Guillaume Gelin
Engineering Lead
Salaire / Taux journalier
Paris, France
Freelance, ouvert au CDI
Peut venir sur site
Expertises
Langues
Expérience de travail
Freelance Software Engineer
Self-employed
déc. 2020 - Présent
5 ans 11 mois
Proven expert in software architecture and platform engineering, I help startups and scaleups to build high-end services, with a strong focus on business KPIs, scalability, and developer experience.
Co-Founder & CTO
Refty
août 2021 - août 2023
2 ans 1 mois
Paris, France
I used to be a "peacetime" manager and engineer. Then I learned the hard way to trim the feedback loop from 5 weeks to 5 days. We designed and deployed a recruitment automation technology through which thousands of candidates have passed, used by clients such as Ubisoft, Decathlon, Castorama, or Lydia. We raised 600 K€, recruited a team of 10, reached up to 50 K€ monthly revenues, but eventually ran out of cash after many pivots. → Entrepreneurship, Figma, FastAPI, TypeScript, Pulumi, React, and shipping an insane amount of things
Numberly (1000mercis Group)
juin 2014 - nov. 2020
6 ans 6 mois
Paris, France
Principal Engineer
août 2018 - nov. 2020
2 ans 4 mois
Paris, France
Numberly is a 70 M€+ revenue publicly-traded marketing technology company made of 400+ employees selling all kinds of data marketing products and services to large companies such as Danone, Lacoste, Allianz, Sofinco, etc. Hands-off work: • Conducted software engineering matters at the tech committee, responsible for the roadmap and organization of our 150+ developers. • Provided direct management of the Real-Time Bidding API team and the Media Trading engineering team. Lead the cross-functional backend development efforts as the founder of the "backend guild". • Enhanced our employer brand internally and externally through a number of online and offline initiatives, which allowed us to double the size of our tech team over my time here. Recruited and mentored engineers at all levels (junior, senior, lead, and "Head of"). • Increased overall productivity through several major company-wide organizational changes: team reorganizations, new tools, new processes. Hands-on work: • Deployed a multi-tenant Kubernetes cluster running around 1K services (600 CPU, 2.5 TB RAM, bare metal) and onboarded our 150+ developers on this new deployment process. • Designed and implemented a customer data platform used by 20+ key clients, with services deployed in several regions across the globe. • Developed an ad server and its segmentation engine, processing thousands of requests per second from big brands websites. • Migrated 1K+ public domains from authoritative PDNS servers to Amazon Route 53. All these systems are still up and running as of 2024. → Company management, change management, team management, recruitment, cloud-native tech, software architecture, high availability, geo distribution, microservices, DNS arcanes
Lead Software Engineer
juil. 2015 - août 2018
3 ans 2 mois
Paris, France
Software Engineer
juin 2014 - juil. 2015
1 an 2 mois
Paris, France
Formation
EPITECH - European Institute of Technology
Master of Science (MS), Information Technology
2010 - 2015
5 ans 3 mois
Portfolio
Plateforme SaaS événementielle et application WebGL collaborative en temps réel
