Multiple stages:
1) Brief conversation with in-house recruiter
2) Take home go programming exercise ( ~ 3 hours)
3) Three topical technical interviews with different engineers
4) Brief conversation with CTO/CEO.
Overall I thought the interview process was quite nice. The questions asked were practical and useful, and most definitely not the usual whiteboard insanity that is so popular at so many companies.
The interviewers were all knowledgeable and had high levels of empathy during the interviews.