Spring Boot Actuator

This handles the operational side of Spring Boot services: health checks, metrics endpoints, and secure management ports using Actuator and Micrometer. You'll reach for it when setting up readiness probes for Kubernetes, exposing Prometheus metrics, or isolating management traffic on a separate port with proper authentication. The skill covers the full progression from basic health endpoints to custom health indicators and dedicated security chains using EndpointRequest matchers. One thing worth noting is the emphasis on keeping sensitive endpoints like /env and /heapdump locked down, which is easy to overlook when you're just trying to get observability working. The reference materials include endpoint catalogs and examples for different export targets, so you're not hunting through Spring docs during an incident.