The process started when one of their recruiters reached out to me on LinkedIn. I spoke with her for about 30 minutes. I was told that the total process would be 5-6 interviews (including the initial recruiter screen) over about 2 months, including at least one on site interview at their office in NC.
Next I spoke with an engineering manager. It was a pretty high level, general tech interview. The only in depth technical question was related to how I would design a REST API for a search function. They were interested in being VERY specific, ie what would go in the query string, route url, etc.
The 3rd interview was a one hour 1:1 zoom. The first question was about the criteria I would use to decide which 3rd party library/package I would include in a project. Next came the coding challenge. I was given 30 minutes to complete a recursive function for a simulated board game. They used some online IDE that didn't support debugging, only printing to the console. I did not complete the challenge in 30 minutes and so failed the interview. I explained my thought process and the interviewer said I was on the right track and with more time would have gotten it.
After this interview the recruiter I was working with went dark. She did not respond to any emails and about a week later I got a generic rejection letter about 'not being the right fit'.
I really don't like that more and more companies are using these contrived problems in an unrealistic time as elimination challenges in their interviews, but that's the world we live in now.