Send a batch of emails

curl -X POST 'https://www.unitpost.com/api/v1/email/batch' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'User-Agent: my-app/1.0' \
  -H 'Content-Type: application/json' \
  -d '{
    "emails": [
      {
        "from": "you@yourdomain.com",
        "to": "a@example.com",
        "subject": "Hi A",
        "html": "<p>Hi A</p>"
      },
      {
        "from": "you@yourdomain.com",
        "to": "b@example.com",
        "subject": "Hi B",
        "html": "<p>Hi B</p>"
      }
    ]
  }'

{
  "object": "list",
  "batch_id": "batch_123",
  "status": "queued",
  "scheduled_at": "2026-01-01T00:00:00.000Z",
  "data": [
    {
      "id": "id_123"
    }
  ],
  "failed": [
    {
      "index": 0,
      "error": "string"
    }
  ]
}