curl -X POST https://senderr.dev/api/v1/send \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your-api-key" \
  -d '{
    "template_id": "550e8400-e29b-41d4-a716-446655440000",
    "to": ["[email protected]"],
    "subject": "Welcome!",
    "variables": {
      "name": "John Doe"
    }
  }'

{
  "success": true,
  "data": {
    "id": "re_01H123ABC...",
    "from": "[email protected]",
    "to": [
      "[email protected]"
    ],
    "subject": "Welcome to our platform!",
    "sent_at": "2024-01-01T12:00:00Z"
  },
  "meta": {
    "email_usage": {
      "monthly_limit": 1000,
      "current_usage": 45,
      "remaining": 955,
      "plan_type": "monthly",
      "is_overage": false,
      "overage_emails": 0,
      "stripe_usage_reported": false
    }
  }
}