I design systems starting from constraints and the shape of the load, not from technology. I look at boundaries of responsibility, data flow, failure points, scaling, and the trade-offs between consistency, availability and operational complexity.
System Design, Distributed Systems, Scalability, High Availability, Fault Tolerance, Load Balancing, Caching, Queues, Event-Driven Architecture, Microservices, Modular Monolith, API Design, Consistency, CAP, Idempotency