Audit how my app represents subscription state and align it with how the payment provider actually models it. Check the subscription record, the access-control logic, and every webhook that mutates state. Implement a real state model: trialing (full access, card may or may not be on file, ends at trial end), active (paying, full access), past_due (payment failed, retries in progress, access policy decided deliberately: grace period or immediate downgrade), canceled (no renewal, access until paid-through date or immediately, decided deliberately), and incomplete (checkout started but payment never confirmed). Store the provider's subscription ID and the paid-through date, and derive access from state plus dates, not from a single boolean. Handle the transitions from provider webhooks only (payment succeeded, payment failed, canceled, trial ending), never from client requests. Decide and document what 'cancel' means: end of paid period is the standard users expect. Don't let users' access depend on fields the client can influence. Don't hard-delete subscription records on cancel; they're billing history. Deliver: the state model with transition map, the access rule per state, the webhook wiring per transition, and a test pass through the lifecycle: start trial, convert to paid, fail a payment, recover, cancel, and confirm access matches the documented rule at each step.