Start with a phone interview about basic information, like why you apply Roblox, when will you available to work. Then two online is coding questions, not that difficult.
Interview questions [1]
Question 1
Two strings, find the first intersected character?
the process is HR interview -> Coding Challenge -> technician interview. They were both very nice. But the interview question is not about algorithms. The interviewee are requires to find bugs from the codes.
I applied online. The process took 3 weeks. I interviewed at Roblox (San Mateo, CA) in Nov 2017
Interview
Asking basic information through the phone, why do you apply that position, do you played their games or editor, what kind of knowledge do you have. Two technical questions online within two hours.