How Domestic Fast-Payment Systems Meet Across a Border

Cross-border payments become operational only when separate domestic systems have a working path between them. The specific question is what an interlink adds to two fast payment systems that would otherwise remain local, and how that arrangement changes when one corridor becomes many. The Singapore–Thailand example gives readers a documented way to connect system design with user-visible results, while the wider evidence shows why one successful link should not be mistaken for a global solution.

An interlink is not simply a faster version of an existing domestic rail. It is an arrangement that lets payment systems or their participants exchange or pass on transactions across jurisdictions. The arrangement may be bilateral, connect through a single access point, use a common platform or coexist with correspondent-banking relationships. It has to define more than a technical route: the participating institutions, the supported payment uses, the responsibilities at each handoff and the conditions under which the receiving side can complete the transaction.

What the Singapore–Thailand corridor changed

The Singapore–Thailand FPS interlink, launched in 2021, is often cited because it makes the idea of a working corridor concrete. Its initial focus was person-to-person payments, including remittances. Instead of requiring a sender to navigate a long and opaque chain, the reported user path allowed them to enter a recipient’s phone number in a PSP’s mobile application. The domestic fast-payment systems remained distinct, but the link gave them a way to cooperate for a defined cross-border use case.

The results reported by the BIS brief are visible at the user level. Transfers that had taken two or three days through traditional methods could be completed in seconds. Transaction costs in the corridor fell from as much as 10% of the payment value to less than 3%. The applications displayed fees and charges before the sender confirmed the transfer, improving predictability as well as speed. Transfer volume through the link grew by 16% in 2024 and reached more than 870,000 transfers.

Those results demonstrate several things at once. First, a domestic FPS can provide the fast local processing needed for a retail payment, but it cannot deliver the cross-border outcome without an arrangement on the other side. Second, the link can improve transparency by making charges visible before confirmation rather than leaving the sender to discover the total cost later. Third, the value of the arrangement is measured in a defined corridor, not in the abstract existence of two modern payment systems.

The user experience can make the architecture look effortless. A phone number and a seconds-scale confirmation conceal the institutional work required behind the interface. A sending PSP must know how to submit the transaction into its domestic system. The interlink must recognise the relevant participant and pass the payment toward the other jurisdiction. A receiving PSP must be able to identify the payee and complete its side of the process. The arrangement must also operate under the rules agreed by the linked systems.