The problem
The existing e-commerce platform was losing approximately 1,000 orders per month due to recurring technical failures: checkout errors, an unstable payment gateway, and inventory race conditions during peak traffic. Estimated business loss was around EUR 100,000/month in revenue, on top of reputational damage and the increased load on customer support.
The approach
- Audit of the checkout flow with log analysis and session replay to localize the actual failure points instead of acting on assumptions.
- Rebuild of the checkout with a simpler, more resilient architecture, reducing single points of failure and isolating the payment gateway behind a circuit breaker.
- Refactor of inventory concurrency handling to prevent oversell and double-booking during peak traffic.
- Coordination of a cross-functional team of 6-10 engineers (frontend, backend, DevOps) running three parallel client projects on the same engineering bar.
- Introduction of structured code review and shared architecture guidelines, so that incidents on one project would not silently regress on another.
The result
- Approximately 1,000 orders/month recovered against the pre-intervention baseline.
- Approximately EUR 100,000/month of additional revenue for the client.
- Drastic reduction in checkout-related customer support escalations.
- Engineering quality bar standardized across the three concurrent projects, with measurable benefits on lead time and incident frequency.
The rebuild paid for itself well inside the first quarter, and the patterns introduced (resilience around third-party gateways, inventory concurrency control, shared review practice) outlived the original engagement.