curl --request POST \
  --url https://api.open.cx/whatsapp/send-template \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "template_id": "<string>",
  "phone_number_id": "<string>",
  "variables": [
    "<string>"
  ],
  "contact": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  },
  "session_id": "<string>"
}
'

{
  "whatsapp_message_id": "<string>",
  "opencx_message_id": "<string>",
  "opencx_session_id": "<string>"
}