I was referred by an employee and had a short screening call with a recruiter to discuss the different locations and teams.

After that, I was invited for an onsite visit where I met with two people for approximately 45 minutes each. It was all technical, covering expected topics for an SE (data structures, computational complexity, etc.) with whiteboard coding.

This went well enough, but I ended up withdrawing my candidacy for another opportunity.

Fast forward a couple of years, Google reached out to me, and the timing was better. I was invited for another onsite (technically the second in the process; I think my first still 'counted') and met with five to six engineers for approximately 45 minutes each. It was basically a longer version of the first visit, with a similar style (lots of coding, design, etc.).

Standard CS topics, lots of data structures and solving toy problems.