curl -X POST https://api2.ecomailapp.cz/transactional/send-template \
  -H "key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "message": {
      "template_id": 1,
      "subject": "Email subject",
      "from_name": "Sender'\''s name",
      "from_email": "foo@bar.cz",
      "reply_to": "foo@bar.cz",
      "to": [
        {
          "email": "to@me.com",
          "name": "Recipient'\''s name"
        }
      ],
      "global_merge_vars": [
        {"name": "mergeTagName", "content": "mergeTagValue"}
      ],
      "options": {
        "click_tracking": true,
        "open_tracking": true
      }
    }
  }'

{
  "results": {
    "total_rejected_recipients": 0,
    "total_accepted_recipients": 2,
    "id": 11668787484950529
  }
}