Progressive Web Apps: What you need to know

Sush Labs

A Progressive Web App (PWA) is a type of web application that utilises cross platform app development technology to deliver web pages that are optimised for mobile. 

PWAs provide the feel of a native application while browsing the web on a mobile device, without requiring the user to install an app on their phone. However, a user also has the option to install the web app on their mobile homescreen for easy access. Essentially, PWAs provide cohesive web experiences that can be accessed on different devices than a desktop computer.

For many companies PWAs are relevant as they provide a way to improve mobile experiences without having to invest in native applications. In fact, even companies with a dedicated mobile app may also want to implement a PWA.

The benefits of PWAs

PWAs are arguably reliable, fast, responsive, installable, and can help to boost user engagement and retention. More specifically, PWAs provide fast loading speeds and can be opened even when there is no network or only a low-speed connection available. Load speeds are possible because with PWAs, several elements of the web page are cached the first time you open it. PWAs also don’t require the processing power or storage of a native app, meaning interactive elements respond immediately to the user’s gestures.

responsive design illustration for different tech sizes of devices

Scrolls and page transitions are smooth when users are interacting with a PWA, and the layout is able to adapt to all different sizes of devices. Factors such as home screen installs, splash screens, push notifications and offline abilities make the PWA seem more like a native app and helps to keep users engaged. 

Finally, as PWAs are smaller and faster to install, it can be easier to onboard users from the website to the app, reducing customer acquisition cost (CAC). Because PWAs exist on the web, they can be found through a search engine or shared on social media. Discoverability is also empowered through the fact that users don’t have to go to a native app store to find, authenticate and install the application. A PWA can also be less disruptive to update than a native app as it doesn’t require any manual installs or updates.

A closer look at the mechanics 

Taking a closer look at the technical components of PWAs can help us to understand how they function and their various use cases. Three key elements of the PWA are the service worker, manifest file and HTTPS.

The service worker is essentially lines of JavaScript code that acts as a proxy between a browser and network, and allows the PWA to have instant access to cached resources. It builds the offline-first experience by utilising the browser's cache API, ensures fast load times, enables users to access the app even with slow or patchy networks, and also manages push notifications.

The manifest file is a config JSON file that contains the information of how your application appears to the user and makes your app discoverable. The script file includes information about the icon to be displayed on the home screen when installed, the short name of the application, the background color, the theme and the description. This component makes the installation of web applications to a home screen possible.

PWAs must be served over a secure network, meaning they require HTTPs. The majority of features related to a PWA, including geolocation and service workers, are often only available once the app has been loaded using HTTPS. Therefore, PWAs ensure that you are applying security best practices and are establishing the application as a trusted site.

Choosing between native applications or PWAs

When it comes to choosing between a native application and a PWA there is no definitive answer. Ultimately your choice comes down to your specific requirements and business goals.

Some argue that while a PWA does provide faster load times, simplified updates and an improved user experience, they are still in their nascent stage. For instance, iOS doesn’t support all PWA features currently available. This means push notifications, background sync and web manifest files are still not entirely supported on the Safari browser. 

connection of various computer-enabled gadgets

This appears to be changing as Apple slowly encourages users to shift from the App Store to create web applications instead. However, as PWAs continue to improve, native applications are also constantly evolving, with greater opportunities to make use of smartphone features such as sensors, GPS, touchscreen and haptics, and more. 

As technology improves and the likes of Apple and Google invest more into PWAs, it’s possible that they will come to stand alongside native apps. Even so, at Sush Labs, instead of focusing on finding the ‘best’ technology, we encourage our clients to look first at their project, customer expectations and overall goals, and then consider what technology will best serve the business. This approach ensures we successfully implement digital initiatives that meet the decided business goals.

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