curl --request POST \
  --url https://{workspace}.spreesuite.com/billspree/connections/make-connections \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "method": "Create",
  "action": "Create Subscription",
  "apiVersion": "v2",
  "batchUpload": false,
  "connection": {
    "serviceCode": "DEMO-001",
    "tariffCode": "DemoPlan",
    "batchCode": null,
    "addonTariffLabels": [],
    "connectionRefNo": null,
    "description": null,
    "postType": "Post Subscription",
    "paymentMethod": null,
    "projectName": null,
    "connectionInputs": [
      {
        "name": "MeterNo",
        "value": "12345"
      }
    ],
    "meteredConnectionInputs": [],
    "unmeteredInputs": [],
    "meters": [],
    "accounts": [],
    "users": [],
    "variants": [],
    "address": null
  }
}
'

{
  "success": true,
  "statusCode": 200,
  "message": "Request Succeeded.",
  "error": null,
  "data": {}
}