I recently gave interview for Confluent Staff postiton

Round 1 - DS/Algo - Medium/Hard question find a related to prefix matching find common sentences in multiple files.

Round 2 - DS/Algo + Concurrency Focused - Design a cache similar to LRU but focus was how to handle concurrent reads and writes, locks, etc...

Round 3 - Problem Solving (Concurrency focused) - Design a scheduler which will execute tasks based on their time, fully focused on Concurrency and MultiThreading.

Round 4 - Design - Design a Url Shortner and focus on Databse design which DB to use for scale.

Round 5 - Design - Focus on API design - Design a service like Podcast where you have subscribed to multiple channels and fetch the top N episodes.

Round 6 - Tech deep dive / Cultural Fit - Previous experience and behavioural questions

Round 7 - Hiring Manager - Previous experiences, interests, roles, what I am looking for, gave team intro and all. Looks like interests were not matching.

After all the rounds HR told me I didn't clear Round 5 - and they want to downlevel it to Sr.SDE which I rejected as I already had a better offer from different company for Staff position. But I say interviews were good and interviewers were also nice.