Using the Nexus APIs

Nexus provides a collection of APIs that allow PSPs to communicate and send payments across borders.

Connecting to a Nexus Gateway

The Nexus Gateway is a software component which enables Nexus payments. Each IPS in the Nexus network must operate a Gateway. Each Gateway connects to the domestic IPS infrastructure on one side and to Nexus Gateways in other countries on the other side.

Each participant will be issued API credentials by the IPSO, allowing them to connect to Nexus.

For PSPs

There are two models for a PSP to communicate with the Nexus Gateway, depending on the local IPS implementation:

• Via the IPS: All communication will go through the existing secure connection between the PSP and the IPS. The IPS will provide pass-through APIs that forward requests to the local Nexus Gateway APIs (and vice versa).

• Via a common shared network: Where a secure network exists between all PSPs and the IPSO, the IPSO may request PSPs communicate directly with the Nexus Gateway. In this case, the local Nexus Gateway would have its own identifier or address on the secured network.

Nexus Gateways will also support communication through message queues where this is used by the IPS and PSPs.

For FXPs

An FXP can connect to any Nexus Gateway. The FXP should choose the one most convenient for them and then consistently communicate with that chosen Gateway. Their choice could be based on jurisdiction, geographical location or any other consideration.

The Gateway will ensure that any data generated in response to the FXP’s API calls will be distributed to the appropriate Gateways in the Nexus network.

For SAPs

As SAPs are PSPs, they will connect to Nexus through the same mechanism as PSPs. As mentioned above, this may vary depending on the SAP.

For Proxy Lookup Service Operators

The IPSOs can communicate with the local Nexus Gateway through APIs or message queuing.

For Proxy Lookup Service Operators

Each IPSO will be responsible for arranging communication between the local Nexus Gateway and the proxy lookup service.

The PLSO must provide an API or a message queue endpoint at which it can receive proxy lookup requests from the Nexus Gateway. (These requests could be sent directly from the Nexus Gateway, or passed through via the local IPS, depending on the local network configuration.)

The PLSO must send proxy lookup responses to the Nexus Gateway API or endpoint as provided by the IPSO.

The PLSO must ensure necessary message security through eg API credentials, API secrets, hashing and message signing.