Ban – Kotlin, Android, Jetpack Compose

One of the world's largest AI companion applications, serving over 40 million users worldwide, focused on personalized, emotionally engaging conversations for user well-being. Work centered on modernizing core parts of the Android application to improve scalability, maintainability, and user experience.

• Led a large-scale refactoring initiative affecting more than 40 million user accounts;
• Re-architected the app's memory system using modern Android architecture principles;
• Redesigned onboarding flows, improving maintainability and reducing user drop-off;
• Built subscription-related features that contributed to a 30% increase in revenue;
• Collaborated with cross-functional product, design, and backend teams to ship production-ready features.

Android SDK for indoor location and navigation without additional hardware, along with a demonstration application used by enterprise customers to showcase indoor navigation capabilities inside real venues.

• Helped prepare the Android SDK for production release;
• Led development of the Android demo application;
• Developed indoor navigation features including routing and map rendering;
• Implemented user orientation using ARCore and Android sensor APIs;
• Improved location estimation using WiFi scans and sensor fusion;
• Designed reusable SDK components for enterprise customers;
• Collaborated closely with backend and product teams.

A cashback application for a local startup, enabling users to earn rewards when shopping at partner stores by scanning QR codes. The application surpassed 100,000 downloads.

• Led Android development from early stages of the product;
• Designed scalable application architecture using MVI;
• Implemented QR-code based cashback functionality;
• Integrated Google Maps for partner store locations;
• Collaborated closely with designers and product managers;
• Helped shape product functionality in a startup environment.

A mobile application for a Dutch museum, enabling visitors to browse exhibitions and listen to guided audio tours. The application reached over 50,000 downloads.

• Delivered the Android application end-to-end for an international museum client, handling both feature development and release management;
• Built exhibition browsing and multimedia playback features with synchronized audio tours;
• Implemented offline caching for audio content to support uninterrupted use without network access;
• Worked directly with stakeholders across multiple countries to align on scope;
• Shipped several production releases following modern Android practices.

Mobile banking application used daily by thousands of customers for secure digital banking. Work involved modernizing an existing codebase, improving performance, and delivering new banking features while maintaining high standards of reliability and security.

• Released a major new version to more than 10,000 daily active users;
• Added new banking features while meeting strict performance, stability, and security requirements;
• Worked closely with backend engineers, QA, designers, and business stakeholders;
• Maintained and modernized a legacy Java codebase as part of an ongoing migration;
• Took part in architectural discussions and code reviews;
• Resolved production issues reported by live users.