At Kleinanzeigen, I defined technical solutions and API contracts with Product and Backend teams, then owned delivery of three marketplace features that improved listing completion. I also diagnosed production crashes and UI inconsistencies, using Claude Code to speed up crash-log triage.
At ADAC Kreditkarte, I co-designed API contracts for transaction flows and implemented and refined 3DS authentication. I stabilized TCA modules and helped bring key flows to WCAG 2.1 AA accessibility compliance.
At MyFitnessPal, I led the migration of five core modules from MVC and Objective-C to MVVM and Swift, reducing regression incidents. I improved the crash-free rate from 99.2% to 99.6% by resolving production threading and memory issues, and owned the A/B testing infrastructure and experiment lifecycle across iOS releases.
In freelance and contract projects, I built NoCatfish solo for release on the App Store, improved Emeritus stability by refactoring and fixing more than 50 bugs, and worked on core commerce flows for Express. My work spans Swift and Objective-C modernization, modular architecture, testing, and production stability.
