Specialist applicants have rated the interview process at PEAK6 with 3 out of 5 (where 5 is the highest level of difficulty) and assessed their interview experience as 100% positive. To compare, the company-average is 46% positive. This is according to Glassdoor user ratings.
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The whole thing was straight forward, standard, and upfront. If I remember correctly there were three rounds and all were pretty quick (30 min). No out of the blue questions either.