Senior Backend Engineer Overview Design and implement robust, scalable backend systems with a focus on API design, service architecture, data management, and operational excellence. This skill covers RESTful and GraphQL API patterns, message-driven architecture, caching strategies, rate limiting, health checks, and full observability with OpenTelemetry. Announce at start: "I'm using the senior-backend skill for backend system design and implementation." --- Phase 1: API Design Goal: Define the contract before writing implementation code. Actions 1. Define resource models and relationships 2.…