I was contacted by a hiring agency that wanted to talk about a "secret company." Given the customer numbers they mentioned, it was clear the company was Coinbase.

During the interviews, I was asked a fairly easy algorithm/data structure question, which I solved with some string manipulation.

I also had distributed system design questions. The interviewer focused a lot on what would happen if any part of the service failed.

After several weeks without any feedback, I thought I had been rejected. However, out of the blue, they sent me an offer.

When studying the offer, I looked at Reddit and other forums. People seemed to complain a lot about customer service, lost/stolen money, etc. I didn't feel like working for a company with such a bad reputation and ended up accepting another offer.

Standard algorithms and data structure question.

Design a distributed system. It had some relation with Coinbase's business, but it didn't require any knowledge of cryptocurrency or finance.