Proven experience designing and running backend architectures at scale: microservices or modular monoliths, event-driven and asynchronous messaging (e.g., Kafka, RabbitMQ, SQS/SNS, Azure Service Bus), and distributed systems patterns. At least one year of hands-on, practical use of modern AI engineering tools (Claude Code, Cursor, Copilot, etc.), with experience integrating AI/LLM capabilities into backend services where relevant (agentic patterns, evals, and latency/cost/reliability tradeoffs).