Card management API
stripe.com
stripe.com
First ACH, and now this. Nice work, again, Stripe.
You're right that you can't use a separate card for subscriptions yet -- we just use the customer's default card. We'd love to hear your feedback on this though (feel free to ping me at amber@stripe.com)!
Currently that has to be abstracted away on client-side databases and we end up having multiple 'Stripe customers' associated with a single client, so it fudges our customer count in the Stripe management interface.
What would the ideal behavior be if your customer updates their default card? Should the recurring billing continue chugging along with the card it was created with, or use the new card instead?
The concept of a "default" card would come up when creating a new subscription or charge, and would be presented as the default selected payment option. The user would be able to select another card or add a new one.
I'm thinking of something similar to Amazon's checkout credit card selection screen.
Most major websites that have check-outs operate similarly to how you describe, but there's no 'default' card presented at check-out -- instead it displays the last card used for the last purchase.