Get the Subscription ID

After the Smart Transaction is started, it contains the subscription ID. You can obtain it by reading the Smart Transaction:

Request
GET /api/v2/Smart/Transactions/STX_3MTRMHGGS2NT543DYK2VT3MUMZ6BA2 HTTP/1.1
Host: connect-testing.secupay-ag.de
Authorization: Bearer qb56tjj1bcvo9n2nj4u38k84lo
Accept: application/json

If everything is fine, the API responds with 200 OK, and the representation of the Smart Transaction:

Response
HTTP/1.1 200 OK
Content-Type: application/json
...
 
{
"object": "smart.transactions",
"id": "STX_3MTRMHGGS2NT543DYK2VT3MUMZ6BA2",
// ...
"container": {
"object": "payment.containers",
"id": "PCT_J0KNRWG67AV66AHKXRF2BU82N90ZES"
},
"transactions": [
{
"object": "payment.transactions",
"id": "PCI_FDBREW9ZS7P6FTN4ZY2ATC6NK0QWO7"
}
],
    // ...
"created": "2020-11-06T11:09:31+01:00",
"updated": "2020-11-06T11:12:07+01:00",
"status": "ok",
// ...
"payment_method": "debit",
"trans_id": 32424911,
// ...
  "subscription": {
"object": "payment.subscriptions",
"id": "SUB_42O0GYET3ZHAA94EW5VQ0EPGRO80Y2"
},
// ...
}

The subscription ID is found in subscription/id. The status of a started Smart Transaction for Subscription is ok.