Stephan Schulz

Building On's Multilingual Consumer App (Flutter)

Helped architect and build On’s first public-facing, multilingual consumer app for iOS and Android using Flutter. I co-defined the app’s layered architecture and led development of key features such as Product List, Search, Cart, and Checkout.

Owned the full lifecycle of a custom payment provider plugin (iOS & Android), including architecture, implementation, testing and documentation. Regularly reviewed pull requests with high attention to code quality and clarity, contributing to team-wide engineering standards.

Actively mentored colleagues, offering constructive code feedback and architectural guidance. Supported modular UI design with reusable components, introduced snapshot testing, and contributed to CI/CD workflows. Served as release manager in a rotating team system.

At Vivy, I led the design and implementation of a Server-Driven UI (SDUI) framework in Swift. The system used a modular design language with reusable components, enabling layouts to be composed dynamically from server data. I built a flexible rendering engine and defined the supported object types and behaviors.

I collaborated closely with Android engineers to establish a shared SDUI specification, ensuring consistent cross-platform behavior. The framework powered health journeys and custom flows authored through a node-based editor used by insurance partners.

Given the complexity of Vivy’s shifting codebase, I emphasized architectural separation and future-proofing. I documented the entire SDUI system to support maintainability and onboarding.

Additionally, I supported the hiring process by co-conducting technical interviews alongside the tech lead.