• High concurrency and scalability patterns

• Strong knowledge of:

• System trade-offs (consistency vs availability, latency vs throughput)

• API design and service boundaries

• Fault tolerance and resilience design

• Experience with system decomposition and domain modelling

• Expert-level proficiency in Java (8/11/17+)

• Strong experience with Spring Boot / Spring Cloud

• Deep understanding of RESTful APIs and microservices

• Experience with ORM frameworks (Hibernate, JPA)

Frontend

• Strong hands-on experience with at least one:

• Solid understanding of frontend architecture and state management

• Ability to contribute to frontend system design (not just coding)

Data & Infrastructure

• Strong experience with relational databases (Oracle / SQL Server / PostgreSQL)

• Experience with:

• Redis or distributed caching...