Provide expert full stack leadership, defining patterns and enabling delivery across React/Redux front ends, Java/Spring Boot and Python microservices, and secure REST APIs (Java, Spring, Node, serverless), while enforcing secure by design practices and mentoring engineers to apply them consistently. Non functional engineering leadership designing for scalability, reliability, performance, and availability, including load shedding, autoscaling, partitioning, caching, and high availability/failover pattern.