Implement search by function signature for the purpose of IDE autocompletion. It had to take care of variadic functions. The best answer was using a trie

Design a url shortener. They focused especially on unique id generation and database modeling.

Design system like Feedly

Implement a scheduler in your language of choice. Theyll dive deep into concurrency. I choose java and they basically had me reinvent timer task using primitives like locks, wait, notify etc.

Behavioral round - typical. some discussion about past work, how i felt about certain technology choices, motivation for considering confluent etc

Got an offer but by this point, I had already accepted another offer so did not take.