APIs and Microservices: RESTful, GraphQL, OpenAPI specifications, API gateways and management, microservices and event-driven architecture, service mesh, asynchronous messaging (e.g., Kafka), API security (OAuth 2.0, OIDC, JWT), and exposing AI models and agents as reusable, scalable services. • Agentic AI: Agent loop design (ReAct and planner–executor patterns), agent harness engineering, multi-agent orchestration, tool calling and Model Context Protocol, memory and state management, human-in-the-loop controls, and agent evaluation and observability (e.g., OpenTelemetry tracing).