About William
👋 Hi, I'm an AI-Powered Full-Stack Engineer helping startups and FinTech companies build intelligent digital products that solve real business problems.
I specialize in developing 𝐚𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬, 𝐦𝐨𝐛𝐢𝐥𝐞 𝐚𝐩𝐩𝐬, automation systems, and scalable backend solutions.
Whether you're validating a 𝐬𝐭𝐚𝐫𝐭𝐮𝐩 𝐢𝐝𝐞𝐚, launching an 𝐌𝐕𝐏, integrating 𝐀𝐈 into your business, building a 𝐅𝐢𝐧𝐓𝐞𝐜𝐡 𝐩𝐫𝐨𝐝𝐮𝐜𝐭, or scaling an existing platform, I can help transform your vision into a production-ready solution.
---------------- 𝘾𝙖𝙨𝙚 𝙎𝙩𝙪𝙙𝙞𝙚𝙨 & 𝙄𝙢𝙥𝙖𝙘𝙩 -----------------
- AI SaaS Launch: Built a complete web/mobile solution (backend, AI, payments) for a startup, driving quick validation.
- FinTech Automation: Delivered secure application architecture and intelligent automation, reducing manual work.
--------------------- 𝙒𝙝𝙖𝙩 𝙄 𝘽𝙪𝙞𝙡𝙙 ------------------------
- AI & Automation: LLM/OpenAI integration, AI agents, chatbots, workflows, and automated document processing.
- SaaS & Startups: End-to-end MVPs, subscription billing (Stripe), dashboards, and product scaling.
- FinTech & Security: Secure financial apps, transaction workflows, RBAC, and compliant data protection.
- Web & Mobile: Responsive web apps and cross-platform mobile solutions (iOS/Android).
--------------- 𝙄𝙣𝙙𝙪𝙨𝙩𝙧𝙮 𝙒𝙝𝙖𝙩 𝙄 𝙘𝙖𝙣 𝙬𝙤𝙧𝙠 ------------------
Startups, SaaS, FinTech, AI-First & Growing Tech Companies.
💬 Whether you need an AI Engineer, Full-Stack Developer, SaaS Developer, or MVP Expert , let's discuss your project!
English
Native or bilingual
Can work on-site
Berlin (up to 50km)
Experience
- Mid-Tier U.S. Technology CompanySenior Full-Stack AI & Automation DeveloperJanuary 2021 - January 2025 (4 years)- Designed and delivered AI-powered automation systems that reduced manualworkload by 70%+ and improved operational efficiency 2–5x.- Built and deployed enterprise-grade LLM systems, including RAG pipelines,document-AI tools, and multi-agent workflow assistants.- Developed full-stack platforms using React, Next.js, Node.js, and Typescript,supporting high-traffic operations with 99.9% uptime.- Engineered automation workflows using n8n, Make, webhooks, and serverlessfunctions, optimizing internal and client-facing processes.- Created custom AI chatbots and assistants that reduced support costs by 40% and accelerated response times.- Architected secure and scalable backend APIs, integrating with payment providers,CRMs, ERPs, and various third-party services.- Collaboration with cross-functional teams to define system requirements, buildproduct roadmaps, and ship high-impact releases.
- European Software Solutions FirmFull-Stack Developer (AI + Web Systems)January 2019 - January 2021 (2 years)- Developed and maintained web applications using React, Node.js, and PostgreSQL for SaaS and internal business tools.- Implemented automation workflows using early n8n/Make integrations to reduce data entry and manual reporting tasks.- Collaborated with senior engineers to architect backend APIs and streamlinedatabase performance.- Improved front-end UI/UX and optimized application performance for faster load times and smoother user flows.- Supported several client deployments and contributed to documentation, testing, and code quality improvements
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Education
- Bachelor of EngineeringTechnical University of Berlin2018Bachelor of Engineering
- Warsaw University of Technology2018