CV

SUMMARY

Senior software engineer with 30 years of professional experience, specializing in TypeScript, React, and Node.js. Building AI-powered applications and agentic systems with the Anthropic SDK and Vercel AI SDK, and accelerating development using agentic coding tools (Claude Code, Cursor). Proven track record of designing and implementing scalable systems, leading engineering teams, and introducing strategic technologies that reduce technical debt and accelerate product delivery.

EXPERIENCE

Parloa – AI-powered contact center platform
Frontend Developer | Mar 2025 – Dec 2025

Designed and implemented server-driven UI (SDUI) package enabling backend developers to build service UIs, standardizing UI development across 7 teams
Built core platform features in $3 billion AI scaleup serving Booking.com, American Express, Decathlon, and Allianz
Developed primarily through agentic AI coding (Claude Code, Cursor) in a large production codebase
Tech: TypeScript, React, Next.js, Ant Design, Vite, Storybook, Vitest, Testing Library, tRPC, OpenAPI

seabo – Freightship Chartering SaaS Platform
Lead Full-Stack Developer | Oct 2022 – Apr 2024

Selected and introduced NestJS as strategic replacement for the legacy PHP backend; built and extended chartering marketplace (React, Node.js)
Built vessel database and Stripe subscription billing (backend and frontend); rebuilt realtime updates with socket.io
Mentored fullstack developers and drove technology decisions (REST APIs, BullMQ job queues, TypeORM)
Tech: TypeScript, React, Node.js, NestJS, MySQL, TypeORM, Stripe, Redis, BullMQ, socket.io

ISV (Confidential) – SaaS Development
Lead Frontend Developer | Jul 2020 – Sep 2022

Modernized 7-year-old JavaScript React codebase: migrated to TypeScript, introduced automated testing, adopted component library
Led and coached 3-person frontend team, increasing velocity while improving quality and adding new features to legacy product
Tech: TypeScript, React, Redux, React Query, Jest, React Testing Library, Ant Design

Zalando – Procurement Portal
Lead Frontend Developer, Coach | Sep 2019 – Mar 2020

Led greenfield frontend development for procurement platform supporting €1 billion in annual fashion purchases
Selected technologies, designed architecture, and coached 4 developers with React and MobX workshops in cross-functional team of 12
Tech: TypeScript, React, MobX, GraphQL, Apollo, Ant Design, Material-UI, Jest, React Testing Library

DMG – Dentamile Connect (Dental CAD/CAM SaaS)
Frontend Developer | Jan 2019 – Aug 2019

Built SaaS for digital production of dental products (crowns, bite splints) with browser-based 3D CAD using WebGL
Designed and negotiated API between SaaS and WebGL CAD component built by partner agency; set up UI component library
Tech: JavaScript, React, Redux, Node.js, REST, Swagger, Jest, Storybook, Webpack

Intersection (USA) – Smart City Kiosks
Frontend Developer | Oct 2018 – Dec 2018

Built maps feature for interactive kiosk systems; supported Chicago Transit Authority rollout
Tech: React, Redux, JavaScript, SVG, Jest, Storybook

Earlier Career (1996–2018) Former CTO and co-founder of Papersmart and Balao; team lead at Fyber and BizSphere; senior developer at enterprises including SAP, O2, and Reuters. VP Research & Development at Netlife. Expertise in Ruby on Rails, Java, and C++. Full project history →

PROJECTS & PUBLICATIONS

Billet – CLI coding agent built directly on the Anthropic SDK: agentic loop, bash and text editor tools, plan mode, eval suite (TypeScript, Anthropic SDK, Bun) – GitHub
Smart Rename – AI-powered desktop app that extracts invoice metadata and auto-renames files (Vercel AI SDK, Evalite, Tauri, TypeScript, React) – stefanwille.com/smart-rename
Recto – published web tool for planning book page layouts, in production use on a 400-page book project (TypeScript, React, Supabase) – rectostudio.com
Author of two books on Java and enterprise software development

EDUCATION & LANGUAGES

Bachelor in Computer Science, University of Hamburg · Certified Scrum Master (CSM)
German – Native (C2) · English – Fluent (C1)