Scaling E-Commerce Infrastructure for Millions

Solving high-concurrency checkout race conditions, distributed inventory locks, real-time fraud scoring, and global edge CDN caching.

Traffic that arrives evenly is a solved problem. This course is about the other kind: a launch, a sale, or a link that lands somewhere large, where a checkout that worked yesterday starts selling the same unit twice.

Inventory is the central example. Marcus works through optimistic and pessimistic locking, reservation windows and their expiry, and the point at which a single row becomes the bottleneck for the whole catalogue. The race conditions are demonstrated under load rather than described, which makes the fixes easier to justify.

Payment and fraud scoring follow, with an emphasis on staying correct when a provider times out mid-request. The final module covers edge caching for a catalogue that changes throughout the day: what can be cached, what must never be, and how to invalidate without emptying the cache for every region at once.