# Concepts (/concepts)

These pages explain what happens underneath a Fianto payment: the statuses a payment and a
subscription move through, when Fianto treats a payment as final, how the service fee works, and
the Solana program behind subscriptions.

- [Payment lifecycle](/concepts/payment-lifecycle): How a checkout session, its order and each payment move between statuses, and which events each move sends.

- [Subscription lifecycle](/concepts/subscription-lifecycle): How a subscription starts, renews, falls past due and ends.

- [Finality](/concepts/finality): Why the payer sees success at confirmed, but an order is paid only at finalized.

- [Fees](/concepts/fees): How Fianto's service fee is set, computed, paid and shown.

- [The Subscriptions program](/concepts/subscriptions-program): The Solana program behind Fianto subscriptions, and what it checks on every charge.