Went through the Amex frontend engineer process about two months ago, targeting their digital servicing team (the web app cardmembers use to manage their accounts). Sharing because frontend-specific Amex info is basically nonexistent online.
My background: React/TypeScript, 4 years, mid-level. No fintech experience.
Process was four rounds:
Technical phone screen: JavaScript fundamentals and one coding problem. They asked me to explain the event loop. Not "explain concurrency" in the abstract, literally: what is the call stack, what is the task queue, what is the microtask queue. Then a small coding problem on HackerRank. Mine was DOM manipulation, not React-specific, which I didn't expect.
Frontend-specific technical round: This is where it got interesting. They had a take-home style problem but we went through it live. Build a simple transaction history table with filtering and pagination, no framework allowed (vanilla JS). I normally work in React exclusively and this genuinely tripped me up. I got through it but it was slower than I wanted. Lesson: if you're a framework-only dev, do some vanilla JS warmup before Amex interviews.
Accessibility and performance round: I did not expect this round to exist. They asked me about WCAG 2.1 AA compliance (they serve a broad user base including people with disabilities, this is serious for them), how I'd approach a Lighthouse performance audit, and when I'd use code splitting vs. lazy loading vs. preloading. If you haven't done real accessibility work, read up. They asked specific questions about ARIA roles and keyboard navigation, not just color contrast.
Behavioral: STAR format. The question I fumbled was "tell me about a time you had to push back on a design decision that would have hurt usability." Have a real story, not a vague one.
I got an offer. Base was around $145k for mid-level in NYC. No equity, standard Amex.
The a11y focus was a pleasant surprise honestly. Nice to interview somewhere that actually cares about that.