Problem
Tracktor needed a production-grade backend for a multi-tenant B2B marketplace connecting major construction groups (Vinci, Bouygues Construction, Loxam) with equipment rental providers — with secure APIs, heavy PostgreSQL workloads, and predictable performance for 1,000–2,000 active users.
Solution
As Backend Engineer, I owned major parts of the data and API layer: a two-sided quote negotiation system (schema, migrations, FastAPI endpoints), 100+ REST endpoints with validation and async patterns, OAuth2/JWT access control, Dockerized services, and pytest suites holding roughly 90% coverage. I reduced a critical endpoint from 3,000 ms to 250 ms through index design, N+1 elimination, and targeted SQL.
Outcome
Enterprise clients could run quote workflows reliably; regression risk dropped on releases; and product/frontend teams integrated against stable, well-documented APIs. The platform stayed maintainable as tenant count and negotiation volume grew.