Node.js shows up in 48.7% of Stack Overflow survey responses among web frameworks and runtimes—often the API layer behind React or mobile clients (Stack Overflow 2025 Technology). Hiring managers need signal on async production behavior, not Express tutorial familiarity alone.
These five questions track what full-stack and backend guides emphasize for Node stacks: the event loop, middleware, API contracts, error handling, and operational incidents.
1. “Explain something that blocked the Node event loop on a team you worked on.”
Strong candidates name CPU-heavy work on the main thread, sync filesystem calls, or huge JSON parsing—and how they moved work off-thread or chunked it. Weak answers pretend Node is “non-blocking” for everything.
2. “How do you structure middleware for auth, validation, and logging?”
Listen for ordering, single responsibility, and testability. You learn whether they have maintained a real Express/Fastify/Nest app or only scaffolded demos.
3. “Design an endpoint for creating a resource. What status codes and error shapes do you return?”
API design questions reveal consistency. Good answers cover idempotency where relevant, validation errors vs server errors, and stable JSON error contracts.
4. “How do you handle unhandled promise rejections and process-level failures in production?”
You want global handlers, graceful shutdown, health checks, and alerting—not “we restart PM2 when it crashes.”
5. “Tell me about a production incident in a Node service. What changed afterward?”
Incident stories expose ownership. Strong candidates mention postmortems, timeouts, circuit breakers, or load limits they added.
Turn answers into comparable evidence
Log one event-loop example, one middleware pattern, one API design choice, and one incident follow-up per finalist. Compare outcomes, not framework fanboyism.
One scorecard for every finalist
Use the same five questions for each candidate for this opening. Consistent questions support consistent evaluation, which aligns with EEOC guidance for employers to apply the same standards to applicants for the same position (EEOC).
Use Canvider JobCraft to lock Node and API expectations in the JD, InterviewGen for gap-based follow-ups, and DecisionHelper to compare finalists on the criteria you published.
Next step: Explore InterviewGen and DecisionHelper, then get started free.