Phone screen, two one hour phone interviews with a hiring manager and someone else from the team, a timed excel test, then a gauntlet on site interview with 5 people for 45 minutes each. During the phone interview, I was told that the ability to learn quickly and work independently was the most valued attribute the HM was looking for. The phone interviews consisted of typical behavioral questions. When you are scheduled for on-site, you have to do a 1 hour excel assessment which isn't difficult as long as you are proficient in using more complex formulas like if/or/and, sumif, etc, pivot tables, and can do variance analysis or something similar. Doing it right is not necessarily the most important thing, being able to walk one of the interviewers through your thought process is the most important part.
The in person interviews were regurgitating the same behavioral questions from the phone interview from people who would be on your team, plus 2 people who would not be on your team. My impression is that the two people who would not be on your team are there to play devil's advocate and find reasons you should not be hired. Though I felt I sufficiently answered their questions, I did not use enough of the "buzzword" BS from their leadership principles when answering their questions. One of the interviewers kept emphasizing things like "dive deep" and that other crap.
Additionally, they sometimes ask loaded questions like "tell me about a time that you were unwilling to compromise". Unless you are the head of a company, you have to compromise at some point, that's the nature of not being at the top of the totem pole, but that is at odds with their leadership principles of "have a backbone". So, if you want an offer, it's not good enough to explain your experience and thought process, even if you think you do so in a way that matches up with their leadership principles. You need to actually use those buzzwords in your responses, because that is what they are looking for.
You will likely have to eat lunch with everyone who is also interviewing for your position and there will be the recruiting coordinators in there with you. This is also part of the interview though it doesn't feel like it, they want to see how you interact with everyone. I thought I got along great with everyone and had them laughing during lunch, and I felt I had a good rapport with the people who would be on my team.
It is a very robotic process, and though Amazon acts like it wants a diverse work force they only want that on a superficial level (i.e., they want different races, genders, orientations, etc.). If they really wanted a diverse workforce, they wouldn't have scripted interviews and expect scripted responses. Though I would like to work for Amazon, I would not be willing to go through that interview process again. Even if they think it ends up helping them hire "only the best", it obviously doesn't prevent an incredibly high turnover they experience.
PS, yes you have to sign an NDA, but that doesn't prevent you from talking about your interview. It only prevents you from talking about some internal information that may or may not be revealed to you during the course of your interview, or you might see something on your way to the bathroom on a computer screen, etc. Aka "confidential information". Anyone on here who says they signed an NDA and can't go into more details, if they were offered a job, goes to show how incompetent you can be, or how little critical thinking you need (i.e., can't read and comprehend simple NDA language), and still get offered a job if you do the tap dance with buzzwords they want you to do. The NDA clearly talks about "confidential information" and interview questions do not fit that criteria.