I found the Sandbox Payments page where there are credit card listed for testing purposes.
But is there a way I can simulate in Sandbox a valid credit card that validates successfully but it does not have the necessary funds on it so it creates an Invoice with the status unpaid?
I want to test in Sandbox the creation of a new subscription with an invoice that has status unpaid to be able to test my applications code on how to handle the scenario.
Unfortunately there isn’t a test value that you can save to a customer profile that will simulate a decline for a subscription. We’re constantly working to improve our features based on feedback like this, so I’ll be sure to share your request to the API product team. 