Health checks

Feather registers all three on every app, so there’s nothing to write.

Endpoint	Purpose	What it checks
`/health`	Full health check	Database connectivity, app running
`/health/live`	Liveness probe	The process is alive. Always 200 if responding
`/health/ready`	Readiness probe	The app can serve traffic, database connected

Liveness versus readiness

Liveness answers whether the process is alive. A failure here means the container should be restarted. Readiness answers whether it can handle requests. A failure here means stop sending traffic, but do not restart. Consider an app that is running while its database is down. Liveness passes, because the process is alive. Readiness fails, because it cannot serve requests. The load balancer stops routing to that instance until it recovers.

Response format

{
  "status": "healthy",
  "timestamp": "2024-01-15T10:30:00.000Z",
  "checks": {
    "database": "ok"
  }
}

Healthy returns 200 OK. Unhealthy returns 503 Service Unavailable.

Wiring it up

Load balancer
Kubernetes
Docker

For AWS ALB, GCP and similar:

Setting	Value
Health check path	`/health`
Healthy threshold	2
Unhealthy threshold	3
Interval	30 seconds

livenessProbe:
  httpGet:
    path: /health/live
    port: 8000
  initialDelaySeconds: 5
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /health/ready
    port: 8000
  initialDelaySeconds: 5
  periodSeconds: 10

The health endpoints are exempt from the scaffold’s rate limit, so a probe this frequent never earns a 429. See Rate limiting.

The generated Dockerfile already has HEALTHCHECK ... curl /health, and deploy/deploy.sh waits on it before declaring a deploy finished. Most PaaS hosts either detect /health or accept it as a configured health-check path.

Prefer /health to a hand-written route. A container with a broken DATABASE_URL reports unhealthy instead of quietly serving 500s.

Get started

Tutorial: build a Kanban app

Building the UI

Backend

Features

Tooling

Testing

Deployment

Liveness versus readiness

Response format

Wiring it up

​Liveness versus readiness

​Response format

​Wiring it up

Liveness versus readiness

Response format

Wiring it up