I applied online. I interviewed at SpaceX (Los Angeles, CA) in Oct 2016
Interview
They asked a lot of questions about my experience and previous jobs and past projects and how they turned out and some technical questions and also wanted to know how I worked with other people and how I would perform in this environment.
Multiple rounds of interviews ending with an all day onsite interview. Asked questions about background, classic textbook problems, and coworker interactions. Very technical and difficult. Lots of time spent trying to understand your thought process
Rigorous but fairly reasonable in my experience. The technical problems often has a twist but if you have strong fundamentals you should be able to perform well. The recruiter and interviewers I interacted with are all very nice people.
4 rounds, 1 with technical recruiter, 1 with engineer, 1 with manager, and onsite. first 3 are over the phone. onsite was the challenge, consists of presentation, one-on-ones, and tour.