I don't remember how I applied, but remember that Amazon contacted me by email. First step was an informal interview with one of the team members, followed by 5 formal interviews. What's the difference between formal and informal? I didn't quite understand. The interviewers were nice, tasks were well formulated with some exceptions. Mostly trivial algorithms. For all questions involving algorithms I first implemented the task using the most-trivial, least-efficient method, told the interviewer the current complexity and then incrementally improved the algorithm for efficiency. I'd recommend you the same as it gives you the time to analyse the task and have some basis for improvement. Didn't solve 2 tasks and was asked to send the solutions immediately after the interview. And I sent. After a week I got a phone call telling me about an offer.