Transaction - Transaction payment transaction that contains data required for money transfer.

Flow — step-by-step description of the procedure required to process the transaction.

Flow Selector — criteria that a transaction must meet to apply a particular flow.

Flow Step — a part of the transaction processing procedure that advances progress.

Extension — bank software that implements step functions.

Step Function — Stateful Function that implements the step.

Step Function Command — Command that the engine sends to the step function.

Step Function Result — Message that the step function sends to the engine as a response to the command after command execution is completed or failed