core/app.json

{
  "healthchecks": {
    "web": [
      {
        "type": "startup",
        "name": "web check",
        "description": "Checking if the app responds to the GET /",
        "path": "/",
        "attempts": 3,
        "warn": true,
        "initialDelay": 1
      }
    ]
  }
}