YAS (Yet Another Shop) is a production-grade, open-source e-commerce platform implemented as a microservices architecture using Java Spring Boot for the backend and Next.js for the frontend (both storefront and admin backoffice). The system is decomposed into ~15 independent microservices (product, cart, order, customer, inventory, payment, promotion, rating, tax, location, media, search, webhook, recommendation, and sample data) that communicate via REST with resilience4j circuit breakers/retries and event-driven patterns using Kafka and Debezium CDC for cross-service data synchronization (e.g., product changes propagate to Elasticsearch for search and PgVector for recommendation). Authentication and authorization are handled via Keycloak with OAuth2/JWT. The architecture includes BFF (Backend For Frontend) gateways using Spring Cloud Gateway and two Next.js frontends. Infrastructure is fully containerized with Docker Compose and Kubernetes Helm charts, with observability via OpenTelemetry, Grafana, Loki, and Tempo. The codebase includes comprehensive unit/integration tests, UI automation tests (Selenium/Cucumber), and CI/CD pipelines per service. While the repository is primarily an application, it incorporates data engineering patterns (CDC, vector embeddings) for the recommendation and search features, giving it a slight hybrid data character. Overall, the code demonstrates solid engineering practices, a well-defined microservice boundary, and several reusable components, though some duplication across services and boilerplate configs exist.