curl -X PATCH https://api.mailofly.com/templates/tmpl_123 \
  -H "Authorization: Bearer mf_live_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "Welcome aboard {{name}}!"
  }'

{
  "data": {
    "id": "tmpl_123",
    "name": "Welcome Email",
    "subject": "Welcome aboard {{name}}!",
    "updatedAt": "2026-09-11T13:40:00Z"
  }
}