What NFRs would you identify for a globally scalable, accessible service?

WHAT THIS TESTS: This question evaluates whether you can translate ambiguous product language into concrete, architecturally significant non-functional requirements before any code is written. Senior engineers are expected to hear global and accessibility and immediately think about latency, data sovereignty, compliance, and operational topology rather than just user-facing features.

A GOOD ANSWER COVERS: First, global scale considerations which include latency targets for users on different continents, a multi-region deployment strategy with automated failover and intelligent traffic routing, data residency and sovereignty laws such as GDPR, and horizontal scalability patterns that avoid single points of failure. Second, accessibility considerations which include WCAG compliance levels, internationalization and localization pipelines, support for assistive technologies, and inclusive API design such as semantic markup and keyboard navigation paths. Third, prioritization and trade-offs which means ranking NFRs by user impact, regulatory risk, and infrastructure cost, and clearly identifying which are launch blockers versus fast-follow items. Fourth, cross-cutting concerns including observability across regions, disaster recovery objectives with explicit RTO and RPO, and cost modeling for multi-region infrastructure.

COMMON WRONG ANSWERS: Treating NFRs as afterthoughts that will be handled after the MVP is built. Listing only generic monitoring, logging, and alerting without connecting them to global topology or accessibility standards. Conflating functional requirements like a translation dropdown with non-functional architectural constraints like i18n plumbing and locale-aware data formats. Proposing a single-region architecture with a vague plan to go global later without acknowledging the expensive rework. Ignoring compliance and legal constraints entirely or assuming they are purely legal team concerns.

LIKELY FOLLOW-UPS: How would you prioritize these NFRs if the CEO wants to launch in two months. Which of these requirements would fundamentally change your choice of database or cloud provider. How do you measure accessibility compliance in a CI pipeline. What is your strategy for data residency when a user travels across borders. How do you balance cost against five nines availability.

ONE CONCRETE EXAMPLE: If the service is a video platform, global scale means edge caching with targets under two hundred milliseconds time to first byte, multi-region active-active encoding pipelines, and storing EU user metadata in EU regions only. Accessibility means WCAG two point one AA compliance, captions and audio descriptions, keyboard-navigable players, and localized subtitle pipelines. The architect would reject a single-region monolith because data residency and latency NFRs are architecturally significant and must shape the system architecture from day one rather than being retrofitted later.