Instacart · Primly Community

Instacart frontend engineer interview: what they focus on and what surprised me

frontend_fran · 4 replies

wrapped up the Instacart frontend engineer interview loop a few weeks ago. went in expecting a fairly standard frontend screen but there were some surprises. sharing notes for anyone about to go through it.

the setup: recruiter call, technical phone screen, then a 4-round virtual onsite.

technical phone screen: one coding question, javascript, done in coderpad. they gave me a problem involving DOM manipulation and event handling. not react-specific. i remember thinking "oh they want to see if I actually understand the platform, not just the framework." i'd say medium difficulty, focused on correctness and explaining trade-offs.

virtual onsite:

coding round 1: more javascript. array/string manipulation, medium difficulty. the interviewer was hands-on and asked me to refactor my solution partway through once it worked. they wanted to see how i think about readability and performance, not just green tests.

coding round 2: this one was more frontend-specific. they gave a design requirement and asked me to implement a small UI component in react. they cared about: accessibility (aria attributes, keyboard nav), error states, and edge cases. not about pixel-perfect styling.

system design (frontend): this was scoped to frontend architecture, not backend distributed systems. they asked something like: design the Instacart search experience at a high level. think about: state management, API design from the client's perspective, how you'd handle loading states and partial failures, how you'd approach performance for a product catalog with thousands of items. this round was the most interesting.

behavioral: 4-5 STAR questions. the one that tripped me up was about a time i disagreed with a technical direction and how i handled it. have something specific, not vague.

overall impressions: they seemed to genuinely care about craft. my interviewer in the component round asked me follow-up questions about my opinions on CSS-in-JS vs utility classes. it felt like a real conversation about how i think about frontend, not a checklist.

bay area role, mid-senior level target. offer would have been in the L4/L5 band based on what the recruiter said earlier. didn't make it past debrief (no specific feedback given, which is frustrating) but the process felt fair.

4 replies

market_realist

the frontend system design round is something companies don't talk about enough. too many frontend interviews are just "implement this component" and never check if you can think at the architecture level. sounds like instacart gets it.

veteran_vance

quick question: did they test on any specific react patterns or was it general javascript-first? asking because I've been heavy on vanilla JS from my last project.

frontend_fran

the component round was react but honestly the concepts matter more than the syntax. if you know hooks, the mental model for state/props, and can reason about when things re-render, you'll be fine. I wouldn't worry about memorizing specific API signatures.

apm_aisha

the part about the CSS-in-JS vs utility classes question is funny to me. would have loved to be a fly on the wall for that conversation. tailwind vs styled-components is basically religion at this point.