My interview experience with Square was amazing! Although a lengthy process, I believe that it is efficient to find the right candidates and getting to know them properly. Every applicant is assigned a "recruiter" based in San Francisco, who is you main point of contact through out the whole interview experience. My process was as follows:
1. Recruiter Interview
Was a <30 minute call with your allocated recruiter. General questions were asked including what you know about the role and your general working experience
2. 1.5 hour interview with 3 Square staff members
I thought this was going to be a daunting interview since I was told that it will be a 1.5-2 hour interview. However, the interview was super casual and allowed the staff to get to know me properly. Each staff member spoke to me separately (30 minutes each) and asked me general questions with a practical exercise (nothing too difficult).
Sometimes there will be a third interview with the "top" hiring manager in San Francisco, however I did not have to complete this step. I was offered a role 2 weeks after my 3 stage interview. Overall, the process took 1 month from applying to offer being made.