The interview had 3 phases, the first conversation with the CEO / founder, a technical interview with the other founder, and a conversation with the client.
The technical interview was the best one I've ever done, not based on LeetCode, but on open questions and the interviewer pushed to really deep concepts, to the point that we reached a few technical concepts I had no idea about, but we kept discussing as if we were building those low-level concepts from the scratch, such as creating a SQL DB from the ground-up.
When I was approved in this interview I was proud, as I understood that this type of interview is not what people are prepared to normally, and I have a feeling that engineers that just write CRUD applications would fail on it, as many only know high-level usage of tools / frameworks, and not the concepts underneath them.
The conversation with the client was quick and mostly aimed at knowing each other and the challenge, given I'd be working together with the client's CEO into building the application and managing the team.