Nico Kastunowicz

Building a GDPR-compliant health-tech CRM for care service brokerage in the German social care market — managing the full pipeline from patient intake to benefit application. Working across the full stack: PostgreSQL with Row Level Security enforcing Art. 9 health data separation, TypeScript domain logic with Zod at every external boundary, and React UI on Next.js 15 and shadcn/ui. Features ship as vertical slices — migration, business logic, and component in one pull request. Integrations include cal.com for patient booking, the Gmail API for case-linked communication, and Sipgate for telephony, alongside a reporting system built on Postgres Views feeding an internal dashboard and automated partner reports.

Spent four years building enterprise financial planning and modeling software used by customers including Volkswagen and Mercedes Group. Developed real-time collaboration features enabling simultaneous editing of complex financial models, and drag-and-drop scenario planning interfaces that significantly reduced onboarding friction for new users. Contributed to a shared component library with Storybook to enforce UI consistency across a large codebase, and maintained a comprehensive test suite with Jest and Cypress. Also drove performance investigations into chart rendering bottlenecks, heavy data transformation pipelines, and large component trees — profiling and resolving issues that had real impact on responsiveness for enterprise-scale datasets.

Worked in an agency environment delivering a range of client projects, including the development of a B2B webshop for the Franke Group (global player in kitchen systems and supplies) and the creation of a React Native prototype app in the health sector. I collaborated closely with designers and stakeholders to translate requirements into clean, functional interfaces, balancing rapid iteration with maintainable, production-ready code.