Berkay Turk

Multi-tenant B2B SaaS marketplace connecting France's largest construction companies (Vinci, Bouygues Construction, Loxam) with equipment rental providers; 1,000–2,000 active users.

• • Architected end-to-end a two-sided quote negotiation system enabling 4 major construction clients to request equipment and receive competing offers from multiple rental providers, with counter-offers and full negotiation tracking. Owned database schema, PostgreSQL migrations, FastAPI endpoints, and performance optimization.

• • Reduced a critical API endpoint response time from 3,000ms to 250ms (12x improvement) via index tuning, N+1 query elimination, and raw SQL where ORM was the botleneck.

• • Maintained and evolved 100+ RESTful API endpoints in FastAPI: request validation, dependency injection, background tasks, async endpoints. Engineered PostgreSQL schemas and optimized queries, indexes, and joins for production workloads.

• • Worked within a multi-tenant SaaS architecture, ensuring data isolation, scoped queries, and secure access paterns across enterprise clients (Vinci, Bouygues Construction, Loxam).

• • Implemented OAuth2 and JWT authentication and authorization flows for secure access control across services.

• • Containerized services with Docker, automated infrastructure tasks with Bash scripts, and authored unit/integration tests with Pytest, sustaining ~90% test coverage to minimize regression risk.

• • Partnered closely with frontend developers and product stakeholders to translate product requirements into reliable backend solutions.

GAP — Geodis Automation Platform: internal web platform automating 20–25 IT infrastructure operations for 200–250 internal users.

• • Engineered a Python/Django web platform to automate IT infrastructure operations via centralized web interface; delivered both backend logic and frontend components (HTML/CSS/JavaScript/jQuery).

• • Architected backend logic to trigger, monitor, and manage automation workflows, integrating infrastructure-level actions into user-facing applications used by 200+ IT operators.

• • Partnered with DevOps teams using Ansible playbooks; gained working knowledge of infrastructure automation tooling. Operated in Agile (JIRA) and maintained technical documentation in Confluence.

Contributed to petabyte-scale scientific computing infrastructure (4–8 PB datalake) for the ESCAPE project and CERN's Rucio data management system, serving 100+ international researchers.

• • Contributed to development and maintenance of large-scale data storage systems supporting a 4–8 PB scientific datalake (Rucio); authored Jupyter Notebooks for scientists' data access and analysis needs.

• • Deployed Kubernetes clusters for research and data-processing workloads; configured JupyterHub on Kubernetes, enabling scalable notebook environments for 100+ scientists.

• • Created and maintained Docker containers tailored to ESCAPE project needs; participated in CI/CD pipelines (GitLab) to automate build and deployment for containerized services.