Transactional

  curl --request POST \
  --url https://webhook.cocoonmail.com/webhook/transactional/ \
  --header 'X-COCOONMAIL-API-KEY: <API Key>' \
  --header 'Content-Type: application/json' \
  -- data '{
    "transactional_id": "<string>",
    "to": [
        {
            "email": "<string>",
            "first_name": "<string>",
            "middle_name":  "<string>",
            "last_name":  "<string>",
            "attributes" : {
                "attr1" :"<string>",
                "attr2" :"<string>"
            }
        }
    ],
    "additional_parameters":  {
        "parameter1": "<string>",
        "parameter2":  "<string>"
    }
    "sender" :"<string>",
    "attachments" :[
        {
            "filename":"<string>",
            "contentType":"<string>",
            "data" : "<string>"
        }
    ],
    "add_email_address_to_contact" : boolean
  }