Get the Subscription ID

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

GET /api/v2/Smart/Transactions/STX_3MTRMHGGS2NT543DYK2VT3MUMZ6BA2 HTTP/1.1
Authorization: Bearer qb56tjj1bcvo9n2nj4u38k84lo
Accept: application/json

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

HTTP/1.1 200 OK
Content-Type: application/json
"object": "smart.transactions",
// ...
"container": {
"object": "payment.containers",
"transactions": [
"object": "payment.transactions",
    // ...
"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",
// ...

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