In the previous video, you learned that progressive web apps provide a native

app experience using modern web technologies.

Fundamentally, progressive web apps are not much different from regular websites

that are built with HTML, CSS, and JavaScript, and displayed in the browser.

What makes progressive web apps different from normal websites

are ten distinct characteristics.

These app-like characteristics,

defined by developers at Google, when fulfilled, will boost the experience of

your web app by providing most of the capabilities of native apps.

First up, being progressive means that a web app must work for

every user on all devices, regardless of the browser being used.

Progressive enhancement lies at the heart of progressive web app development.

The native app experience should be available to users with browsers

that support the technologies for progressive web apps and

take advantage of any features available on the user's device and

browser, but still deliver a standard experience to users on older browsers.

A progressive web app is also responsive, meaning it should fit any form factor,

a desktop, mobile, or tablet device.

Like you saw in the Flipkart Light and Flipboard apps, progressive web apps

provide a fully immersive experience, so they should fill the screen of a device

perfectly, using the principles and techniques of responsive web design.

Now one important characteristic is connectivity independence,

progressive web apps should work in areas of low connectivity or, like I showed you

on Flipkart Light, even when there is no Internet connection available.

A user can launch the app and

still display useful information no matter the connection, this is

accomplished by enhancing your app with a browser feature called service workers.

The browser runs service worker scripts in the background

to load your content almost instantly in an online connection and

still display content so that your app works offline or in low-quality networks.

You'll learn about service workers in the next video.

A progressive web app needs to feel like an app to the user,

with app-like interactions navigation and

minimal page refreshes, the app should respond quickly to user interactions.

When there's motion on the screen, like scrolling, transitions,

or animations, users shouldn't experience any stuttering or

choppiness, the experience should be silky smooth.

Earlier, you saw how launching an app from a home screen icon

displays the app full screen, without the browser Chrome, meaning no URL bar or

the forward and back buttons usually provided by the browser.

The app is built using an architectural model called Application Shell,

which I'll cover in a later video.

Next, a progressive web app should always be up to date, using service worker

updates when new content is published and the user is connected to the Internet,

that content should be made available in the app.

An app should be safe, so every progressive web app has to be served

through an HTTPS connection to prevent snooping and

ensure content hasn't been tampered with.

You see, progressive web apps work with native APIs, service workers, and

technologies that deal with sensitive data, so

this should be handled with caution.

Now, a free and easy way to run your app in a secure environment

is via GitHub pages, which can host directly over HTTPS.

Next, a progressive web app is on the web, so users should be able to discover

the app in search engines, this is one of the biggest advantages over native apps,

native apps lack the searchability of progressive web apps.

And later we'll cover the features that make progressive web apps

easily searchable in search engines.

Progressive web apps make re-engagement easy

through features like push notifications, just like on native apps.

Using service workers and the push API, progressive web apps can deliver

asynchronous notifications and updates to users that opt in,

which results in better engagement with timely new content.

Now, a progressive web app can be installed on the device's home screen,

making it readily available to users, so

when they launch it, it will feel just like any other app on their device, and

when in use, it even appears as a top level app in a device's tasks switcher.

Finally, progressive web apps are easily shared via URLs,

users simply click a link to access the content they're looking for.

There is zero friction, so

there's no complex installation and anyone with a web browser has access to the app.

So with the right set of capabilities in a browser, a progressive web app can be

as performant, reliable and as engaging as a native app.

Up next, you'll learn more about the technologies that go into

progressive web app development.