Spring Boot Actuator Health Check Format

Spring Boot Actuator Health Format

Spring Boot Actuator is the de facto standard for health endpoints in Java/Spring applications. Understanding its format helps when designing health checks for any framework.

Standard Actuator Response

{
  "status": "UP",
  "components": {
    "db": {
      "status": "UP",
      "details": {
        "database": "PostgreSQL",
        "validationQuery": "isValid()"
      }
    },
    "diskSpace": {
      "status": "UP",
      "details": {
        "total": 107374182400,
        "free": 68719476736,
        "threshold": 10485760,
        "path": "/.",
        "exists": true
      }
    },
    "redis": {
      "status": "UP",
      "details": {
        "version": "7.2.3"
      }
    }
  },
  "groups": ["liveness", "readiness"]
}

Health Groups (Spring Boot 2.3+)

// GET /actuator/health/liveness
{
  "status": "UP"
}

// GET /actuator/health/readiness
{
  "status": "UP",
  "components": {
    "db": { "status": "UP" },
    "redis": { "status": "UP" }
  }
}

Configuration

management:
  endpoint:
    health:
      show-details: when_authorized
      show-components: when_authorized
      group:
        liveness:
          include: livenessState
        readiness:
          include: readinessState,db,redis
  health:
    defaults:
      enabled: true

Show Details Levels

Level	Effect
never	Only status field
when_authorized	Details for authenticated users
always	Full details for everyone

Custom Health Indicators

In Actuator, you implement the HealthIndicator interface for custom checks. Each indicator contributes to the overall status using the same UP/DOWN/OUT_OF_SERVICE/UNKNOWN semantics. This pattern is worth replicating in non-Spring frameworks.