Sometimes the path to financial independence isn’t that complicated — you just need the right app for it. And sometimes the path to that app is surprisingly straightforward as well. We proved this together with froots when we transformed their successful web app into a full-fledged iOS and Android FinTech app in just three months. What emerged impressively shows how modern technologies and a well-coordinated team can combine to create a real game-changer.
froots had already developed a great responsive web app that was already being used successfully. Users can seamlessly manage their investment portfolios through a dashboard, create new depots via sophisticated onboarding flows including KYC (required for financial services), and access educational components to help users make more informed financial decisions. The platform also helps track detailed transaction histories and monitor portfolio development over time.
However, in an era where financial apps have become the standard, froots users also wanted to manage their investments natively on the go. The challenge was clearly defined: How do you bring an already successful web app quickly and efficiently to the app stores without losing months or blowing the budget?
The first consideration was obvious: Why not just wrap the existing web app as an app? The idea here would have been to render all screens as web views. This approach would have saved time and resources, but the user experience would have suffered as a result. Because no matter how well you implement web views, it’s simply not a native app. Additionally, the Apple App Store doesn’t allow apps that aren’t “legitimate” apps — meaning something that could just as well be opened in a browser doesn’t qualify as a legitimate native app. This idea was quickly discarded.
Plan B would have been completely native development. Technically clean, optimal in the long run, but with one decisive disadvantage: you have to start completely from scratch. This wouldn’t have just taken months, but would also have rendered all the already developed and tested features of the web app unusable for the native app. Plus, there’s the future challenge of synchronizing further developments for both the web app and native app.
So we developed Plan C: the hybrid approach. Instead of going to the extremes of “everything WebView” or “everything native,” we decided on a mix. The core functionalities would be developed natively — what users use most frequently and what needs to feel most like a “real” app. Secondary functionalities, however, would initially be integrated as WebViews to quickly provide the full range of features.
This approach brought several decisive advantages. On one hand, we could start implementation immediately without spending months creating foundations. Apple App Store requirements were met since enough native functionality was present, and the app still feels like a real native app, which it actually is. A major advantage is the aspect of continuous development: as soon as the froots web app is expanded with new features, these can simply be made available in the native app via a new web view. We thus create a single source of truth.
When choosing the tech stack, the decision quickly fell on React Native and Expo — and for very well-thought-out reasons. Since froots’ web app already uses React and Next.js, React Native offered itself as a natural evolution. This decision made it possible to reuse a lot of existing code instead of starting completely from scratch.
The React Native know-how is already present at froots through web app development with React, which drastically reduces the learning effort and simplifies future developments. Additionally, both applications are in a monorepo: modules can be shared between both projects.
The decision for Expo even opened up an interesting future perspective: once the Expo app reaches the complete functionality of the web app, it could even completely replace it, since Expo can also render on the web.
Another decisive factor was our experience with Expo and React Native at &. We’ve already built several apps that tens of thousands of users use simultaneously, and can scale well accordingly. Therefore, we know how to optimize processes, quickly get to test builds, and put early versions in customers’ hands fast.
The general advantages of Expo also came into play: simplified development, over-the-air updates, a robust ecosystem, and the ability to quickly test on both platforms without having to set up separate development environments.
As expected, there were some challenges from the transformation from web to native app that kept us on our toes:
Component Library: froots’ web app used Mantine, a component library for web development that isn’t compatible with React Native. We needed an alternative that looks and behaves similarly, so we could reuse as much code as possible. Our solution was Tamagui — a modern component library that allowed us to keep the design consistent while still leveraging native advantages.
Shared Design System: Mobile works differently from the web. Components like dropdowns, date pickers, or number inputs behave completely differently on touchscreens than with a mouse and keyboard. We had to develop a shared design system that works for both worlds without either side having to make compromises.
Navigation: Additionally, in a web app, you navigate linearly — forward and back, link to link. In a native app, users expect stack navigation, tab navigation, dialogs, and gestures. We had to translate proven web concepts into mobile navigation patterns without compromising usability or changing the design too much.
Guidelines: While web apps must follow things like best practices and privacy guidelines, native apps additionally have the guidelines of Apple and Google app stores. So we had to find that sweet spot between those three guidelines.
Platform-Specific Adjustments: React Native promises cross-platform development, but in practice, platform-specific adjustments are still necessary. Different OS versions behave differently, and certain smartphone brands have their quirks. What looks perfect on an iPhone 16 can look completely different on an older Samsung device. The only thing we could do here was: test, test, test.
WebViews Integration: Our goal was to integrate WebViews as seamlessly as possible. Users shouldn’t notice that they’re in an embedded browser. This way, we were able to blur the lines between native and web so that the technical implementation stays in the background from the user’s perspective.
The most important insight was probably this: just because a web app is finished and successful doesn’t mean it can simply be transferred 1:1 to mobile. Mobile has its own laws, its own possibilities, and its own limitations. Understanding and respecting this was the key to a successful app.
Despite all challenges, we managed it in just a couple of months — and that was mainly due to the team. Close communication between froots and & was crucial. We weren’t just external service providers working through requirements, but formed a joint team. This integration enabled quick decisions, direct feedback, and a shared vision.
The hybrid approach proved to be the golden middle way: we could focus on the essential, build on existing foundations, and didn’t have to start from zero. At the same time, the path is clear for future fully native implementations whenever they make sense.
Today, froots users can natively manage their financial future on iOS and Android. The complete dashboard with all depots, the thoughtful onboarding flow, the entire transaction history, and depot tracking — everything they know is also there in the app. Everything works quickly and intuitively; everything feels like an app that was developed from the ground up for mobile.
Three months. That’s all the time it took to develop a fully working MVP from a vision. This only succeeds when an experienced team relies on proven technologies while proceeding strategically. The project showed us that even the most ambitious goals can be achieved in the shortest time with a methodical approach and the right team setup — while also being really enjoyable.
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