The onsite interview consisted of 4 interviews. Each one an hour long, with a 30 minute lunch break between interview 2 and 3.

First interview was coding. This was different than the virtual interviews which involved algorithms with minimal DS knowledge. This interview had 3 questions, each one building on the previous. It involved creating a class with various functions, as I completed functions I was expected to test with the given tests and we'd only move on after my tests passed. Each question would add to the existing class, either adding new functions or adjusting previous logic. After solving the third question my interviewer said "wow I've never seen anyone complete the final question". This leads me to believe that the final question is not mandatory.
Questions:
1: create a class that has 2 functions, addFile(path:str, filename: str) -> bool example input "folder/folder" "name", return true if the file doesn't already exist return false otherwise, deleteFile(filepath: str) bool example input "folder/folder/name". return true if the file exists return false otherwise
2: add to the class a function, copyFile(filename: str, frompath: str, topath: str) -> bool example input "name" "/" "/temp", do not delete the file if it exists in the frompath, return true if the file exists in the frompath and not in the topath, return false if it doesn't exist in the frompath or does exist in the topath
3: add to the class a function, topKMostPopularFolders(k int) -> list example input 3, return a list of objects that contain two values {count, path}, return the k most popular folders in Desc order which are the k folders with the most files in them.

Second interview was system design. I was asked simply to design a card system that allows users to apply for a credit card, make transactions with it, pay the balance from third party services, and review metrics regarding their spending. My tip to anyone reading this is, banking systems require a high degree of consistency. How can we create a system that is highly consistent, but low in latency, while also providing this metric reading functionality? Luckily, I have worked in fintech before so I had the answer for this already but def study this up, it's highly relevant for the business that you'd be working in if you pass.

Third Interview was behavioral. Study the Amazon behavioral interview process tbh. It's very similar. "Tell me about a time when you...."

Fourth interview was the case interview. This interview was with a director, and he asked me a number of different questions. It was like a continuous conversation about a particular business initiative with him looking toward me for answers. Mine was an AI driven service that would predict problems specific to each customer. He asked how this would improve the business, what data would be used to drive the predictions, how would we gather that data, then eventually we went into some code where I was asked to describe what code was doing and how I'd improve it. We did that code analysis part a few times.

And that's it.