Freelancer profile translated to English.
Back to original languageAbout Billy
Software engineer and full-stack architect with over 15 years of experience**, I specialize in **Spring Bootbackend development andJavaScript/TypeScriptfrontend (EmberJS, Vue, React…), with a strong background in software architecture and technical leadership.
I co-founded and developedSoyoutrip(intelligent travel planner) from scratch at Fragmnt.io — from idea to architecture, backend to frontend, through to production. Since 2022 until July 2026, I held the role of **CTO at Teelt.io**, a SaaS onboarding solution, where I led all technical decisions and achievements.
More recently, I have specialized inintegrating LLMs into production**: **local modelson NVIDIA GPUs / Apple M Chips withqLoRAfine-tuning, andcloud LLMs via API(Mistral, Anthropic…). These skills are at the core ofWellington**, my conversational AI application that embeds its own **custom LLM Local model, trained and optimizedfor each conversation.
Need an autonomous senior developer, capable of leading a project from design to deployment? **I am available**.
French
Native or bilingual
English
Fluent
Can work on-site
Châteauroux (up to 50km), Tours (up to 50km), Blois (up to 50km), Orléans (up to 50km), Paris (up to 50km)
Experience
- Hello Wellington (hellowellington.app)Lead Developer / Indie DeveloperSOFTWARE PUBLISHINGJanuary 2026 - March 2026 (2 months)Châteauroux, FranceWellington — Conversational AI Mobile App (iOS & Android)Solo design and developmentof a mobile application allowing users to interact with fully customizable AI personas, powered by fine-tuned language models.Product & BusinessFreemium modelfree access with one persona and a daily message quota, premium offer unlocking multiple personas, unlimited messages, and personalized fine-tuning. Integrated monetization via RevenueCat for unified iOS and Android subscription management.Tech StackFlutter mobile frontend (iOS & Android), Java Spring Boot backend API, MariaDB database. Automated deployment via Fastlane with certificate management and App Store/Google Play Store publication.InfrastructureEPYC dedicated server with 128 GB RAM under Proxmox, secured by an OPNsense firewall with Suricata IDS/IPS. Production VMs scale in an isolated DMZ. Gitea CI/CD pipeline with dedicated runners. HAProxy reverse proxy with Let's Encrypt SSL termination. Dedicated GPU servers for LLM operations and fine-tuning.Skills UsedCloud-native architecture, LLM & fine-tuning, DevOps & CI/CD, Network security, Cross-platform mobile development, Monetization & App Stores
- TeeltFull Stack Engineer (Frontend, Backend), NodeHUMAN RESOURCESOctober 2018 - Today (7 years and 9 months)Bastia, FranceTeelt.io is precisely the kind of startup I can help. They had the idea but lacked in-house expertise to develop their web platform. My associate and I therefore supported this startup from the design phase to launch. Once the needs were gathered, we defined a roadmap in collaboration with the company, taking their budget into account. This was followed by technological choices, design, development, and finally the deployment of their brand-new web platform on a robust and secure environment. We now work with them regularly based on their needs in short sprints to integrate new features.Since 2022, I have been acting as CTO for Teelt.ioTechnologies: NodeJS, EmberJS, Virtualization
- SoyoutripCo-FounderTRAVEL AND TOURISMAugust 2018 - February 2022 (3 years and 5 months)Soyoutrip offers an innovative service in the travel sector. Equipped with an engine to generate itineraries for visiting cities, Soyoutrip provides a schedule composed of the destination's must-see activities. It optimizes travel by selecting activities that are close to each other. It brings the necessary intelligence between entertainment quality and minimum travel time. The schedule is, of course, fully modifiable so that the traveler can delete, move, or add new activities they prefer.Finally, Soyoutrip is not just an innovative website, but also an Android mobile application that allows users to access their itinerary on the go, and have the necessary information and services at their fingertips to reach their activities.- API integrations with various services.- Design, architecture, and development of the website- Design, architecture, and development of an internal monitoring and administration dashboard.- Design and development of the Soyoutrip Android mobile application- Design and implementation of the technical infrastructure on dedicated servers with virtualization.
Recommendations
These freelancer profiles also match your criteria
Agatha Frydrych
Backend Java Software Engineer
4.7
(3)
2
Baptiste Duhen
Fullstack developer
4.6
(4)
5
Amed Hamou
Senior Lead Developer
4
(2)
7
Audrey Champion
Web developer
4.3
(3)
4
Education
- Computer Engineering DegreePolytechnic School of the University of Nice Sophia Antipolis2008Spécialité Systèmes Temps Réels Embarqués et Applications Mobiles