🔗psp:// URIThe wire-level contract. A requester PISP generates a URI; any conforming payer PISP can resolve and act on it.
↔️Inter-PISP ProtocolPISP ↔ PISP coordination — URI resolution, payment progression, and Stage 1/2 dispute handling.
🏛️Scheme Authority ProtocolPISP ↔ SA coordination — governance, fee plans, settlement reporting, and Stage 3 escalation.
🔌Settlement AdaptersA plugin interface for bank connectivity. The reference implementation ships OBIE, TrueLayer, and internal adapters.
📋Reference ProfilesNon-normative patterns for the requester and payer-app boundaries. Use them as a starting point, not a constraint.
🔐Security by designmTLS on inter-PISP transport, JWS message signing, CRL revocation, and a documented threat model.