SOLID Principles, OOP Principles, Microservices - Pros and Cons, AWS Services, DB questions - ACID, CAP theorem, Primary Key, Foreign Key, Indexes, Types of Joins, Denormalization, Go and Java specific questions - inheritance, concurrency, locks. Web - RESTful API, REST methods, idempotency, n+1 problem. Design patterns - Singleton, Factory, Builder, Chain of responsibility Second interview - http, dns, cdn, cache, load balancers, cache, reverse proxy.