My first contact was with a recruiter. He was a bit disorganized, missing our first phone call due to meeting schedules – a sign of how busy things are at Square. After some chitchat, he scheduled a Skype interview with an engineer.

The Skype interview was fun, actually. Square uses an Evernote-like online wordpad, on which the interviewer and I wrote code. The task was to implement a function from the C standard library, going through several iterations. The interviewer was also a bit disorganized but was thoroughly pleasant and engaged throughout the hour-long process.

The interview went well, and within a few hours, the recruiter contacted me to set up an in-person battery of interviews for the next week.

The in-person interviews took place at the main office in San Francisco, which is thoroughly modern and attractive. A series of six different interviews ensued, with a roughly equal mix of 'discussion' (read: whiteboarding) interviews with pairs of Square employees and pair-programming with single interviewers. The discussions ranged from in-depth explorations of system architecture to sketching out solutions to given problems. There was a pleasant lack of 'academic' challenges in the discussion phases.

The pair programming exercises ranged from academic to practical, but the experience was good. The engineers were pleasant, and I never felt pressured or judged (despite the fact that an interview is, by definition, an exercise in judgment).

After the formal interviews, I was told immediately that an offer would be made. I was introduced to some engineers and had dinner with one. A formal offer was made the following morning.

On the whole, the hiring process was an odd combination of relaxed and rapid. I liked everyone that I met, had interesting discussions and challenges, and the whole process took 12 days – a record in my experience.

Given an architecture, describe possible approaches to minimizing latency and downtime.