How Flutter Transformed Our Decade-Old Native Apps

23.04.2025

In this article, I will share our journey of migrating from legacy native apps to Flutter, the challenges we faced, and the impact it had on our development process, team efficiency, and overall product experience.

The Challenge: Legacy Native Apps and Growing Complexity

For over a decade, our mobile apps relied on separate legacy codebases for iOS and Android. While these codebases were instrumental in our early success, managing two distinct platforms became increasingly unsustainable: 

Maintenance Overhead: Managing two codebases demanded significant engineering resources. Updates, bug fixes, and ongoing support became increasingly time-consuming, resulting in rising operational costs. 

Scaling and Innovation Challenges: Adding new features required duplicating efforts across both platforms, leading to delays and longer time-to-market. Meanwhile, technical debt had accumulated in the legacy code, making innovation harder and further slowing our development process. 

The Solution: Adopting Flutter

To address these challenges, we evaluated several cross-platform frameworks. Flutter, Google’s UI toolkit, emerged as the ideal choice due to its clear advantages: 

Unified Codebase: Flutter’s “write once, run anywhere” philosophy allowed us to consolidate iOS and Android development into a single codebase, significantly reducing development and maintenance efforts. 

Expressive and Flexible UI: Flutter’s declarative UI framework made it easy to create pixel-perfect, responsive designs that matched the performance of native apps. 

Rapid Development: The Hot Reload feature sped up our development process, enabling near-instantaneous updates and faster iteration cycles. 

Active Community and Ecosystem: Flutter’s vibrant community provided a wealth of resources, libraries, and support, helping us build efficient solutions more quickly. 

The Migration Process: A Smooth Transition

Switching from our long-standing native apps to Flutter required careful planning and execution. Here’s how we ensured a seamless migration: 

  1. Strategic Planning: We conducted an in-depth analysis of our apps, identifying common features across platforms and prioritizing critical elements for migration to achieve early wins. 
  2. Re-architecture and Rewrite: Rather than simply porting code, we re-architected and re-implemented the apps in Flutter. This allowed us to eliminate legacy technical debt and adopt modern, scalable practices. 
  3. Developer Up-skilling: The transition wasn’t just about technology; we also prioritized up-skilling our developers. By attending Flutter conferences, participating in workshops, and fostering collaborative development, we ensured a smooth transition and strengthened teamwork. 
  4. Thorough Testing: We heavily invested in testing, including automation and user acceptance tests, to ensure the quality and stability of the new apps before launch. 

The Impact: Clear Results

Migrating to Flutter has delivered measurable results in several key areas: 

90% Code Sharing: With a unified codebase, we now support all four of our production apps, significantly reducing development and maintenance costs. 

Reduced Engineering Effort: Our team is now half the size it was before, enabling us to allocate resources to other critical business areas and improve overall efficiency. 

Faster Time-to-Market: New features, bug fixes, and updates are deployed much more quickly, helping us stay competitive and better serve our users. 

No Quality Sacrifices: Our new Flutter apps deliver native-level performance, providing a seamless, consistent experience across both iOS and Android. 

Lessons Learned: Every Framework Comes with Unique Challenges

Although the migration was a success, it came with its own challenges: 

Initial Learning Curve: Up-skilling developers required time and effort, but the long-term benefits made it worthwhile. 

Platform-Specific Customization: Certain platform-specific features required extra work to integrate smoothly into the unified codebase. 

By proactively addressing these challenges, we paved the way for a smoother transition. 

Start Your Flutter Journey

Migrating to Flutter was a game-changing decision for us. It helped reduce costs, accelerate development cycles, and unlock new opportunities for innovation. If you’re facing similar challenges, consider exploring Flutter – it could transform your development process too.

Author

Lanh Vo
Senior Mobile Engineer & Tech Lead

Automotive

Marta Andreoni

Head of Design for Automotive

Introduce yourself and your role at SMG

I’m Marta Andreoni, Head of Design at SMG Automotive. I lead the design and UX writing team shaping AutoScout24 user experience. 

In my role, I wear many hats. My main focus is ensuring we stay true to our vision “simplifying people’s lives and connecting humans through innovative digital platforms” and our brand promise, “make it happen”. I challenge my team to think user-first, push for innovation, ease of use for our customers and make forward-thinking decisions, even within business and technological constraints.

 A big part of my role is supporting each designer’s growth, motivation, and career development. Through one-on-one coaching, mentoring, group work, and projects, I help my colleagues set and achieve their goals while fostering new learning opportunities.

What helps you feel empowered and confident in your role?

If I had to mention one thing I would say “being proactive” has been key to feeling more empowered. I enjoy solving problems, so when issues or opportunities arise, be it in the product, market or the team, I get curious and I proactively investigate the reasons and try to bring inputs to be discussed with others, this makes me feel I can be part of the process or solution and my point of view is going to be taken seriously. My optimism also plays a role, giving me confidence that even the most complex challenges can be solved. 

Besides, having trust from other managers and colleagues makes me feel in a safe environment where I can take ownership on topics I’m passionate about. 

What’s one thing SMG does well in fostering an inclusive workplace? What more can be done to amplify and support different perspectives in the workplace?

In my experience, we strive for balancing top-down and bottom-up inputs, ensuring employees can influence product directions, processes, and culture. People are approachable, and our strong feedback culture helps voices be heard. Across SMG, initiatives like regular People & Culture Surveys, topic guilds, and events in our locations across the world foster open exchange and mutual learning.

That said, I’ve noticed that quieter voices sometimes get less space, or interacting with top management can feel intimidating, especially when giving critical feedback. To make participation more inclusive, we could apply more facilitation and group work techniques like structured turn-taking, written input, and smaller group discussions – ensuring everyone, regardless of confidence level, seniority or personality, feels comfortable contributing. 

Design is often about seeing the world differently. How do unique perspectives contribute to more innovative, inclusive, or impactful design?

Design is about understanding diverse user personas and perspectives to create solutions that truly meet their needs or create new opportunities. I believe in the power of collaboration to shape user experiences – bringing together different disciplines, backgrounds, and lived experiences helps challenge assumptions, uncover blind spots, and drive more inclusive, innovative, and impactful solutions.

Looking back on your career, what’s one lesson or piece of advice you wish you had known earlier as a leader in design?

There are three things no one really prepares you for as a design leader: dealing with constant change, facing failure and handling emotions at work. These topics aren’t talked about much until you face them. I was lucky to learn from others’ experiences, but much of it came through my own.

One thing I wish I had understood earlier is the power of emotional intelligence, my job is no longer about the content and the design, it is about people. Self-awareness, not just of your own emotions, but also how others feel and react, can be the difference between conflict and harmony, frustration and clarity. The more I grow as a leader and designer, the more I realise that design isn’t just about doing the design job, delivering solutions on the market: it’s about navigating people, their emotions, and making change more acceptable and transforming issues into opportunities, both within the organisation and through great products.

 

Fotos vom Management mit und ohne Hintergrundfarbe als ZIP-Datei

Logo zum Download in allen Versionen