Applied online and had a response within 3 business days. Was pushed straight from application to onsite interview (I go to a target school, may have been a factor). Onsite was scheduled for the following week. Received a call confirming my offer and the offer letter in 4 business days after the interview.
Interview is extremely well laid out for candidates. You know exactly what type of questions you'll be asked going in. There are three types: Job Fit (technical), Behavioral, and Case.
Job Fit: Typical leetcode easy-medium questions. Pretty soft compared to the questions you'll receive at any Big4 company. I won't be sharing the exact questions below because this review is being posted in the middle of interview season, but I had 3 questions, one involving OO Design, one on Linked Lists, and one on Dynamic Programming.
Behavioral: Standard behavioral interview. Use the SAR method and make sure to take your time, you'll get asked three "Tell me about a time..." style questions and have a full 45 minutes.
Case: This one was new to me but just do some research on the kind of things they'll be looking for with these questions. Mine was pretty heavy on the math but I was able to reason my way through most problems and do the calculations afterwards. It really is a good test of logical thinking; if you have the skills for it you could do this with no practice (but you should practice).
All the interviewers are really friendly people. I had about 10 minutes to spare with each of them and was able to ask some great questions to each.
The onsite process with C1 itself is great, as was the whole interview process. Looking forward to working there next year.