Progressive web apps: The mobile future?

Progressive web apps: The mobile future?

Agencies that can’t afford to pay a developer to build and maintain an app may want to consider progressive web apps, which offer advantages over traditional mobile applications and even browser-based apps because of their ability to work across multiple devices, their speed and the ease with which they can be developed and deployed.

Originally proposed by Google in 2015, PWAs combine the best of mobile and web applications. They look and feel like an app to the user because they’re built on the app shell model. They work for every user, regardless of browser or device choice, and can run offline or on low-quality networks.  Search engines can find them, they’re easy to share via a URL and they’re served via HTTPS for better security. And perhaps best for civic applications, they employ re-engagement features like push notifications.

Web apps, on the other hand, are built to be used in a common browser, but they have limited access to a mobile device’s features, such as the camera and GPS.  And although native mobile applications are more customizable than web apps and can take advantage of a smartphone’s features, they are expensive to build and maintain. PWAs are fast, work across devices, and do not need to be downloaded to the device because they are shareable as a web page.

PWAs are neither a website nor a mobile app. “The secret is in something called the service worker, which runs in the background,” InspireHUB Inc.’s COO Karolyn Hart wrote in a white paper.  A service worker, according to DigitalGov, is a JavaScript background task that replaces the traditional web cache with a cache application programming interface. “The API wakes up when needed and listens to network requests and saves or caches the static resources from the visited sites. This enables the PWA to function even when offline, making the app ‘always available.’”

“The more your users interact with the app, the more of the app is made available even when there is no internet connection. It ‘progressively’ becomes an app as it earns the trust of your users,” Hart said.

Flipkart, India’s largest e-commerce site, increased conversions by 70 percent when it switched to a PWA that increased site loading speed, according to Google Developers. Because 63 percent of Flipkart Lite users access the site over a 2G network, increasing load speed was critical.

“Users visit via their browser and find a fast, app-like user experience. When they come back, it loads nearly instantly, even on flaky networks,” the Google case study said. “Users can even continue to browse categories, review previous searches and view product pages -- all while offline.” Compared to its mobile app, Flipkart Lite uses three times less data.

Another benefit of PWAs is reduced cost because a single app will work on any platform. The United Kingdom’s Government Digital Service “banned” government development of mobile applications, saving $8.2 billion over four years, the former head of design for the UK’s GDS, Ben Terrett, told GovInsider. Instead, he favors responsive design websites.

While U.S. federal agencies lean toward mobile web design, they take a more flexible approach to mobile apps, the General Services Administration’s Jacob Parcell said. It depends on the problem an agency is trying to solve and the way users will most likely accomplish the task, he explained.

Mobile web is good for information, while mobile apps are good if a transaction or the technology of the mobile device is required, Parcell explained. Repeat usage and a large number of active users make web technology a better choice. Connectivity is another factor. If a user needs information that an app can store on the device and the user doesn’t have internet access, then a mobile app is better, as some resources reside on the device.

“[Progressive] web apps can replace all of the functions of native apps and websites at once,” said Ada Rose Edwards, a developer advocate for Samsung, writing for Smashing Magazine.

While there is no definitive delineation between a progressive web app and a website, Edwards noted that a progressive web app should be responsive, with the following characteristics:

  • Geared for mobile use on all screen sizes yet able to also work as a desktop website.
  • Capable of working offline.
  • Seamlessly touch and gesture capable.
  • Have app meta data to tell the browser how it should look when installed.
  • Able to receive notifications when the app is not running, if applicable.

At the same time, a PWA should maintain certain web-like properties. It should be able to work as a normal website and not locked into any browser or app store, with the ability to share the current URL.

“A good guideline is that, if you are building a new website from scratch, start off with a service worker,” Edwards said.

About the Author

Kathleen Hickey is a freelance writer for GCN.

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