went through the jane street designer interview process last quarter. this one is hard to find info on because most JS content is SWE/quant. writing this up because it's genuinely different from product designer loops at consumer or b2b SaaS companies.
the role context matters a lot. i was interviewing for a position on an internal tooling team, building interfaces for traders and researchers. your portfolio work doesn't need to be finance-related but the questions they'll ask will filter for whether you can reason about complex, data-dense, high-stakes UIs. if your portfolio is all marketing sites and checkout flows, that's not an automatic disqualifier but you need to bridge to the kind of design thinking they care about.
the portfolio review: 2-3 projects, you drive, about 30-40 minutes. the questions are surprisingly technical: "how did you handle the information hierarchy when the data set was large?" "walk me through the performance constraints and how that affected your design decisions" "how did you involve engineers early in this project?"
there was very little "what was your design process" at a high level. they go straight to the detail. bring a project where you did something hard, not just something pretty.
what they did not ask: user research methods (mentioned, not grilled on) accessibility specifics (light touch) metrics and A/B testing (not relevant given internal tooling context)
the design exercise: given a brief (something like: display live position data for 50 securities across different asset classes), sketch a solution in 45 min and present it. no figma required, whiteboard or paper sketch is fine. they cared about reasoning, information hierarchy decisions, and whether i asked good clarifying questions at the start.
vibe: interviews felt like conversations with people who care a lot about craft but in a precise, functional way. not vibes-y. bring your best "why does this decision make the user faster/safer" energy.
not many design roles open there at any given time so the pipeline is slow. i waited 3 weeks between rounds. ended up not proceeding past final round, they went with someone who had more financial data visualization experience.