GRAFT network uses a unique technology called Real-Time Authorizations (RTA) which allows to process instant transaction authorizations and preauthorizations. More info about RTA and preauthorizations here (see sections 4 and 3 respectively) - https://www.graft.network/2018/11/20/how-graft-is-similar-to-and-at-the-same-time-different-from-visa-and-other-payment-card-networks-part-1/