About
Hi, I'm Julien Hery — a fullstack JS/TS developer based in France, with 9+ years of experience building web products.
I've been writing software since 2015, with a career that spans individual contribution, tech lead, and engineering management. That mix shapes how I approach problems: I care as much about team dynamics and sustainable architecture as I do about the code itself.
I'm actively involved in the developer community. For over three years I organised the SFEIR Lunch meetup — 40+ monthly sessions. I've also spoken at internal events (about Mob Programming, React Testing Library, Flutter) and at Devfest Nantes 2024 on Platform Engineering and Backstage (feedbacks here).
This blog is where I write about the things I'm learning, building, and thinking about — mostly TypeScript, frontend architecture, developer tooling, and engineering practice.
Experience highlights
- Purse (2025–2026) — Payment SDK development in a PCI-DSS context. Monorepo architecture with independent versioning, integrating Svelte and Lit for Widget, Headless Checkout, and Secure Fields modes.
- SFEIR / Waykonect (TotalEnergies) (2025) — Front-end development on a fleet management portal (React / Next.js, MaterialUI).
- SFEIR / Adeo (2022–2025) — Tech lead on Leroy Merlin's customer service tooling (React, Svelte, NestJS), then built an Internal Developer Portal on Backstage (React, Express, Kubernetes). Open source contributor to the Backstage project.
- Engineering Manager, SFEIR (2023–2024) — Managed ~10 engineers: career development, annual reviews, goal setting, client interview preparation.
- SFEIR / Decathlon (2019–2022) — Full-stack development across several projects (React, Svelte, Node.js, TypeScript).
- Pingflow (2017–2019) — Full-stack developer on PingView.
Tech stack
- Languages
- TypeScript · JavaScript
- Frontend
- React · Svelte · Vue.js · Lit
- Backend
- NestJS · Node.js
- Styling
- Sass · Tailwind
- Database
- PostgreSQL · Redis
- Infrastructure & Observability
- Docker · Kubernetes · Datadog
- Tooling
- GitHub Actions · Nx · Lerna
Education
SUPINFO International University — 2014–2017