I'm a full-stack developer, engineering leader, and CTO with over a decade of experience building end-to-end systems, AI infrastructure, and products at the intersection of technology, sustainability, and design. I specialize in creating scalable, user-centric applications with modern tech stacks, from frontend interfaces to backend services and infrastructure.
- ⚡ Learning: AI Agents (LangGraph, n8n, Zapier), Federated Learning
- 💬 Expertise: Full-stack architecture, AI pipelines, startup strategy, MVP development
Led and contributed to multiple full-stack projects serving 20,000+ students and staff:
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Lead Full-Stack Developer for comprehensive course management system
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Key Projects:
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kurs-pm-data-admin-web— Full-stack application with ReactJS frontend, NodeJS/Express backend, and TinyMCE integration. Built complex state management for multiple editors, implemented real-time updates, and designed scalable data structures. 1,062 commits:467,337++177,567-- -
kursinfo-admin-web— Full-stack solution with ReactJS frontend, NodeJS/Express backend, and OAuth integration. Developed from scratch, implementing secure authentication, real-time preview, and efficient data management. 781 commits:158,710 ++414,791 -- -
kursinfo-web— Full-stack platform serving 20,000+ students with React frontend and NodeJS backend. Implemented responsive design, accessibility features, and optimized performance. 450 commits:90,271 ++271,339 -- -
kopps-public-react-web— Full-stack application with React frontend and NodeJS/Express backend. Built advanced search functionality, course filtering, and program management. 337 commits:56,058++ 54,522--
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Technical Lead and API developer for core backend services and API architecture
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Key Projects:
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kurs-pm-data-api— RESTful API service with NodeJS/Express, implementing complex data models, caching, and rate limiting. 203 commits:41,769++ 32,210-- -
kursinfo-api— MongoDB-based API service with NodeJS, handling data aggregation, authentication, and real-time updates. 61 commits:19,095 ++12,450 -- -
kursstatistik-api— Secure API with stunnel connection to central course database, secure Dockerfile with ubuntu, ibm_db and running as a non-root user, implementing data validation and transformation. 41 commits:12,208++ 13,526--
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- Developed a secure authentication system using BankID for all students and employees (private repo)
- Created another implementation of BankID with websocket-based client-server communication to listen when the end-user authenticated with BankID:
BankId with websockets- Full-stack solution with React frontend, NodeJS backend, BankID integration, and dynamic QR code generation
Building end-to-end AI solutions with modern tech stacks:
financial-ai-agent— Full-stack financial analysis platform with LangGraph, React frontend, and Python backend. Features competitor research and interactive feedback loops.ai-agent-simple— Complete AI agent system with LangGraph, SQLite persistence, and RESTful API endpoints to OpenAI and Tavily Search.memagent-json— A simple agent implementation with JSON-based memory persistence and API integration with OpenAI (under development)
- Full-stack low-code workflow automation using
n8n,LangChain,Vertex AI,Zapier - End-to-end AI pipeline development and optimization
- Grid optimization systems with real-time monitoring
- Frontend: React, JavaScript, TypeScript, Styled Components, Webpack, Redux
- Backend: Node.js, Express/Koa, Python, RESTful APIs, WebSockets
- Database: MongoDB, SQLite, Redis, GraphQL
- DevOps: Docker, CI/CD, Google Cloud, Azure
- AI/ML: LangChain, LangGraph, Vertex AI, Custom AI Agents
- 13+ full-stack repositories contributed to across frontend, backend, and infrastructure
- Multi-year involvement in core systems with significant impact
- Consistent contributor: 2-6 commits/week on core projects
- Cross-functional leadership: Delivering both internal tooling and end-user platforms
- GitHub: lenaar