The Story

The client’s existing Android app was built on Java, making maintenance and feature expansion challenging. Additionally, the UI relied on legacy components, limiting flexibility and responsiveness. To overcome these issues, we undertook a complete modernization effort—migrating the codebase, optimizing performance, and ensuring cross-platform consistency while maintaining seamless functionality.

Our client is a Sweden-based leader in energy-efficient heating solutions, aiming to modernize their mobile apps for improved performance, scalability, and seamless heating system management across Android, iOS, and web platforms.

Amit Jangid

Founder & CTO

Challenges

• > Migrating a large Java codebase to Kotlin without breaking existing functionality.

• > Implementing reactive programming with Kotlin Flows for efficient data handling.

• > Replacing legacy UI components with Jetpack Compose for a modern, scalable interface.

• > Ensuring smooth interoperability between old and new architectures.

• > Managing performance optimizations across multiple device configurations.

• > Implementing automated testing strategies to maintain stability during migration.

The Solution

We systematically modernized the Android app by transitioning from Java to Kotlin, improving maintainability and scalability. Kotlin Flows replaced outdated callback-based patterns, enhancing real-time data handling and responsiveness. The UI was restructured using Jetpack Compose, enabling a flexible, dynamic interface. For iOS, the app was built using Swift, ensuring native performance. The backend, powered by C#, JavaScript, and .NET Core, provided seamless data synchronization, while MS SQL, Cosmos DB, and PostgreSQL ensured secure and scalable storage. To maintain reliability, we implemented automated UI tests with Java, Appium, and TestNG, along with CI/CD pipelines using GitHub Actions for streamlined deployments.

The Outcome

The modernization efforts resulted in a faster, more efficient application with improved stability and maintainability. The adoption of Kotlin, Jetpack Compose, and automated testing significantly reduced development overhead while enhancing user experience. By upgrading the architecture, the client now has a scalable, future-ready app that supports seamless heating system management across platforms.