Java

Tell about your work experience: what you did, what was interesting, what team you were part of.

Auth Service is in a gap between API and Transaction Service — if it fails, everything collapses. How did you secure this?

Why is Postgres needed if you send events to Kafka? How does the client receive the result?

What is a high-load system? What were the real load figures in your project?

How have you worked with multithreading? Were there interesting cases with race conditions or deadlocks?

Why did you need Redis if you have Postgres?

How was the infrastructure organized? Tell me more about Kubernetes, Docker, CI/CD.

What is ELK? Decode the abbreviation and explain the purpose of each component.

Why did you use Kafka instead of simply accepting a request and processing it synchronously? Why not scale the instances?

Tell me about optimistic locking: in what cases is it used, what problems can arise, and why not pessimistic?

Tell me about the system architecture: how does a request go from the client to processing, and what infrastructure was used?

Why did you use Spring Web for API Gateway instead of ready-made proxy solutions like Nginx, Envoy?