The interview process varies a bit depending on which role/level you're applying for. Software engineering roles will have several phone screen/technical interviews before a virtual "on site" day. The on site will have a few different interview types.
I applied through an employee referral. I interviewed at Duolingo (New York, NY) in Apr 2026
Interview
Had a recruiter call and then technical screening. Coding question was a standard preorder tree traversal questions. There were some followup questions about how to make the algorithm more optimal