What is PWA?

When Google came up with the PWA, it didn't have a precise definition. It is not a specific technology, but a combination of techniques to improve the user experience. Those technologies are Web App Manifest, Service Worker, Web Push, etc.

The main features of PWA are as follows.

• Reliability - instant loading, even in unstable or disconnected network environments.
• User experience - rapid response, with smooth transition animations and feedback on user actions
• Stickiness - like the Native App, can be added to the home screen and receive offline notifications.

PWA itself emphasizes Progressive (Progressive) in two perspectives.

1. PWA is still evolving;
2. PWA is downward-compatible and non-intrusive. It costs developers little to use the new features - developers can add it to the existing site progressively.

Google's "Progressive Web App Checklist" defines those minimum requirements for PWA.

• served over HTTPS.
• Pages should be responsive on desktop, tablet, and mobile devices
• All URLs have content to show in case of disconnection, not the default browser page
• requires Web App Manifest to be added to the desktop
• Faster page loading and shorter delay, even on 3G networks
• It displays correctly in all major browsers
• Smooth animation with immediate feedback
• Each page has its own URL

Features of PWA

A PWA combines the benefits of both the Web App and Native App and gives us the following features.

• Progressive - for all browsers, as it is developed with progressive enhancements in mind
• Connectivity agnostic - Ability to leverage Service Worker for offline or low network connectivity.
• Native experiences - on the App Shell model, they should have Native App interactions.
• Continued updates -- always up-to-date, no version or update issues.
• Security - Served over HTTPS
• Indexable - manifest files and Service Workers can be recognized and indexed by the search engine.
• Stickiness - By pushing offline notifications, etc., you can get users back to your app.
• Installable - users can easily add web apps to the home or desktop without going to an app store.
• Linkable - share contents through links without downloading and installing them.

More specifically, what is the advantage of PWA over the native app? Openness and index-ability. Users can hardly install a native app instantly and search across native apps seamlessly.

The table below shows the comparison between t raditional Web App, Native App, and PWA for each feature.

	Installable	Linkable	User experience	User stickiness
Traditional Web	❌	✅	❌	❌
Native App	✅	😐	✅️	✅
PWA	✅	✅	✅	✅