How Bloomberg Used React Native to Develop its new Consumer App

Bloomberg’s new consumer mobile app for iOS and Android, launched yesterday, offers users a streamlined, interactive experience with easy-to-access personalized content, videos and live feeds featured across Bloomberg Media. To develop the app, the company used a new mobile software development framework. An engineering team at Bloomberg’s New York City headquarters developed the app using React Native, the first tool that truly delivers on the promise of cross-platform native app development.

React Native, developed by Facebook and released last year under an open source license, lets developers build a rich mobile user interface using JavaScript. It leverages the same fundamental UI building blocks as iOS and Android apps. With React, Bloomberg engineers were able to more easily and quickly rebuild the company’s consumer app for both mobile platforms, and include a host of innovative new features.

“The consumer mobile app was a huge endeavor because we had to transition the entire team to React Native,” says Gabriel Lew, a senior software engineer at Bloomberg who led the development team’s effort.

After testing and prototyping with React Native, Bloomberg decided to use it for the consumer app redesign. While other free software projects like Titanium and PhoneGap promise to offer developers a native look and feel, Bloomberg found that React Native was the best tool available in the market today to create native apps simultaneously for both iOS and Android platforms.

Before React Native, Bloomberg teams “would have developed the iOS and Android versions in parallel without being able to share most of the code they wrote, leading to delays and repetition,” Lew explains. By comparison, the React Native platform’s unified development capabilities and made for a seamless process that allowed each developer to focus on one feature at a time.

“That helped speed things along,” Lew recalls. It took the team of developers in New York just five months to develop the app—roughly half the time it would have taken had they not used React Native.

Bloomberg's Consumer Mobile Engineering team photographed at Bloomberg Global Headquarters in New York on December 13, 2016. Photographer: Lori Hoffman/Bloomberg.

React Native was created by Facebook to be learned once and written everywhere. With a “fairly easy ramp up,” Lew affirms, Bloomberg’s development team became fluent in React Native and was able to work seamlessly across its entire product portfolio.

Another benefit of React Native is that it automates code refreshes, accelerating the release of new product features. Instead of recompiling, your app reloads instantly. “Once users open the app, they get the latest update and will always have the best experience,” Lew says.

That same feature lets coders experiment, iterate and quickly push out upgrades with A/B testing. For example, before the app’s launch, the team tested user preferences by placing images on the left and right sides within the app, collecting data and metrics to identify what internal beta users favored. This was just one of the many experiments the team conducted to validate this tech and workflow.

Like all Bloomberg products, the new consumer app is designed to meet user needs and seamlessly integrate with their routines. Content can be personalized according to the user’s location anywhere—a dedicated editorial team curates news to reflect the time of day—and by field of specialization, such as Markets, Technology, Politics, Opinion, or Pursuits.

What’s more, users can access live TV or event feeds for on-demand viewing. Lew says React Native made it easy for Bloomberg engineers to “sprinkle in interactive animation,” such as a parallax of images in the news feed or the ability to swipe a headline to share or bookmark an article. It also enabled the team to ensure the continual updating of the app with market-moving news, data, and analysis, all of which is accessible via personalized widgets. There is no performance impact on media features like animation because the JavaScript is running on a separate thread.

“React Native is the best out there,” Lew says. “Expect it to appear in other Bloomberg mobile apps in the future.”