Health Check Endpoints

You need health checks for Kubernetes probes, load balancers, or any system that needs to know if your service is actually ready to handle traffic. This implements the classic pattern: lightweight liveness endpoints that just confirm the process is alive, plus readiness checks that verify your database, Redis, and other dependencies are reachable. It includes examples for Express, Spring Boot, and Flask with proper HTTP status codes and response time tracking. The separation between liveness and readiness is critical because you don't want Kubernetes killing your pod just because your database is slow. The implementations cache results briefly to avoid hammering dependencies with every probe request.