Portfolio — Sergkei Kournosenkov
Energy sector: streamlined bid management system
ECS GmbH · energy sector client · 2021 – 2026 · Role: Frontend developer · migration lead
Built core features (complex, adjustable questionnaire templates, versioning, sync between multiple external systems) that automate and accelerate the bid process, and led the migration from Angular 15 to 22 while development continued.
Problem: I joined a year after the MVP. The platform needed complex new features, and its stack (Angular 15, Bootstrap 3) had fallen far behind while the project was still under heavy development.
Approach: Implemented complex, adjustable templates for questionnaires, a merging and diff system with versioning, a compare feature for complex multi-level structures, and sync between multiple external systems to automate the bid process. Planned and documented the upgrade from Angular 15 to 22 and Bootstrap 3 to 5 in detail, and guided and mentored team members who were new to modern Angular (new control flow, signals).
Result: Migrated the whole system (150K lines of code) across seven Angular major versions and from Bootstrap 3 to 5 with no feature freeze, and brought the team up to speed on modern Angular.
Stack: Angular 15 → 22, TypeScript, Signals, Bootstrap 3 → 5
paidopsy-trikala.gr: custom WordPress site
Freelance · paidopsy-trikala.gr · 2019 · Role: Designer · developer · hosting
Designed and built a completely custom WordPress theme, and set up hosting, domain and email end to end.
Problem: A completely new practice with no web presence. This was its first website.
Approach: Designed the site and built a completely custom WordPress theme. Set up the whole infrastructure: hosting, domain, DNS and email.
Result: Lighthouse (desktop): 98 Performance, 96 Accessibility, 100 Best Practices, 100 SEO.
Stack: WordPress, Custom theme, PHP, Hosting, DNS & Email · Live site
Nuvé Apartment: holiday apartment showcase
Freelance · Nuvé Apartment · 2026 · Role: Design · development
Showcase site built from scratch with AI-assisted design. The visibility it created led to a nearly 100% occupancy rate.
Problem: A holiday apartment without its own web presence needed visibility to attract guests.
Approach: Created the site from scratch, using AI-assisted design to move quickly from concept to a finished showcase.
Result: Nearly 100% occupancy, driven by the visibility the site created.
Stack: AI-assisted design, Vercel, Responsive, Multilingual
nonomo.de: from intern to shop relaunch
Nonomella GmbH · nonomo.de · 2016 – 2019 · Role: Intern → lead developer → Head of IT
Three stages: started as an intern, led frontend and backend on the first upgrade, then the full overhaul with a custom configurator and a modern, responsive design.
Approach: 2016: joined as an intern on the existing shop. Autumn 2016: first upgrade, as the main frontend and backend developer. 2019: as Head of IT, the complete overhaul with a custom product configurator and a modern, fully responsive design.
Stack: JTL Shop, PHP, Smarty, MySQL, Responsive
fidella.org: purchase advisor & modernisation
Nonomella GmbH · fidella.org · 2016 – 2019 · Role: Head of IT · lead developer
Built an interactive purchase advisor and modernised the shop.
Approach: Implemented a purchase advisor that guides customers to the right product, and modernised the shop design.
Stack: JTL Shop, PHP, JavaScript, Responsive
← Back to website
English · Deutsch · Ελληνικά
Printable CV · llms-full.txt · Privacy