Went through the ServiceNow frontend engineer interview in March 2026. Mid-level role on the Now Platform UI team. Sharing the whole thing because I couldn't find much specific to frontend going in.
Full disclosure: I did not get the offer. But I got to the final round and got a debrief, so I know where I fell short.
The Stack They Care About
ServiceNow's main platform UI is built on a custom component framework they call Now Components (basically their own web components layer). You're not expected to know it before joining but they do want to see that you understand web components concepts generally. I didn't know this going in and it came up in the design round. Know at least what custom elements and shadow DOM are.
They also use Angular in some parts of the platform (legacy) and newer work is moving toward React. The frontend screen asked React questions, not Angular, so that seems to be where the energy is.
The Technical Phone Screen
45 min. Two parts: a React component-building exercise (implement a data table with sorting and filtering, live coding on codesandbox), then a series of questions about browser fundamentals. The browser questions surprised me: event loop, how the browser handles paint vs. layout, accessibility tree basics. Not just 'do you know React hooks,' they want to see you understand what's happening underneath.
The Onsite (Virtual) Frontend Rounds
Four rounds. The coding round had one algorithmic question (array, not hard) and one UI implementation: build a search-as-you-type input with debouncing, connecting to a mock API they provided. That one mattered a lot.
The system design round was a frontend system design specifically: design the data table component at scale. How do you handle 10k rows, what about virtualization, how does it work with a server-side filtering API. I've never had this specific flavor of system design before. Practice it.
Where I Fell Short
The debrief was honest, which I appreciated. They said my React fundamentals were strong but my answer on the component architecture question got too implementation-focused too fast without stepping back to understand requirements first. Fair point. I rushed.
Comp I Saw Posted
JD listed $145k-$175k for mid-level frontend. Bay Area numbers. Felt inline with where the market is in 2026 for this level.