MongoDB Product Design interview questions

Lengthy Interview: - HR Round (phone call) - 2 video interviews - 6.5 hours long onsite interview which includes a design challenge also They ask for portfolio review at each stage

Phone screen with a recruiter then about four hours of interviews a few weeks later including a casual team chat, some breaks, portfolio review walkthrough and a call with one of the heads of product. Everyone was extremely friendly and I truly enjoyed our conversations.