curl --request POST \
  --url https://api.wellapp.ai/v1/subscriptions/webhooks \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "type": "webhook",
  "attributes": {
    "target_url": "https://webhook.site/d96a94d9-8458-4956-857e-11c85843baa2",
    "event": "document.processed",
    "headers": {
      "secret": "secret"
    }
  }
}
'

{
  "data": {
    "type": "webhook",
    "id": "6843888f-1aa5-440b-afac-b0edca649ad2",
    "attributes": {
      "event": "document.processed",
      "target_url": "https://webhook.site/d96a94d9-8458-4956-857e-11c85843baa2",
      "headers": {
        "secret": "secret"
      },
      "created_at": "2025-09-22T08:57:03.662Z",
      "active": true
    }
  }
}