Amazon Senior Software Engineer interview questions

First an HR rep contacted me with an hour personal interview. Then followed by a 1 hour technical interview (data structures, HashMaps, access times). There was a coding session.

I faced two separate rounds of technical interviews. Both the interviews required building a large scale web application, mainly focusing on the back-end design and architecture. The constraints were that the system needed to be scalable and always available. 1. Build a travel deals web application, where travel agents around the world publish deals, and users can select, pay and avail a deal. 2. Build a distributed calender and corresponding meeting scheduling application.