Informational phone call.

A few days later, a 45-minute technical Skype interview (using Coderpad.io) took place.

A week or so after that, I had five onsite interviews, each lasting 45 minutes to 1 hour. These covered various topics, including the technical implementation of a system, API design (and partial implementation), and previous experience designing systems. I appreciated the interview focus on designing good interfaces.

Before the interview, I was provided with a "How to do well in a Square Interview" document. It accurately represented the experience I had during the interview, with no surprises.

I had lunch at a nearby restaurant with a couple of employees to break up the long onsite interview process.

Technical questions focused more on programming practices than algorithm implementation.