Couchbase visited our campus for placements. Their shortlisting process was quite different from other companies — it was based primarily on the candidate's resume and CGPA, not on any preliminary DSA coding test. The first and only round I appeared for focused heavily on system-level concepts. Since I was interviewing for a Server Developer position, the discussion centred on low-level system design, object-oriented programming, and operating systems. One major problem I was asked to solve was designing a Producer-Consumer system similar to AWS SQS. I had to implement the solution in Java and parallelize the logic using multithreading. Following that, I was asked theoretical questions around memory management, paging (including concepts like page faults and thrashing), and rate limiting mechanisms. The conversation went deep into core systems knowledge, so preparation in OS and concurrent programming is key.