I want to push back on the common prep advice for Affirm behavioral interviews, which is mostly "prepare STAR stories and you're fine."
Yes, you need STAR stories. But Affirm's behavioral round has a specific flavor that's easy to miss if you're just pattern-matching to generic "tell me about a conflict" questions.
Their values tilt fintech-specific. Affirm has a strong "financial honesty" narrative baked into their brand. In my experience the behavioral questions probe for: Situations where you had to be honest about bad news (to a stakeholder, your team, a customer) even when it was uncomfortable Times you pushed back on a decision you thought was wrong Examples of making something simpler when there was pressure to add complexity
That last one surprised me. The interviewer asked me about a time I removed a feature or simplified a design. "Honest, simple, and transparent" is literally in their public values language, and they apparently mean it.
The cross-functional question is almost guaranteed. Something like "tell me about a time you worked with a team outside engineering to solve a problem." At a fintech like Affirm, eng touches risk, compliance, merchant relations, and customer ops. If you only have eng-to-eng stories, you're going to feel the gap.
What doesn't land: Generic stories about "leadership" that are really just "I wrote a doc and sent it to stakeholders." They push back. My interviewer asked three follow-up questions on one of my stories until she got to something that felt real. Plan for depth, not breadth.
The format in my loop was one dedicated behavioral round, 45 minutes, with one interviewer. Behavioral questions were also sprinkled into the system design round opener ("tell me about a recent project").
One more thing: they ask about failures. Not as a gotcha but they genuinely want a real failure, not "I worked too hard." Have something real.