I'm aware of the customer.subscriptions.trial_will_end event. It fires 3 days before a trial ends.
I couldn't find an event that actually fires when the trial is over and the customer hasn't paid. This would be useful to do something simple like this to turn off features:
customer.update_attributes(active_account: false)
Without a webhook like that, I'm looking at scheduling some tasks to check unconfirmed customers periodically and turn off features accordingly. The webhook seems cleaner though and less prone to errors on my side. Is there an event/webhook in line with these goals? FYI, customers don't have to put in a card when they start the trial - so autobilling is not an option.
When the trial period ends, there will be a customer.subscription.updated event and an invoice.created event. An hour (or so) later, you'll then either see an invoice.payment_succeeded event or an invoice.payment_failed event. From those, you'll know whether the payment went through or not.
Cheers, Larry
PS I work on Support at Stripe.