Simply put, a Progressive Web App(PWA) is a website which uses an app shell to provide app-style gestures and navigation making it work like a native app. There is no need to download it from an app store because it is hosted online and runs, self-contained, right in a web browser. Web Apps have advantages over native apps because it is able to load instantly even in slow connectivity situations. With the help of pre-caching, the app stays up to date at all times, displaying the most recent version upon launching.

An app developer may build an app for IOS, for example, to extend the app to other platforms, that developer would have to rewrite the code and do full app development for those platforms, debugging, submitting it on the different app stores etc.

This makes it more expensive and time-consuming. This is where PWAs fit in perfectly. They are built on one platform (the web) and serve or are accessible to any other platform without much tweaking needed since it is accessed only with a web browser. This makes app development and maintenance way less expensive and resources consuming. Technologies used in the site such as persuasive technology can be improved on without much hassle and the need for deploying app updates to all the mobile platforms involved. Since these apps are essentially websites, Google will be able to index its pages giving more chances of the app to be discovered

Windows 10

The Windows 10 eco-system is built around this premise.

Though app development for windows is much more demanding than Android or IOS. A decent phone os may consist somewhere of around 50-100 thousand Lines Of Code whereas for a complex os like windows 10 may have up to 50m lines of code, same proportions with apps on these platforms

Microsoft has really simplified its ecosystem to harness the advantages of PWAs.

The amount of work needed to create an app for the ecosystem is done once and can be applied to any Microsoft system like full Windows 10, Windows 10 mobile, windows virtual reality headsets even the Xbox One X announced at E3 as Thom peart reports. One application package for all Windows devices. I like to refer to these apps as intelligent apps because they are built to identify the system it's running on and adapt to the different hardware like display size.

The future

PWAs generally means bad news for platforms that are struggling to get popularity and even worse for new platforms. A report by Rita Guerra shows how the windows 10 mobile struggled to get developers on their platform. Apps stores are being discontinued because more and more developers are leaving and as Progressive Web Apps continues to grow in popularity, it renders native apps obsolete and hence their app stores. The Chrome web store and even Windows are having a hard time getting developers onboard their platforms for this reason.

Google Chrome and other browsers are available on multiple platforms like Windows, Mac, Linux, or Chrome OS IOS, Android etc. While Google is planning on bringing support for installation of Progressive Web Apps in mid-2018 for desktop, Chrome for Android is already able to install these apps. Progressive Web Apps is the direction app development is taking for the future.