Available to hire
I am Stefan Wiest, an AI Fullstack Engineer with 15+ years shipping production-grade systems. I blend product sense with engineering to know what to build, not just how. Trained as a designer (B.A. Industrial Design), I partner directly with founders, CPOs, and design teams to translate product vision into shipped features. I own the full arc — from roadmap and UX wireframes through architecture, deployment, and AI reliability.
I design and ship end-to-end AI systems: from RAG and multi-agent orchestration to MLOps and LLM observability. I’m proficient in TypeScript and Python across cloud-native architectures (AWS, Google Cloud). I bring a strong DevOps foundation (Kubernetes, CI/CD, IaC) and a habit of building for reliability. I collaborate with cross-functional teams to deliver AI-powered products that scale.
Skills
Experience Level
Expert
Expert
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Intermediate
Language
German
Fluent
English
Fluent
Work Experience
Interim CTO / Fullstack AI Engineer at Samsa.AI
July 1, 2024 - PresentArchitected and implemented a scalable full-stack AI platform. Designed microservices across AWS, Cloudflare, and Supabase; integrated multiple model endpoints (Fal, Replicate, HuggingFace); developed an image generation system using Flux with LoRA fine-tuning; built a FastAPI REST API with PyTorch integration; created a Nuxt.js/Vue.js SPA with TypeScript and Tailwind; established a DevOps pipeline with Docker, AWS ECS, and Cloudflare R2; built a cloud-based model migration system using Cloudflare Workers; optimized GPU deployment pipeline with PyTorch compilation and VPN-based secure communication.
Interim CTO / Lead Fullstack Engineer at GrowMetrics
September 1, 2024 - September 16, 2025Led a high-performing team after CTO departure; redesigned product architecture for scalability, security, and extensibility; coordinated external developers; implemented OAuth authentication; streamlined cloud infrastructure to reduce costs and improve resource utilization; tightened access controls, introduced coding standards, and established CI/CD; implemented quality gates and enhanced end-to-end and unit testing.
Enterprise Architect / Principal DevOps Engineer / SRE at StudySmarter
January 1, 2023 - September 16, 2025Led architecture and technology recommendations, balancing business cases and buy/build decisions; provided senior-level guidance to engineers and leads; defined architectural direction, documentation, and best practices; managed migration projects (Bitbucket to GitLab for ~20 repos and ~50 developers); improved monitoring, logging, and PostgreSQL performance; contributed to CRM migration planning and WordPress hardening for security and SRE readiness.
Interim CTO / Startup Advisor at ContainerGrid
March 1, 2022 - September 16, 2025Troubleshot and transitioned company to a professional IT foundation; integrated end-to-end systems with modern architectures; introduced automated testing culture; migrated production from Google Cloud to AWS; standardized SDLC with Kubernetes, GitHub Actions, and Argo CD (GitOps); improved HubSpot tracking and Google Workspace administration; recruited and managed the engineering team.
Startup Advisor / Lead Engineer / Site Reliability Engineer at Peter Park
September 1, 2021 - September 16, 2025Led Agile adoption and improved team velocity (time-boxing, code/design reviews, transparency); mentored on user stories; implemented scaleable user management with role-based access and Auth0 integration; migrated frontend to Vuex-based state management; improved logging with the ELK stack; containerized Python/Java backends; established robust CI/CD pipelines and AWS/GCP hosting; ensured GDPR compliance and data security; supported recruitment and partnerships.
Lead Front-End Manager / Software Engineer at weview
September 1, 2017 - September 16, 2025Built a state-of-the-art front-end system with modular components, DX improvements, linting/testing standards, and a scalable i18n system; enhanced SEO and page rank; delivered a reusable JS widget for product pages; contributed to seed funding and key customer acquisitions.
Lead Front-End Engineer / Full Stack Developer at e-Sixt
January 1, 2017 - September 16, 2025Led frontend engineering for a new SPA in a microservice-aligned stack; built a Golang REST service middleware; contributed to DevOps in a Kubernetes-based environment; established API documentation with Swagger; supported rapid feature releases.
Senior Front-End Manager / Software Engineer at Sixt
June 1, 2016 - September 16, 2025Renewed frontend architecture for the online booking engine; decoupled PHP Smarty templates; introduced API-driven development with Swagger; contributed to microservice transition and improved collaboration across teams; mentored up to 10 developers.
Web Application Developer at zeros+ones
September 1, 2015 - September 16, 2025Developed SPAs with Angular/JS, implemented automated tests, and improved development processes; contributed to SEO-focused frontend improvements.
CMS Developer at zeros+ones
June 1, 2014 - September 16, 2025Managed CMS integrations (Typo3, Wordpress, dotCMS); led front-end and back-end development, including data migrations, API integrations, and documentation; built internal HR management solution with React front-end and REST-based backend.
CTO / Software Architect / Full-Stack Developer at auteon
June 1, 2020 - September 16, 2025Built the first version of auteon using a Buy vs. Build approach; frontend with Vue.js/Vuex; backend with Docker, Node.js, Koa, Python, PostgreSQL, GraphQL; middleware integrations; hosted on AWS/GCP; designed data schema and ETL with Apache NiFi; delivered end-to-end product lifecycle ownership.
Lead IT / Software Architect / Interim CTO / Mentor / Admin at 71circles
October 1, 2018 - September 16, 2025Led IT operations for coworking/innovation pod; introduced SCRUM and lean startup principles; built Ferienluchs booking solution architecture; coordinated contractors; implemented governance for Stage-Gate, OKRs, and product validation.
Senior Engineer / Full Stack Developer at Matmatch
January 1, 2018 - September 16, 2025Led frontend architecture and UI quality for a materials database; migrated data from science team to production-ready schemas; collaborated with CPO/Art Director; delivered SEO-friendly pages and robust API usage; supported large-scale data integration and multi-tenant deployment.
CTO — Gen AI Engineer at Samsa.AI
July 1, 2024 - December 1, 2025Partnered with the CEO to define product roadmap and AI feature priorities, architected a production-grade AI/ML platform, and built a multi-agent ModelTrainer using LangGraph and DSPy for automated LoRA fine-tuning. Implemented LLM observability with LangFuse/OpenLIT, and delivered a scalable FastAPI backend with PyTorch integration and a Next.js frontend. Reduced latency by 40% via optimized GPU deployment and VPN-based communications. Migrated models to Cloudflare R2 with parallel processing.
Interim CTO — Lead Full-Stack Engineer at GrowMetrics
April 1, 2023 - September 1, 2024Led technical strategy after CTO departure, coordinated internal team and external partners, and delivered CI/CD automation. Replaced a monolithic API with modular GraphQL services, implemented OAuth with RBAC, and achieved cost optimizations in AWS.
Principal DevOps Engineer — SRE at StudySmarter
January 1, 2022 - March 1, 2023Streamlined SDLC with GitLab CI/CD, migrated from legacy PHP monolith to Django microservices, improved PostgreSQL performance, and built Elasticsearch-based full-text search for 2M+ items. Collaborated with product/design to drive migrations and establish monitoring.
Interim CTO — Startup Advisor at ContainerGrid
October 1, 2021 - March 1, 2022Defined IoT product strategy, migrated to AWS with Kubernetes, implemented GitHub Actions CI/CD, and introduced Agile practices. Refactored Flask app into microservices and established automated testing with Jest/Nightwatch.
Lead Engineer — SRE at Peter Park
January 1, 2020 - September 1, 2021Implemented Agile practices, migrated AWS infrastructure to ECS/ECR with VPC security, reduced cloud costs, and built a design system to unify frontend components for 50+ developers. Established central logging and GDPR-compliant user management.
CTO — Software Architect — Full-Stack Developer at auteon
January 1, 2019 - June 1, 2020Built production-ready architecture enabling seven-figure seed funding, scaled to 400 active users with Vue.js frontend and Node.js/Koa backend. Implemented GraphQL API and hybrid cloud infrastructure with deployment pipelines and high availability.
Head of IT — Software Architect — Interim CTO — Mentor at 71circles
April 1, 2018 - December 1, 2018Established innovation funnel and Stage-Gate process with OKRs; delivered MVPs for portfolio companies; provided technical leadership on app development, UX, and CI/CD strategies.
Senior Engineer — Full-Stack Developer — FE Architect at Matmatch
October 1, 2017 - March 1, 2018Led frontend development for materials search; migrated to modern frontend stack; improved SEO and performance with SSR; collaborated with design/product on UX iterations.
Lead Front-End Software Engineer at weview
April 1, 2017 - September 1, 2017Established Agile frontend infrastructure, built scalable i18n system, and delivered interactive video editor and embeddable widget contributing to fundraising and customer growth.
Technical Lead at Sixt ride
July 1, 2016 - March 1, 2017Led microservices migration, drastically reduced API surface, optimized cloud spend, and established CI/CD, code reviews, and on-call rotations in coordination with product and design.
Senior Front-End Manager — Software Engineer at Sixt
October 1, 2015 - June 1, 2016Modernized frontend standards, established design systems, migrated build pipelines, and documented 80+ templates to improve maintainability and scalability.
Web Application Developer at zeros+ones
July 1, 2014 - September 1, 2015Led SPA development for enterprise-scale clients; built scalable frontend with Angular, d3.js visualizations, and server-side rendering for performance.
CMS Developer at zeros+ones
October 1, 2013 - June 1, 2014Architected in-house HR management system with React frontend and REST API; established frontend/backend development standards and security measures.
Founder at Karlsthor Development
April 1, 2010 - March 1, 2013Founded technology and design consulting firm; led end-to-end product development for multiple patented products; provided strategic technical advisory to startups.
Project Manager at Strascheg Center for Entrepreneurship
January 1, 2009 - March 1, 2010Built internal entrepreneurial platform, managed founder events, and supported startups with brainstorming, business planning, and process optimization.
Education
Bachelor's degree at Munich University of Applied Sciences
January 11, 2030 - September 16, 2025B.A. Industrial Design at University of Applied Sciences Munich
January 11, 2030 - February 21, 2026Qualifications
Certified Content Management Developer
January 11, 2030 - September 16, 2025Industry Experience
Software & Internet, Media & Entertainment, Education, Professional Services, Other
Skills
Experience Level
Expert
Expert
Expert
Expert
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Intermediate
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