{
  "_comment": "Klaviyo flow > Webhook action. Destination URL: your relay's HTTPS URL. Header: X-Relay-Secret = the relay's RELAY_SECRET. Body: the JSON below ({{ email }} is Klaviyo's profile email tag).",
  "destination_url": "https://<your-relay-host>/",
  "headers": {
    "X-Relay-Secret": "<the same long random string as the relay's RELAY_SECRET>"
  },
  "body": {
    "email": "{{ email }}"
  }
}