Scale AI's FDE interview: two HackerRank rounds, a broken codebase to debug, and communication graded in every round

FDE Times has published a preparation guide for the Forward Deployed Engineer interview at Scale AI. Drawing on Aced (formerly Exponent), Final Round AI and techinterview.org, it says the process opens with two HackerRank rounds, one of them an online assessment of about 50 to 60 minutes built around a single, hard, project-style coding question rather than a classic algorithm puzzle. The virtual onsite reportedly has four to five rounds: two coding, one system design, one debugging and one behavioural round focused on Scale's values of ownership and moving fast.

The round the guide singles out is debugging: candidates get a codebase they have never seen, a failing test or a described symptom, and about 45 minutes to find and fix the problem. There is no separate communication round, because communication is assessed in every round, so the guide's main advice is to think out loud, reproduce the bug with a small input, and say where any unfixed bug is and how you would test for it if time runs out.

The guide stresses that these descriptions come from candidate accounts and third-party sites, not from Scale, so round order, timing and the roughly two-month timeline should be treated as approximate. Its point is that the rounds track the actual job described in Scale's GenAI FDE posting: rapid iteration on customer needs and explaining technical problems to both technical and non-technical people.

For FDE candidates, the takeaway is to practise taking over someone else's code and narrating your reasoning, not just grinding LeetCode. That is the same skill a customer needs to see when their system breaks.