Jonathan Gelin
Developer Experience Architect 路 AI Tooling 路 Nx Expert
馃嚞馃嚙 English 馃嚝馃嚪 French
20+ years in software development, from Java to the JavaScript/TypeScript ecosystem. Now focused on unifying technologies and enabling seamless full-stack development at scale.
I help companies tackle their software development lifecycle challenges through Nx monorepos, micro frontends, robust testing strategies, and AI-augmented tooling. Whether it's optimizing build systems, implementing custom plugins, or introducing architecture-aware AI workflows鈥擨 focus on practical solutions that teams can adopt and maintain.
As passionate about coaching and knowledge sharing as I am about coding. Every day brings new opportunities to learn, share, and grow together.
Julius Baer
Mar 2025 - Present 路 Remote
Partnered with the Software Development Acceleration department to streamline and modernize the Software Development Lifecycle across a large distributed repositories ecosystem. My work focused on introducing a scalable architecture powered by Nx, improving consistency, performance, and developer experience across dozens of heterogeneous codebases, while also bringing AI-assisted tooling into key engineering workflows.
Caseware
Mar 2024 - Feb 2025 路 Remote
Collaborated with the Dev Success Team to maintain and improve a large Central Monorepo (~900 projects) alongside multiple Distributed Monorepos. As an Nx expert, implemented an architecture designed to maximize the benefits of the Nx ecosystem.
Entain
Jun 2023 - Dec 2023 路 Remote
Oversaw the migration of multiple repositories and projects into an Nx monorepo for Entain. Developed the migration strategy, conducted coaching and pairing sessions with developers, configured the CI/CD pipeline, and ensured effective use of tools to uphold best development practices.
Selligent Marketing Cloud
Apr 2020 - Jun 2023 路 Hasselt, Flanders Region, Belgium 路 Remote
Established the new frontend architecture across multiple teams, including coaching/pairing with developers, configuring CI/CD pipelines, and ensuring adherence to best development practices. Migrated a large AngularJS application to a micro-frontend architecture.
Jonathan joined us on a short six-month contract to help plug a gap in our team and tidy up some internal build tooling. Very quickly, it became clear he was having a much bigger impact, and he ended up staying with us for a year. During that time, he reshaped how we think about and work with our tooling from the ground up.
He reworked our build setup into a clean, Nx-based architecture with clear conformance standards, making day-to-day development simpler and more consistent while raising the bar on quality and maintainability. Jonathan also brought strong AI skills to the table, introducing AI carefully and intentionally, only where it genuinely made sense for the team and the product.
On a personal level, Jonathan is enthusiastic about new technology but refreshingly pragmatic and outcome-focused. He is deeply test-driven and helped us put snapshot-based end-to-end testing in place, which massively increased our confidence in releases and noticeably improved the overall developer experience.
If you're a company looking to streamline your tooling, improve engineering standards, and make life easier for your developers, I couldn't recommend Jonathan more highly.
I have had the pleasure to work with Jonathan for around a year, and I can only recommend him for any software development team.
He has the energy and passion, the vision, and technical expertise to drive a team, suggest roadmaps, and implement solutions at an amazing speed and quality. Our project had to manage a wide range of technologies (Maven, Typescript in Node, Jib, Helm, GitLab pipelines, build caching, parallel builds, etc.) and he has been helpful in all aspects.
I am glad I have had the opportunity of working with him, and so will be the engineers of any project he will decide to join in the future.
I had the pleasure of working alongside Jonathan during his time with our team, where he made an invaluable impact as an expert in Nx and Typescript. Jonathan immediately set himself apart by designing a clear and actionable path from our current state to the ideal state of monorepo management. His strategic vision, combined with his ability to communicate complex technical concepts in an understandable way, was a key driver in our team's success.
Jonathan's approach to challenging the status quo was marked by a great deal of empathy and thoroughness. His ability to balance constructive critique with a focus on long-term improvement was invaluable.
His commitment to mentoring developers across the organization and producing extensive documentation played a crucial role in making complex processes accessible to the broader team.
Jonathan is a true professional鈥攈ighly knowledgeable, collaborative, and dedicated to improving the development experience for everyone around him. I wholeheartedly recommend him for any role requiring deep technical expertise and a passion for driving impactful change.
I've had the privilege of collaborating with Jonathan for over two years at our organization, and I am thoroughly impressed by what he was able to achieve as a freelance Frontend Architect. Jonathan was entrusted with the challenge of leading our teams through the migration of a substantial legacy frontend codebase to a modern, state-of-the-art monorepo, employing a micro-frontend architecture utilizing Angular and Nx. This transition was monumental.
By the time of his departure, he had not only revolutionized our frontend development landscape but also equipped us with a solid foundation and the essential knowledge to keep innovating further. It felt to me like he moved a mountain, and it's incredible how much I learned from him.
I highly recommend Jonathan to any organization seeking a visionary in modern frontend solutions.
