Spree Payments

PaymentMethod (pm_, belongs_to :store)       — a configured way to pay (STI: SpreeStripe::Gateway, Spree::PaymentMethod::Check, …)
  ├── PaymentSession (ps_)                     — gateway-side session (e.g. Stripe PaymentIntent); owned by a cart or order
  ├── PaymentSetupSession (pss_)               — save a payment method for later (e.g. SetupIntent); belongs to a customer
  └── GatewayCustomer                          — provider customer id per customer (internal, encrypted at rest)
Payment (py_)  — one attempt against a cart/order (cart_id + order_id; #owner)
  ├── source: CreditCard (card_) | PaymentSource (wallets, BNPL, bank) | StoreCredit (credit_)
  └── Refund (re_) × n  — with a RefundReason (rr_)

A payment is linked to its session by payment.response_code == payment_session.external_id. A cart can carry several payments (e.g. store credit + card).

Payment statuses (no state machine)

status is a plain string (Spree::HasStatus) written only by the payment workflows and Spree::Payment::Processing: