Webhook payloads

When you configure a webhook alert channel, Happy Uptime sends a POST request with the following payload on each alert event.

Monitor down

Fired when a monitor transitions to down from any other state.

json
{
  "event": "monitor.down",
  "timestamp": "2026-03-07T14:22:00Z",
  "monitor": {
    "id": "mon_abc123",
    "name": "API Server",
    "url": "https://api.example.com/health",
    "type": "http"
  },
  "check": {
    "status": "down",
    "status_code": 503,
    "response_time_ms": 30012,
    "error_message": "HTTP 503 Service Unavailable",
    "region": "us-east",
    "checked_at": "2026-03-07T14:22:00Z"
  }
}

Monitor recovery

Fired when a monitor transitions from down back to up. Includes a downtime object with the total duration.

json
{
  "event": "monitor.recovery",
  "timestamp": "2026-03-07T14:35:00Z",
  "monitor": {
    "id": "mon_abc123",
    "name": "API Server",
    "url": "https://api.example.com/health",
    "type": "http"
  },
  "check": {
    "status": "up",
    "status_code": 200,
    "response_time_ms": 142,
    "region": "us-east",
    "checked_at": "2026-03-07T14:35:00Z"
  },
  "downtime": {
    "duration_seconds": 780,
    "started_at": "2026-03-07T14:22:00Z"
  }
}

Delivery guarantees

Webhooks are delivered with exponential backoff retries on 5xx responses or connection failures. If your endpoint returns any 2xx status, delivery is considered successful. Non-2xx responses (other than 5xx) are treated as permanent failures and not retried.

Signing secret (optional)

If you set a headers.X-Secret on the channel config, Happy Uptime forwards that header on every request. Verify the value on your side to ensure the request came from Happy Uptime.