Karat interview. Includes some problems of complexity and a coding problem with DFS + backtracking. I think the interviewer is not concerned about whether your answer is correct; they just record your answer.
The following metrics were computed from 47 interview experiences for the Duolingo Software Engineer role in United States.
Duolingo's interview process for their Software Engineer roles in the United States is extremely selective, failing the vast majority of engineers.
Candidates reported having very good feelings for Duolingo's Software Engineer interview process in United States.