Fintech & Commerce
Design a Flash Sale System (High concurrency, preventing overselling)
A short-burst, extreme-concurrency purchase system that prevents overselling limited inventory under massive simultaneous demand.
Open and Simulate this Architecture in InfraDraftCore Architectural Components
Pre-Sale Queueing/Waiting Room Service
Smooths a traffic spike into a manageable admission rate.
Atomic Inventory Decrement Service
Redis Lua script or row-level DB locking guaranteeing no two buyers claim the same unit.
Rate Limiter
Caps purchase attempts per user to blunt bot-driven demand.
Order Reservation with TTL
Holds a unit for a short window while payment completes, then releases it.
Distributed Lock Service
Coordinates the oversell-prevention check across concurrent requests.
Payment Timeout & Inventory Release Worker
Frees held inventory if checkout doesn't complete in time.
Traffic Shedding/Load Shielding Layer
Protects the backend from being overwhelmed at the moment the sale opens.