The Google Play and Apple App stores comprise roughly 2 million apps each, with the Apple App store alone accounting for more than 140 billion downloads since 2008. Mobile marketplaces are nothing if not robust, but the act of downloading apps has always been more popular than the act of actually using them. A 2016 study by research and marketing firm Localytics found that 20 percent of downloaded apps are used just once before they’re forgotten or deleted. On average, apps lose 77 percent of their users three days after installation, and that number climbs to 90 percent after a month.

One of the biggest challenges then for any developer is building an app that can sustain its user base. And while engineering longevity is more alchemy than science, developers can find plenty of ways to hedge that bet. We chatted with Rahul Jalali, Walmart Technology’s senior director of store and mobile systems, about four common characteristics that successful mobile apps embody.

Detail of iPhone smart phone screen showing newspaper app icons
Detail of iPhone screen displaying newspaper app icons

Cross-platform functionality

Building mobile apps to work across multiple operating systems is an obvious way to reach more users, but choosing between the native and hybrid route is a more nuanced decision. Going native enables developers to make the most of a given platform, but building multiple apps from scratch can be costly. On the other hand, building in HTML5 or leveraging a middleware solution can be a great cost-saving measure, but limits the degree of control a developer has over user experience.

“Ideally, we could go all native because you can exploit every feature a particular platform has to offer. For example, the camera feature on iOS is a little bit different than its Android counterpart,” Jalali said. “But when budget is tight and you don’t have the luxury of a large dev team, you have to compromise and go hybrid. At Walmart, we’ve been relatively successful with various open-source middleware solutions.”


The only thing worse than having no users at all is having a ton of users show up and receive error messages. To be sure, grappling with the needs of a large and ever-growing user base is a great problem to have, but it presents a considerable engineering challenge. At Walmart, even internal-facing apps can have an audience of at least a million users, meaning everything needs to be built from the ground up to scale.

Jalali suggests developers take a holistic approach and closely examine availability across each aspect of their core architecture, from their web and database servers to API structures and cloud platforms.

“The key here is planning up front, because if you start talking about scalability after the eighth app is developed, it’s like replacing all the components of a car while driving it 100 miles,” he said.


Whether they’re building a multimedia content app or an e-commerce platform, developers must have a keen understanding of what users are looking for and be able to deliver that. Personalization has helped make one of the largest e-commerce sites on the planet, and it’s a core component of the company’s burgeoning grocery app.

“As a consumer, I’m looking for the app to understand what I’m looking for and make my time with the app more productive,” Jalali said. “Walmart Grocery is a glowing example of that.”

Walmart’s personalization engine is a product of years of development and tinkering. It powers everything from home page customization to search engine results.

User-friendly experience

Crafting a user-friendly experience is no small feat. For proof, look no further than the rancor that erupts anytime Facebook or Twitter release an update. The difficulty of delivering a great UX on a mobile device is compounded by the fact that screen real estate is considerably more limited than on a desktop. Developers have about five inches of display space to execute a functional and intuitive design that allows users to navigate the app in as few steps as possible.

Fortunately, there are a variety of tools that allow engineers to explore UX directions before having to commit significant resources.

“One thing that’s worked out really well for us is the concept of rapid prototyping,” Jalali said.

Through rapid prototyping, Jalali and his team are able to assemble a minimum viable product without having to write a single line of code. The prototype can then be released to users for feedback, which is then used to fine-tune the product.

Are you an app developer looking to work in a fast-paced environment with cutting-edge technology and open source tools? Walmart Technology is hiring! Check out Walmart Technology opportunities in California or search all other locations.

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