Uber · Primly Community

Uber frontend engineer interview: what they actually tested (not what I expected)

qa_quinn · 4 replies

Completed the Uber frontend engineer interview process in May 2026 for a mid-level SWE role on the Maps & Visualization team. I've done interviews at Lyft, Instacart, and a few Series B companies in the last year so I have something to compare this to.

The biggest surprise: they tested core JavaScript harder than any framework. I prepped heavily for React specifics and got exactly one question that was React-adjacent. Most of it was vanilla JS knowledge.

Round 1 (phone screen): coding problem, implement a rate limiter in JavaScript. Not a frontend problem at all. More of a general programming problem. I got through it but it felt weird.

Onsite Round 1 (UI coding): build a component from scratch. Mine was a paginated list with a search/filter interface. They cared a lot about debouncing the search input and handling edge cases around empty states and error states. No framework, just vanilla JS/DOM. Time pressure was real.

Onsite Round 2 (JavaScript fundamentals): deep questions on closures, the event loop, prototypal inheritance, and how async/await works under the hood. This felt like a senior-level bar even though the role was mid-level. They basically want you to know what the runtime is actually doing.

Onsite Round 3 (systems/design for FE): frontend architecture round. Design a real-time collaborative document editor. Yes, for a frontend role. They want you to think about WebSockets, operational transforms or CRDTs at a conceptual level, and how you'd structure client state. I didn't know CRDT internals deeply and said so; they were okay with that as long as I understood the tradeoffs.

Onsite Round 4 (behavioral): standard STAR. They asked specifically about a time I disagreed with a technical decision and what I did. Seemed like a real priority for them.

Takeaway: if you're targeting Uber frontend in 2026, study JavaScript deeply, not just React. The bar felt more like a general SWE interview with frontend flavor than a frontend specialist interview.

4 replies

ux_uma

The JS fundamentals thing is consistent with what I've heard. Ex-big-tech take: a lot of the major companies realized their frontend teams were hiring people who could use React but didn't actually understand the platform. The pendulum swung back toward fundamentals around 2023-24 and it stuck.

sec_sasha

Did the design round touch on security at all? CSP, XSS mitigations, auth token handling in a SPA? Or purely about state and architecture?

ae_andre

Barely. I mentioned XSS in passing when talking about user-generated content in the collaborative doc and got a nod but no deep follow-up. The focus was really on state management and sync architecture.

mobile_mara

The UI coding round you described is almost identical to the iOS take-home I've seen described for Uber mobile. Build something real, under time pressure, no framework guardrails. They clearly have a consistent philosophy across platform teams.