Travel Rule

In plainer words

The Travel Rule is a rule set by the international AML body FATF, and its core is simple: when a transfer exceeds a threshold, the sending institution must pass identity details of "who sent it and to whom" to the receiving institution — the information must "travel" with the money, hence the name. It originally governed banks and wire transfers, then extended to crypto-asset service providers (exchanges, custodians, etc.). The point is to keep identity from "breaking" mid-chain, so laundering can be traced. Why is it hard for agent payments? Agent payments are often between anonymous wallets, at machine speed, small and frequent — the "who's the sender, who's the receiver" simply doesn't exist in the traditional sense. Whoever settles on this path (the facilitator) may be required to meet this rule. It's one of the problems a compliance layer has to solve ahead of time, and an unavoidable checkpoint when regulation lands.