Did my BCG frontend engineer loop earlier this year. Background: 4 years of React experience, mostly working in design systems and component libraries. I expected a pretty standard frontend loop. I was wrong about some parts of it.
The role was for their internal products team, building tools used by their consultants. That context matters for what they asked.
Technical round 1: live coding (60 min) Two problems. First was a React component exercise: build a filterable data table with pagination from a mock API response. They cared about: how I handled loading states, how I thought about component decomposition, whether I reached for unnecessary libraries or kept it lean. Second problem was a pure JavaScript question about event handling and closures. Not tricky, but they wanted to see that I understood the language, not just the framework.
Technical round 2: architecture / design (45 min) This was more interesting. They described a dashboard that would be used by 20 consultants on a client site, needed to work with spotty internet, and had to surface real-time data updates. I walked through my approach: service worker + cache strategy for offline support, websocket vs polling trade-offs, state management choices. They pushed back a few times, which I liked. Felt like a real technical conversation.
The case round (yes, frontend engineers get it too) Mine was shorter than what I've seen described for DS or EM loops, about 30 minutes. The scenario involved a client considering a digital product investment and I needed to help structure the analysis. I won't pretend I nailed it. I leaned on my PM experience from past collaboration and tried to think out loud. They seemed fine with imperfect, they wanted to see reasoning.
Behavioral fit round Four behavioral questions in about 50 minutes. A time I disagreed with a design decision and how I handled it, how I collaborate with designers (relevant given the role), a time I had to explain a technical constraint to a non-technical stakeholder, and a project I'm most proud of.
I got an offer. Total process was 6 weeks. Comp for the senior frontend role in a major metro came out to around $155k base plus bonus, which is below top-of-market FAANG but the bonus structure and learning environment made it compelling for where I am right now.