Progressive Web Apps (PWA): For which projects?

by | 7 Apr 2021 | Web Expertise

Progressive Web Apps (PWAs) were popular a few years ago. Supported by Google, this technology allows the creation of mobile services with features comparable to native applications, but accessible from a simple browser. 

Where are we today? What can PWAs really do? For which type of project is the choice of a PWA relevant?

Which technologies to develop a mobile project?

Today, to create a service accessible from mobile devices, you have a plethora of possibilities. Development costs and possibilities vary depending on the solution you choose: we offer a quick summary of the different technologies to start : responsive website, native or hybrid mobile application, and of course, this is the subject of this article, progressive web app (PWA).

- Responsive website

You can create a responsive website, that is to say, one that adapts to all screen sizes; today, there is even a tendency to think of sites primarily for mobile terminals (mobile first), since mobiles account for about 55% of global web traffic.

- Mobile application

A traditional responsive website is great for offering content that can be easily consulted in a mobile situation, but it offers far fewer possibilities than a mobile application. 

A mobile app is accessible at any time on the user's terminal, it can send push notifications, access the bluetooth, the camera, all the features of the phone or tablet. 

There are many good reasons to develop a mobile application, and several technical solutions:

  • Native mobile application: a different application will be developed for each type of device, using the manufacturer's specific language: an application for Android devices, an application for iOS (Apple)... This is the most time-consuming solution, but also the most personalized, which will make the most of the possibilities of each device and offer the best user experience.
  • Hybrid mobile application: we'll write the code once, and generate an application per type of terminal. This is possible using a framework like React Native, for example. It's faster and less expensive than a native application, but you have less possibilities than with native and you are dependent on a framework. 

A mobile application, whether developed natively or as a hybrid, also has its drawbacks. It is completely disconnected from the brand's main website, and must be downloaded via a store to be usable.

In e-commerce or social networks, for example, this is a weakness because it causes a break in the customer experience: the user clicks on a link or stumbles onto a website from his mobile browser, but has to install an application to access the content he is looking for. 

With this in mind, and in order to offer an answer to the mobile conversion problems encountered by publishers, Google has developed Progressive Web Apps.

What is a Progressive Web App?

A PWA offers a similar experience to a native mobile application, but it is a website, viewable from a simple browser. It is therefore also accessible from the desktop.

It was a Google engineer who defined the principle of PWAs in 2015, and since then, Google has strongly encouraged the adoption of this technology.

The PWA documentation released by Google defines the 3 pillars of PWAs:

  • A PWA is "capable": it takes advantage of the latest possibilities offered by APIs to offer features that were previously reserved for native applications: access to device files, notifications, camera...
  • A PWA is reliable: it is fast, regardless of the quality of the user's internet connection. It is also accessible offline. This is a particularly crucial issue in countries where the majority of the population is "mobile" and where Internet connections are not very efficient.
  • A PWA is installable: instead of opening in a browser tab, it can open in an independent window. It can be accessed from a shortcut added to the device's homepage, like a native application, but also from the "Start" menu of a PC.

"By the way, Google offers the Lighthouse tool, which allows you to audit your PWA to see if it meets the expected performance standards.

Thus, PWAs offer "the best of both worlds", between the website and the mobile or desktop application.

How does it work? To put it simply, a PWA is built from two bricks:

  • The Manifesto: a file that describes the data of the application: icon, name of the application...
  • The Service Worker: an asynchronous javascript process, which runs on the client side even when the application is not running. It uses a cache to store resources, and sends them to the browser to respond to requests sent by the client.

PWAs are therefore web applications that use standard web technologies (HTML5, CSS, Javascript), that run in a browser, but that can be installed, open in their own window and run offline.

Thus, a PWA is similar to a native mobile application, but with some differences:

  • PWAs can be installed from Google Play, the Android store, like any native mobile application, but not from the Apple App Store.
  • PWAs have access to some of the features of mobile devices (notifications, GPS, video and microphone sensors...) but with limitations: for example, they can't always access Bluetooth, or other native features (geofencing, Google Fit or Apple Health integration...). Here again, it's on Apple devices that the problem lies, because the last time I checked, it wasn't possible for a PWA to generate push notifications on iOS.
  • Unlike native applications, PWAs will not be able to take advantage of 100% of the computing power of the device and will therefore not be able to perform complex tasks (3D rendering, fluid graphic animations...). This limits the applications of PWAs in the field of video games for example.

Generally speaking, PWAs are much more interesting in an Android environment than on iOS. Let's not forget that it's Google who designed and popularized PWAs. Apple equips a quarter of the French population, and 14% of the smartphone owners in the world, so it's an important point.

Feedback: the benefits of PWAs

Google communicates on its website about use cases where the development of a PWA has allowed a brand to notice significant gains. These examples are interesting to understand concretely the advantages of PWA:

  • Twitter has developed Twitter Lite, a progressive web app that can replace the Twitter mobile application if desired. Twitter Lite has been deployed in some 40 countries, notably in Africa and India. Results: the number of pages per session has increased by 65%, the number of tweets sent by 75%, and the bounce rate has decreased by 20%.
  • AliExpress increased the conversion rate for new users by 104%, doubled the number of page views per session, and the time spent per session increased by 74%.
  • Trivago has increased the click-through rate of its hotel offers by 97%,
  • OLX, which runs classified ad marketplaces in many countries (India, Brazil, Indonesia, South Africa...) increased the click-through rate on their ads by 146%. Using push notifications, they saw a 250% re-engagement of users.
  • Treebo has increased its conversion rate by 4 times.
  • Alibaba saw its conversions increase by 76%.
  •, an Indian competitor of AirBnb, saw its conversions increase by 38% and its bounce rate decrease by 40%.

What can we learn from these impressive figures?

When you're a famous brand that naturally generates a lot of mobile traffic, it can be interesting to offer users to install a PWA rather than a mobile application .

A PWA is immediately added to the user's homepage, thus avoiding the friction caused by going to the store and downloading the app. This is especially true when users are reluctant to multiply the number of mobile applications installed on their smartphone, due to lack of storage space; it is also valid when the internet connection is not great.

As a result, these brands lose fewer users along the way, thus increasing their mobile conversion rate, and can re-engage these customers via notifications, which would not be possible with a traditional mobile website.

Progressive Web Apps: advantages and disadvantages

Now that we have done an overview of Progressive Web Apps and their possibilities, let's try to summarize their assets...and their limitations.

- The benefits of PWA

  • Development and maintenance costs are limited compared to native and hybrid applications: a single code for all devices, deployment and updates in real time without going through the validation of the stores;
  • The experience is more fluid for the user, who can immediately add the application to his home page without going through the store (especially true on Android);
  • PWAs allow users to re-engage via push notifications, just like a native mobile app (true only on Android) ;
  • Compared to native applications and mobile websites, PWAs are lighter, less resource and bandwidth intensive: they are fast and efficient. From this point of view, we can even say that developing a PWA is an ecological choice.
  • PWAs can work offline, both on the desktop and on mobile, which opens up many use cases.
  • Unlike a mobile application, which is only distributed on the stores, a PWA takes advantage of all the usual acquisition channels in the web, especially search engine optimization (SEO).
  • There's a lot of talk about mobile, but a PWA is also accessible on desktop. Microsoft is betting heavily on PWAs in Windows 10, and plans to gradually replace many classic apps (including Microsoft Teams) with PWAs.

- The disadvantages of PWAs

  • As we saw, Apple is not a big fan of PWAs. As long as the possibilities of PWAs on iOS (downloadable from the App Store, notification management, easy addition to the homepage...) are not the same as on Android, PWAs cannot be considered a credible alternative to native applications.
  • Access to hardware and operating system features remains limited, even on Android.
  • Doing without the stores can be an advantage for developers and users alike; but for brands, it means depriving themselves of an important visibility channel.
  • Technically, PWAs are still dependent on browsers. This requires significant testing, and is a source of bugs that should not be overlooked.

What future for PWAs?

A few years ago, PWAs were touted as the next revolution.

Where are we today?

It is clear that the enthusiasm for this technology has not lived up to its promise .

Apple's reluctance is a big part of it. But other signals suggest that enthusiasm is waning: Mozilla, for example, recently announced that it would end support for PWAs on Firefox.

From our point of view, the future of PWAs seems to be limited to certain specific use cases.

Is a PWA suitable for my project?

A PWA is a mobile website on steroids, but it opens up few new possibilities.

A PWA can't replace a classic mobile application: if you have a project that targets the general public, and you don't have a big reputation yet, you won't be able to do without the stores.

By the way, when we look for examples of PWA in France today, we often think of the newspaper L'Équipe, one of the first French sites to launch a PWA in 2017.

But let's not forget that :

  • The Team has a strong reputation and an ability to generate significant traffic;
  • The Team offers this PWA as a complement to the mobile applications deployed on the stores, not as a replacement for them!

Here are the use cases for which the choice of a PWA seems to us the most interesting:

  • You already have a public website, with a high mobile traffic (media or merchant site). Many users only visit it occasionally, and are therefore not inclined to install a mobile application. Offering them a PWA is a good way to increase their loyalty, improve their experience and increase the conversion rate.
  • You need your users to be able to access your website or web application offline. A good example is business tools (intranet, CRM, data entry tool...). The users of a company move on the field, and need to enter data even without connection, and synchronize them later with the central site. In this case, a PWA is a very good alternative to the mobile application, less expensive and just as effective.

In the case of a project launch, if you don't have a website yet, launching the development of a PWA can be a relevant choice, but here again, only if you need your users to access your service offline: for a simple showcase site, no need for a PWA!

Finally, we don't recommend considering the PWA as an MVP, as a V1 of your product, to then develop native applications when you have more budget. Indeed, this would require rewriting everything from scratch.

In addition, don't miss our list of technologies with a promising future that have been widely acclaimed by our developers. To download our Tech Trends 2021 guide, click here.

Simon Galet

Simon Galet

Architect developer @theTribe

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