I came from a pure-FAANG background so I underestimated the behavioral portion at Block. Went into onsite thinking the technical rounds were the hard part. The behavioral round is no joke. They take culture fit seriously in a way that caught me off guard.
Block's stated values around 'purpose-driven' and 'customer obsession' aren't just wall art. The behavioral questions directly probe whether you've actually operated that way or are just saying the words.
Questions I was asked across two behavioral rounds (one with a peer, one with a hiring manager): Tell me about a time you disagreed with a product decision and what you did about it. Describe a project where you had to make a technical decision with incomplete data. How did you decide and what happened? Tell me about a customer problem you cared about personally, not just because it was assigned to you. How have you handled a situation where a teammate wasn't meeting expectations? Walk me through a time when you had to prioritize ruthlessly under a tight deadline.
The 'customer problem you cared about personally' one is the most Block-specific in my opinion. They care a lot about economic empowerment, serving underbanked customers, that mission-driven stuff. You don't have to be evangelical about it but you do need a genuine story about caring about end users.
Tips that helped me: Keep your STAR answers under 3 minutes. They will ask follow-ups so leave room. Name the actual impact metric, not 'it improved things significantly.' Give them a number. For disagreement questions: show you voiced it clearly, gave it a fair shot, then committed to the outcome. They don't want martyrs or yes-people.
I got an offer in the end. The behavioral prep took me longer than the leetcode prep. Don't skip it.