Invoice Statuses
Compact invoice state reference.
This page covers legacy v1 fixed invoices. For new integrations use v2 payment sessions. Session and child-attempt states are not interchangeable. Advanced fee alternatives are in buyer-fee pricing.
PENDING, PAID, UNDERPAID, OVERPAID, EXPIRED, and CANCELLED. Only PAID is a normal fulfillment state, and it must come from an authenticated source.