Interview was performed completely over email. I requested to be a tutor, and a few days later I was sent an email GradeSlam considered a test of proficiency. It wasn't about knowledge, more geared towards testing communication skills. Personally, I believe the interview process is more geared towards detecting any major red flags, like the background check. The service itself has a rating system for tutors that better measures actual ability. The interview is easy and simple, so it's a job worth applying to if you are a good teacher and want some extra work from home.