Process started with a phone interview from my would-be boss. All pretty standard questions about my background, what made me interested in the job, etc. Ended with a 30-second pitch for hiring yourself.
The next round was an in-person interview at the company hq. It was 4 half-hour interviews with different members of the staff. Everyone was very friendly and nice. The first was a tech guy and asked technical questions, the second was project management, third was the would-be boss, and last was one of the company's founders.
HR told me they would get back to me a few days later and that there was one more round. They got back in two days