About

Hi!

I’m Seb, an engineer based in the French Pyrenees.

Work

I work as a Staff Engineer at RAFIKI / NALA, building financial services and payment infrastructure in Africa for the next billion.

I also lead security and infrastructure efforts, including building custom Vault plugins, handling security audits and penetration tests, and hardening systems that process sensitive payment and KYC data.

I previously served as CTO at Bloomup, spent summers working at Osper, Mendeley, and BlueMind, and consulted for companies in the UK and France.

I’m a full-stack engineer at heart, but these days I focus mostly on backend work. I use Go, Postgres, AWS, Terraform, and Kafka to build reliable, scalable systems. I’ve also worked with Rust, Python, and C++.

Interests

In my free time, I’m usually in the mountains, on the water, or in the air. I love paragliding, kitesurfing, rock climbing, and skydiving. Otherwise, I enjoy learning about robotics, hardware, electronics, and embedded systems, working on side projects, or making pizza.

Contact

Email: contact@graphman.fr
GitHub: github.com/graphman65
Keybase: keybase.io/graphman
LinkedIn: linkedin.com/in/sebastien-lacoste