Senior React/Next.js hires should improve velocity, not just write components. Use this guide to probe depth across architecture, performance, product sense, and release rigor. Every prompt below ties to enterprise outcomes: faster MVP development sprints, reliable launches, and measurable wins from performance audits for web apps. If you want pre-vetted talent and delivery muscle, slashdev.io can staff elite remote engineers and full-stack teams.

• Architecture: Use the App Router with Server Components where data density is high; pick SSR, SSG, or ISR per route; define module boundaries and caching policies early.
• Performance: Run Lighthouse, WebPageTest, and React Profiler; enforce Core Web Vitals budgets; prioritize route-level code splitting, image optimization, and critical CSS.
• Product delivery: Drive MVP development sprints with small, testable increments; de-risk unknowns first; wire telemetry to prove value within each sprint.
• Release management: Harden CI/CD with preview environments, feature flags, canaries, and rollbacks; cover app store deployment and release management for React Native or PWAs when applicable.
• Security and DX: Solid auth, secret handling, dependency hygiene, reproducible builds, and a fast test suite to keep throughput high.

• Server vs Client Components: Given a dashboard with real-time filters and heavy data joins, where do you place logic? Describe trade-offs, hydration cost, and caching.
• Data fetching strategy: For a product page with price, inventory, and reviews, pick SSR, SSG, or ISR and justify revalidation timings and fallback UX.
• Performance audits for web apps: Outline your audit checklist, tooling, and how you convert findings into backlog items with KPIs and ownership.
• State management: Compare React Query, SWR, and server actions for data; explain where a global store still adds value and how you avoid prop drilling.
• Accessibility and i18n: Show me patterns for focus management in modals, keyboard navigation, and locale-aware formatting with dynamic routes.
• Release discipline: Describe your branching model, CI gates, and how you design feature flags and safe rollbacks for multi-tenant Next.js apps.
• Product instincts: In a two-week MVP sprint for onboarding, what is your thin slice, and how do you cut scope without hurting UX?

Assign a focused, 6-8 hour project with a public repo and a short Loom walkthrough. The brief: build a catalog search experience in Next.js App Router that hits a rate-limited API and supports saved filters.

• Data and components: Results render as Server Components; filters are Client Components; mutations use server actions; cache and revalidate correctly.
• Fetching mode: Pick SSR, SSG, or ISR per route; document the choice and show skeletons and error boundaries.
• Performance: Set budgets for LCP, INP, and CLS; run Lighthouse and React Profiler; deliver a brief report and a prioritized fix list.
• Feature safety: Implement a feature flag and an A/B variant; ensure clean rollbacks and telemetry coverage.
• Quality bar: Add e2e tests with Playwright, unit tests for utilities, and type-safe external API handling.
• Resilience: Handle rate limits and API failures with retries, exponential backoff, and user-visible recovery paths.
• Delivery: Treat the work like two MVP development sprints; share a changelog, a backlog triage, and a cut-scope rationale.
• Optional mobile: Export as a PWA and outline app store deployment and release management if ported to React Native, including build lanes and phased rollout.

Score on signals that predict success at scale, not polish alone.

• Architecture fit: Clear boundaries, minimal client JavaScript, and correct use of streaming, caching, and parallel routes.
• Measured speed: Shows before/after numbers from the audit, ties them to Core Web Vitals, and links fixes to customer impact.
• Delivery chops: Evidence of slicing, risk burn-down, and explicit trade-offs in scope to keep momentum.
• Release craft: Thoughtful CI gates, feature flag hygiene, and a rollback story your ops team will trust.
• Communication: Crisp README and Loom explaining why decisions map to business goals and timelines.

• Implement an accessible modal with focus trapping, keyboard handling, and ARIA labeling; add tests.
• Sketch multi-region caching with the Edge Runtime, stale-while-revalidate, and route segment config.

Beyond correct answers, seniors exhibit business fluency and ownership.

• They translate architecture into KPIs, forecast impact, and make trade-offs explicit for stakeholders.
• They operationalize quality with scripts, CI checks, and dashboards, not slideware.
• They design for constraints-rate limits, data privacy, budgets-and keep the roadmap unblocked.
• They mentor through code reviews, examples, and documentation that raises the team’s floor.

Bake these steps into your process and you will consistently hire seniors who ship outcomes, not overhead. Calibrate once, then reuse the rubric for speed, fairness, and signal. Pair it with disciplined release notes and quarterly performance audits for web apps, and your Next.js platform will compound.