[Unit help center]: closing an account does not cancel in-flight activity. Pending debit-card authorizations in Authorized status go through; new authorizations are declined automatically. Outgoing ACHs initiated before closure still go through. Incoming ACHs after closure are returned with AccountClosed (R02); you get webhook events for them and can see them in the dashboard, as you can for declined post-closure card authorizations. Plan webhook handling for the AccountClosed return code before closing accounts programmatically.

Context: Closing an account with pending payments and authorizations. Pending ACHs and authorized card transactions still settle; new ones decline.