Flash Sale

Multi-Language Edition: This chapter is also available in Vietnamese at 📖 Bản tiếng Việt (Vietnamese Edition). Previous Chapter: Chapter 1 — Microservices Foundation | Series Hub | Next Chapter: Chapter 3 — Traffic Shield: Kafka Peak Shaving Answer-First: Shopee prevents inventory overselling during high-concurrency flash sales by combining local memory caching, Redis inventory sub-key sharding, and atomic Lua script decrements. This multi-tier architecture isolates hot keys in Redis memory shards and evaluates stock availability in sub-milliseconds without acquiring relational database locks. Adopting this pattern guarantees sub-10ms P99 latency bounds, zero-allocation memory optimization, and mathematically verified zero overselling across hundreds of thousands of concurrent checkouts. ...

Multi-Language Edition: This Masterclass is also published in Vietnamese at 📖 Bản tiếng Việt (Vietnamese Edition). Answer-First: The Shopee Architecture series details how Go microservices, Redis Lua inventory reservation, Apache Kafka peak shaving, TiDB distributed SQL, and OpenTelemetry/ClickHouse observability handle 10M+ QPS and millions of concurrent buyers during 11.11 flash sales without overselling or database connection starvation. Masterclass Overview: The Southeast Asian E-Commerce Engine Shopee is the leading e-commerce platform in Southeast Asia and Taiwan, operating across Singapore, Indonesia, Vietnam, Thailand, Philippines, and Malaysia. During annual shopping festivals (9.9, 11.11, 12.12), platform traffic surges by more than 10x within seconds at midnight, creating catastrophic load spikes that break traditional web architectures. ...

Flash Sale Architecture: Rate Limiting & Redis Answer-first: High-concurrency flash sale systems absorb millions of synchronized user requests using a 5-Tier Traffic Shedding Architecture: Cloudflare CDN edge static asset caching, Envoy API Gateway atomic Token Bucket rate limiting, Redis Cluster Lua inventory reservations with hotkey slot splitting, partitioned Kafka queue buffering, and asynchronous Go worker pools executing batch upserts into TiDB/MySQL. [!NOTE] On sourcing: This article describes flash-sale architecture patterns for C10M-scale events; it is not a disclosure of Shopee’s internal systems, and the figures here are engineering targets rather than published Shopee metrics. Shopee has not publicly documented its flash-sale internals in detail. What is public is its database platform choice — Shopee’s adoption of TiDB is documented in PingCAP’s case studies (How Shopee Chose the Right Database, Shopping on Shopee, the TiDB Way). Treat everything else as a reference pattern to validate against your own workload. ...