Went through the PANW frontend interview for their XSOAR UI team (enterprise security orchestration product). Sharing because the frontend loop at a security company has some quirks you won't see at a typical product company.
What the role is This is a React-heavy role on a really complex, data-dense enterprise UI. Think incident timelines, alert correlation views, graph visualizations of attack paths. Not a marketing site or simple CRUD app. They want engineers who can reason about performance, state management, and accessibility in a very noisy data environment.
Loop structure Recruiter screen, then a 4-round onsite: React + JavaScript fundamentals UI system design Behavioral Hiring manager conversation
Round 1: React + JS They started with vanilla JavaScript questions: prototype chain, event delegation, closure, Promise chaining. Then moved to React: explain re-render behavior, how does useCallback actually help (or not), when do you reach for useReducer vs useState. There was a live coding component: build a searchable/filterable table component from scratch. No design system allowed, just plain React.
The filter question had a gotcha: what happens to performance when you have 10,000 rows? They wanted virtualization, specifically knew about react-window/react-virtual. If you haven't touched list virtualization, study it.
Round 2: UI system design Design an alert triage dashboard. Users need to see 500+ real-time alerts sorted by severity, filter by category, drill into details, and bulk-acknowledge. I walked through state management approach (server state via React Query vs local state), websocket integration for real-time updates, optimistic updates for the bulk-ack action, and keyboard accessibility. They pushed hard on the keyboard accessibility part. Security ops teams use keyboard shortcuts constantly.
Round 3: Behavioral PANW asks about cross-functional collaboration. Strongest question: tell me about a time design and engineering fundamentally disagreed on implementation. How did you resolve it and what was the outcome?
Comp Senior FE, Bay Area: $200k total, base $148k. 2026 offer.