NODE.JS GUIDE
Node.js Production Debugging
By the HireReadyAI team · 9 min read
An incident playbook covering metrics, memory leaks, pool waits and safe remediation.
Incident mindset
Production debugging starts with stabilizing the patient: reduce impact, then find root cause. Interviewers like candidates who mention rollback, feature flags, and customer communication — not only clever breakpoints.
Signals to check
- Error rate and which endpoint changed
- Event-loop delay and CPU
- DB pool wait and slow queries
- Dependency latency (Redis, HTTP clients)
- Recent deploys and config changes
Memory and leaks
Rising heap across deploys suggests retained references: unbounded caches, global arrays, lingering event listeners, or closures holding large buffers. Capture heap snapshots in staging with a repro; compare retained size of suspects.
Playbook
Reproduce → narrow with metrics → form a hypothesis → test safely → fix with a regression test → add an alert so the next incident is faster. That narrative is a strong senior interview answer.