Willi Krappen

Fullstack Product Engineer

I build considered web products — from concept down to the details.

Ten plus years building software for agencies, startups and non-profits. Focus: TypeScript, React/Next.js, Node and 3D web.

Through-line

Typed graph as canonical state, AI as a tool-using citizen with a hard schema, event-sourced replay, registries as the only extension surface. Six projects, one worldview.

Selected work

Recent projects

pagebee.de
2025

pagebee.de

Multi-tenant SaaS that lets businesses tailor their website by chatting with an AI — per-tenant git repo, preview, Netlify deploy on approval.

Next.js 14TypeScriptTurborepoPostgres
2021–2024

Lemonverse

Lemonverse GmbH

Co-founded a Münster-based agency for industrial VR hands-on training. Concept through to on-site hardware deployment — with a progress dashboard for training KPIs.

ReactTypeScriptThree.jsReact Three Fiber
Drone Show Designer
WIP
2025

Drone Show Designer

Browser-based, node-based editor for aerial drone light shows: a graph model as single source of truth, live 3D viewport, deterministic bake pipeline, AI agent with 30+ tools operating directly on the graph. Work in progress — live and functional, still under active development.

TypeScriptReact 18Three.jsReact Three Fiber
LifeOS
2025

LifeOS

Personal commitment system: Telegram-first capture, AI structuring, relationship memory, weekly review. PWA with push, everything modelled on a single commitment table.

React 18ViteTypeScriptTailwind
Plainy
Case Study
2025

Plainy

Recursive planning pipeline of eight typed Anthropic agents: turns a single sentence into a TypeScript-contract-backed TaskBrief that Claude Code translates directly into working code.

React 19ViteTypeScriptTailwind v4
Multi-Agent Canvas
Case Study
2026

Multi-Agent Canvas

Watchable multi-agent system: a Sonnet orchestrator delegates to parallel Haiku workers, two critics debate, a judge decides — all streamed live onto a graph canvas, every session reproducible as an event-sourced permalink.

Bun 1.3HonoBun WebSocketlibSQL (Turso-compat)

Stack & skills

Frontend

JS/TSReact / Next.jsHTML/CSSTailwind / shadcnthree.js / R3F

Backend

JS/TS/NodeExpressSQL / Postgres / MongoDBORM (Prisma / Drizzle / …)PythonPHP

Tools & skills

GitJira / ScrumUNIX / Linux ServeradministrationWindsurf / Cursor / Claude