The process started of with 3 phone interviews with the hiring manager, a senior program manager and a senior engineer. The interviews were heavily geared towards technical questions around Operating Systems (virtual memory, busy waiting, context switching etc.), Algorithms, Data Structures and SQL Server internals.
After having done well in these interviews I was flown over to Seattle for on-site interviews. I had 5 1-on-1 interviews with engineers on the team. Each interview typically required me to whiteboard a programming problem and/or a mathematical puzzle. There was also some questions around SDLC, unit testing etc.