PWA

A Progressive Web App is a web site or web app that can provide a more app-like experience while keeping the reach of the web.

What you will learn

What a PWA is and what it is not
How a manifest and a service worker contribute
Why HTTPS, accessibility, and ordinary web quality come first

The three ideas

Web app manifest: A JSON file describes the app name, icons, colors, and how it should open.
Service worker: A background script can handle selected requests and enable offline or install-related behavior.
Responsive web page: The foundation is still a fast, accessible page that works without installation.

Start small

Make the page responsive and keyboard-friendly.
Serve it over HTTPS.
Add a valid manifest with suitable icons.
Add a service worker only when you can explain its cache and update strategy.

Do not promise offline support until you have tested stale content, failed requests, and an updated release.