went through the affirm frontend loop last month, senior/L5 level, sharing because i wish i'd found something like this before going in.
the recruiter screens are pretty standard. she was nice, spent more time on the role than i expected. confirmed team, tech stack (react, typescript, some proprietary stuff for their checkout embed), and asked one light behavioral q before scheduling the technical screen.
technical phone screen: one round with an engineer. coding challenge in a shared editor. i got a DOM manipulation question, nothing crazy, but they wanted clean vanilla JS first, then asked me to refactor into react with hooks. the react piece tripped up a few candidates apparently (recruiter mentioned it). make sure you're comfortable with useEffect and cleanup functions, closures inside hooks, the usual suspects.
onsite (virtual, 4 rounds): react deep dive: we went through component lifecycle, state management patterns, and they asked me to build a small configurable modal from scratch. they watched me name things and structure props. no trick questions, just real craft. system design for frontend: "design the affirm checkout widget for merchant embeds." this was meaty. they care a lot about resilience (what happens when Affirm's JS fails to load?), performance budget, and accessibility. i hadn't prepared accessibility at this depth and it showed. coding (medium LC-style): array manipulation, expected to explain time/space complexity. behavioral: STAR format, about 4 questions. conflict on a team, a time you pushed back on a product decision, ownership of a bug.
things that matter to them: they kept coming back to "what happens when it breaks." affirm's checkout widget is mission-critical for merchants, so resilience thinking is huge. being able to articulate progressive enhancement, fallbacks, and error boundaries went further than clever algorithm tricks.
process was clean. about 3.5 weeks total from phone screen to offer. feedback loop was decent, recruiter updated me twice without me asking.