Went through Affirm's coding process in Q1 2026 while employed. Taking notes because I couldn't find recent info when I was prepping.
The OA (HackerRank) Two problems, 90 minutes. Both were medium difficulty, one leaning toward medium-hard. No hard leetcodes in mine. The first was a string manipulation problem with some edge cases around Unicode. The second was a graph traversal with a twist in the problem statement that you had to read carefully. Time was tight but manageable if you don't over-engineer.
No behavioral questions in the OA. Just coding.
The onsite coding rounds Two rounds in the onsite. Same general feel as the OA: medium difficulty, but the interviewer is watching how you think. They care about: Clarifying requirements before coding (I missed an edge case on the first pass because I didn't ask) Talking through your approach before typing Testing your own code. One interviewer actually said "walk me through what happens with an empty input" mid-solution
The problems were Python-friendly. I was asked to code in my preferred language and chose Python. No objections.
What surprised me: no dynamic programming in either round. I had drilled DP for two weeks. What came up instead was more about data structures and careful implementation. A linked list manipulation problem in one round. Very implementation-heavy.
Difficulty summary: LC medium range. If you're comfortable with mediums and can code cleanly under time pressure, you should be fine. Don't stress about hard problems for Affirm specifically.
FYI this is for a backend senior role. Might differ for other roles or levels.