https://mhassan.dev/categories/backend/Recent content in Backend on Muhammad Hassan RazaHugoen-USFri, 25 Sep 2026 10:00:00 +0500https://mhassan.dev/blog/war-stories-from-production/Wed, 08 Apr 2026 10:00:00 +0500https://mhassan.dev/blog/war-stories-from-production/Two cashiers selling the last item, a chain that returned nothing, and a lock that only worked when both requests hit the same process. Bugs I shipped, and the unexciting fixes that held.https://mhassan.dev/blog/optimizing-django-performance/Mon, 10 Feb 2025 10:00:00 +0500https://mhassan.dev/blog/optimizing-django-performance/Refunds that queried once per line item, stock updated one row at a time, and signals that recalculated ledgers nobody asked about. What I changed in Polaris, and what I'd tell myself earlier.