Did the frontend eng loop at OpenAI earlier this year. Spoiler: it's mostly a general SWE loop with some frontend flavor, not a pure framework trivia quiz.
What the loop looked like: Recruiter screen, one 45-min phone screen (coding), then a 4-hour onsite (3 technical rounds plus one behavioral/values round).
Phone screen: A coding problem. Medium difficulty, data structures. No DOM, no React, just straightforward algorithmic problem. I was kind of surprised. I think they want to confirm coding baseline before spending onsite time.
Onsite round 1 (UI/product coding): This was the most frontend-specific round. I implemented a small interactive component from scratch. Vanilla JS or framework of my choice. They cared about state management, edge cases, accessibility considerations. Not a trick, just build a thing and explain your decisions. No TypeScript required but I used it and it was fine.
Onsite round 2 (algorithms/coding): Another coding round. Two problems. One on arrays, one more graph-flavored. Medium difficulty. I think they weight this because they want FE engineers who can work on performance-critical code, not just wire up components.
Onsite round 3 (system design, frontend-ish): Design a real-time collaborative text editor or something in that space. Not a full system design like a backend senior would do, but I needed to think about state sync, websockets, optimistic updates, conflict resolution. Know what CRDTs are at a conceptual level even if you haven't implemented one.
Values round: Same as what others report. Genuine discussion about AI safety and responsible product decisions. Don't treat it as a formality.
One thing I'll say: the product they're building is unlike any other frontend job. If you're a React dev who wants to build dashboards and marketing pages, this probably isn't the fit. If you want to work on novel AI interfaces where no one has figured out the UX yet, there's nowhere more interesting right now.
Comp for mid-senior FE in SF: competitive with top of market, probably slightly behind backend SWE at same level but not dramatically.