I was contacted by a US recruiter through LinkedIn (I am living in Europe). She told me I should pass two phone interviews first before the onsite. I passed the two interviews about questions on machine learning and business related to Amazon. Then they invited me to the onsite, I had to present my PhD thesis (1 hour) and then 4 1-1 interviews of 1 hour each with members of the team. The structure is the same, present yourself, questions about the Amazon core values, technical questions (programming on whiteboard) and finally real use cases of the company. In general the interviewers were very nice and I enjoyed the time of the interview. Two days later I got a call from the recruiter telling me that I was in, literally "we would like you to join our team". Then I emailed several times to her asking how was the process going, sometimes she didn't even reply back (I sent at most 1 email a month, I think is not too much). After 9 months I stopped emailing her. I could not imagine why amazon treats candidates like this, in such a lack of respect... I consider the overall experience very bad and would not apply again.