Learn how to build and scale a D2C e-commerce platform to handle a 20x volume increase without code rewrites while maintaining 100ms latency goals. This talk covers the architectural decisions, open-source infrastructure, cloud deployment strategies, and observability practices that enabled a high-performance, cost-efficient, and scalable system. Agenda: 1.High-Level Architecture Overview • Micro services for Customer, Catalog, Order Management, Payment and Inventory, fronted by API Gateway • Use of protobuf for lightweight messaging • Sync messages turned to async and back with deferred result 2.Core Infrastructure Advanced Open Source db like Postgres and using its features extensively • Partitioning • FTS • Advisory Locks • Use of bytea type to store read models, and entire protobuf messages – usage similar to NoSql db • Favor inserting new records over updating existing rows. Kafka Beyond Messaging • Load Balancer and lockless Synchronisation • Service Messages vs Service Event topic organization Distributed Caching • Caffeine Cache and JGroups Cloud Deployment: Kubernetes • Low cost scale and cloud agnostic deployment support • Running on credits as part of various startup programs of cloud providers 3.Observability and Debugging • Ensuring correctness with idempotent request handling. • Distributed tracing for debugging cross-service interactions. • Proactive monitoring • All exceptions logged to Slack and actively monitored by team. • Reports and Business Metrics also posted to Slack • Slf4j Slack Appender/Prometheus/Griffin/Sentry ensure you are on top of all the things happening in your system 4.Conclusion and Q&A