curl --request POST \
  --url https://api.naturalead.ai/api/leads/sync \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "leads": [
    {
      "lead_id": "<string>",
      "phone": "<string>",
      "name": "<string>",
      "email": "[email protected]",
      "custom_fields": {}
    }
  ]
}
'

{
  "total": 123,
  "created": 123,
  "updated": 123,
  "failed": 123,
  "errors": [
    {
      "lead_id": "<string>",
      "error": "<string>"
    }
  ]
}