* Developed shared code for Android and iOS with Kotlin Multiplatform.

* Integrated features with custom hardware over NFC-based communication channel.

* Built multiple methods of account recovery via hardware, cloud backup, Delay + Notify, etc.

* Provided technical, product, and design input for complex interactions between app, user, hardware, cloud, and server.

* Updated and composed dependency injection for multiple apps.

* Designed and implemented mobile feature flag system for controlling feature access.

* Planned major overhaul of legacy in-app storage.

* Organized and often presented team events to promote best practices and improve code quality.

* Developed features for Google Cloud Platform application.

* Implemented front-end features in React.

* Wrote and executed validation documents for new hardware.

* Provided on-site and remote support for factory builds in China.

* Worked with native libraries and JNI to support several generations of Square card readers over audio, Bluetooth, and BLE.

* Created pairing UI for wireless card readers.

* Developed and supported features for launch of Square Register in Australia.

* Implemented secure PIN entry system for chip-and-PIN markets.

* Created in-house localization utilities for formatting numbers, currencies, and dates.

* Developed country-specific payment types and features for foreign releases.

* Created EMV payment UI.

* Worked as part of a team to modernize the visual presentation of Square Register's UI, including styles, animations, and custom widgets.