The secret key can be gotten from the 'Settings' page on your Startbutton dashboard.
Query key
Required?
Description
transactionReference
Yes
This can be either:
1. the refund transaction reference. This reference provides the details and status of the refund processed.
2. the original transaction reference. This reference provides a list of all refunds associated with the transaction (in cases of multiple partial refunds).
The refund transaction reference can be obtained from the email you receive after a Refund is processed or from the Refunds tab on the Dashboard, while the original transaction reference can be obtained from the Dashboard or webhook notification.