Node.js Health Checks & Readiness Probes in Production

Node.js Health Checks & Readiness Probes in Production Health checks are the difference between a system that fails silently and one that fails safely. In production, your orchestrator — Kubernetes, ECS, or any load balancer — needs a reliable way to ask your application: are you alive, and are you ready to serve traffic? This article covers building production-grade health checks in Node.js, integrating them with Kubernetes probes, checking downstream dependencies properly, and wiring everything into your observability stack. Why Health Checks Matter Without health checks: A pod that's OOM-thrashing keeps receiving traffic A newly deployed instance starts getting requests before its database connections warm up A service with a degraded Redis connection serves stale data silently Rolling deployments fail mid-rollout with no automated recovery With proper health checks, Kubernetes can: Restart unhealthy pods (liveness probe fails → pod killed and restarted) Hold traffic from not-yet-re