Using React Native and Expo to power a leading UAE broker’s mobile trading app

Adaptive partnered with a leading UAE-based broker to design and deliver a high-performance mobile trading app on an ambitious timeline, using a small team of expert web developers to build for both iOS and Android simultaneously. By combining React Native and Expo with our deep experience in real-time streaming architecture, we created a retail trading application that:

• Supports more than 15,000 active traders.
• Processes over $30 billion in trade volume.
• Provides a seamless bilingual experience in both English and Arabic.

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Why traditional native mobile app development wasn’t the right fit

Native iOS and Android applications are often built from two separate codebases. This requires two teams of skilled developers who can program in Swift/Objective-C and Kotlin/Java to a very high level. Given our short timeline and small team of skilled web developers, this would be a difficult task.

Fortunately, there’s a framework combination that can alleviate these technical constraints… React Native and Expo.

Why we chose React Native for mobile trading app development

Adopting React Native gave us the power to build both platforms simultaneously, without previous knowledge of native code. Out of the box, React Native allowed us to create reliable and performant UIs with React (something we’ve got plenty of experience in). Our development process also remained the same, with tools like TypeScript, Prettier and Jest being fully supported, giving us a familiar development environment.

However, React Native requires Xcode and Android Studio to be installed, with the responsibility of managing SDK versions and upgrades pushed to the developer. We didn’t want to implement a complicated build process or manage complex upgrades, which is where Expo became an essential tool for us.

How Expo accelerated mobile app delivery and deployment

By using a managed Expo project, we accelerated our development. It offered us a managed pipeline for building native apps and a well documented module ecosystem. This enabled us to integrate with platform-specific features like biometrics and camera systems, with excellent support for future iOS or Android SDK versions.

Building and deploying updates to Apple and Google app stores seemed like a daunting task at first. However, using Expo’s application services handled automatic submissions and removed complexity around app store upgrades. There’s also excellent support for Expo and React Native upgrades with help from the active Expo community.

We were initially concerned about Expo being a limiting factor for integrating native iOS and Android libraries (such as an ID verification library). Fortunately, Expo provides a few options here with its config plugins and modules API, giving us the flexibility to do this with limited native mobile code experience and staying in the managed Expo ecosystem.

Building a multilingual CFD and Equities trading app

We built an app that allows users to trade CFDs and equities. With the client being based in the UAE, we added support for both English and Arabic languages throughout. Implementing support for languages that are left-to-right and right-to-left would usually require specific native knowledge, but React Native made this feature achievable with built-in support for right-to-left mode.

Most retail trading applications integrate with charting, with features like drawings and studies being well supported. From our research, it appeared most financial charting libraries were typically built for the web. To accommodate this, we embedded a well known chart library inside a React Native WebView along with a custom bridge layer, making the chart feel well-integrated and highly capable.

Supporting real-time market data streaming with Adaptive’s technology platform

Maintaining a reliable connection for mobile users is a challenge:

1. A device receiving hundreds of price ticks per second may suffer from performance issues and delayed information on slower connections
2. Users could walk through tunnels, switch between WiFi and 4G/5G networks and background the app for hours at a time

This is where we really benefitted from our technology-based backend. It provided us with a highly performant data stream over a single WebSocket connection, supporting our high-throughput data requirements for pricing, accounts, positions and order event streams. There’s great support for reconnection and authentication, making it possible for us to handle mobile devices frequently changing their connection status.

But here’s where we hit another potential problem. How do you manage this huge amount of data being streamed to a mobile device? How can you ensure the app is capable of rendering these updates and making sure your components respond to all these events?

Implementing RxJS to build a powerful responsive architecture

RxJS is a library we know well at Adaptive, due to its excellent pairing with data streams. By utilising RxJS on the client side (and pairing it with React RxJS), we built a powerful responsive architecture. This allows us to respond to situations like a device disconnecting from the backend or the app being backgrounded for long periods of time. Our entire connection layer was built to manage reconnections gracefully and re-authenticate users fast.

Utilising streams gave us the power to build responsive UI components. For example, our order tickets involved quantity validation, real-time price updates, buying power checks, commission, and market depth calculations. By fetching and managing this data with streams, we built intricate financial components that could react to each other in real time, with the ability to compose calculations to support complex business features on the UI.

Lessons learned from building a high-performance financial trading app

React Native coupled with Expo is an excellent choice for a high-performance financial application. Support for the framework has really matured, enabling small teams to deliver what would previously have required large platform-specific teams.

The outcome was a highly performant, intuitive retail trading application offered in both English and Arabic. The well-designed architecture supports real-time streaming and highly capable UI components, making it possible to support 15,000 traders and process more than $30 billion in trade volume – numbers that are likely to grow.

For us, this project reinforced an important lesson: delivering a successful trading application is not about the frameworks alone. It is about combining the right technology choices with a robust real-time architecture and deep domain expertise. The tools helped us move faster, but the outcome was driven by the engineering decisions behind them.