This may arrive as part of the Spring Creators Update, due in a few weeks. Apple is lagging a bit behind, though it recently added to its Safari browser support for some of the web technologies required to run PWAs. Many experts took this as a sign that the company is working on iPad and iPhone support too.