curl --request POST \
  --url https://api.simpu.co/email/send \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "recipients": "john@acme.com,mack@acme.com",
  "sender_id": "jane@acme.com",
  "content": "Hello, this is just a test.",
  "from_name": "John from Acme",
  "subject": "This is a test!!!",
  "reply_to": "no-reply@acme.com",
  "external_ref": "674535b2b39158b9aae90188fcec23eb",
  "callback": "https://example.com/email/delivery_report",
  "template_id": "674535b2b39158b9aae90188fcec23eb",
  "personalisation": [
    {
      "to": "mack@acme.com",
      "substitutions": {
        "name": "Mack from Acme"
      }
    }
  ]
}'

{
  "id": "674535b2b39158b9aae90188fcec23eb",
  "recipients": [
    "mack@acme.com"
  ],
  "sender_id": "john@acme.com",
  "external_ref": "674535b2b39158b9aae90188fcec23eb",
  "callback": "https://example.com/email/delivery_report",
  "template_id": "674535b2b39158b9aae90188fcec23eb",
  "from_name": "John from Acme",
  "personalisation": [
    {
      "to": "mack@acme.com",
      "substitutions": {
        "name": "Mack from Acme"
      }
    }
  ],
  "created_datetime": "2024-06-28T23:56:38.128604+00:00",
  "updated_datetime": "2024-06-28T23:56:38.128604+00:00",
  "meta": {
    "method": "POST",
    "resource": "/email/send",
    "estimate": {
      "available_balance": 1000.5,
      "charge": 0.33
    }
  }
}