How it works
When you send a payment, you can supply a reference for yourself (payments.internalReference) and a reference for the recipient (payments.externalReference).
For payments.external.reference, we allow a maximum of 256 characters. However, it’s important to note that each payment scheme has their own reference limits and this can be as low as 18 characters. If a payment reference exceeds the limit set by the payment scheme, it will be truncated.