TransferRate setting in the XRP Ledger allows financial institutions that issue currency in the XRP Ledger to charge users a transfer fee for sending the currencies issued by that financial institution. The sender of the transfer is debited an extra percentage based on the transfer fee, while the recipient of the transfer is credited the intended amount. The difference is the transfer fee, which becomes the property of the issuing address, and is no longer tracked in the XRP Ledger. The transfer fee does not apply when sending or receiving directly to and from the issuing account, but it does apply when transferring from an operational address to another user.
XRP never has a transfer fee, because it never has an issuer.
For example, ACME Bank might set the transfer fee to 1%. For the recipient of a payment to get 2 EUR.ACME, the sender must send 2.02 EUR.ACME. After the transaction, ACME's outstanding obligations in the XRP Ledger have decreased by 0.02€, which means that ACME no longer needs to hold that amount in the account backing its issued currencies.
The following diagram shows an XRP Ledger payment of 2 EUR.ACME from Alice to Charlie with a transfer fee of 1%:
In accounting terms, Alice's, ACME's, and Charlie's balance sheets may have changed like this:
Transfer Fees in Payment Paths
A transfer fee applies whenever an individual transfer would move issued currency from one party to another through the issuing account. In more complex transactions, this can occur multiple times. Transfer fees apply starting from the end and working backwards, so that ultimately the sender of a payment must send enough to account for all fees. For example:
In this scenario, Salazar (the sender) holds EUR issued by ACME, and wants to deliver 100 USD issued by WayGate to Rosa (the recipient). FXMaker is a currency trader with the best offer in the order book, at a rate of 1 USD.WayGate for every 0.9 EUR.ACME. If there were no transfer fees, Salazar could deliver 100 USD to Rosa by sending 90 EUR. However, ACME has a transfer fee of 1% and WayGate has a transfer fee of 0.2%. This means:
- FXMaker must send 100.20 USD.WayGate for Rosa to receive 100 USD.WayGate.
- FXMaker's current ask is 90.18 EUR.ACME to send 100.20 USD.WayGate.
- For FXMaker to receive 90.18 EUR.ACME, Salazar must send 91.0818 EUR.ACME.
The transfer fee is represented by a setting on the issuing address. The transfer fee cannot be less than 0% or more than 100% and is rounded down to the nearest 0.0000001%. The transfer fee applies to all currencies issued by the same account. If you want to have different transfer fees for different currencies, use different issuing addresses for each currency.
In the XRP Ledger protocol, the transfer fee is specified in the
TransferRate field, as an integer which represents the amount you must send for the recipient to get 1 billion units of the same currency. A
1005000000 is equivalent to a transfer fee of 0.5%. By default, the
TransferRate is set to no fee. The value of
TransferRate cannot be set to less than
1000000000 ("0%" fee) or more than
2000000000 (a "100%" fee). The value
0 is special case for no fee, equivalent to
Anyone can check an account's
TransferRate with the account_info method. If the
TransferRate is omitted, then that indicates no fee.
Note: The fix1201 amendment, introduced in
rippled v0.80.0 and enabled on 2017-11-14, lowered the maximum transfer fee to 100% from an effective limit of approximately 329% (based on the maximum size of a 32-bit integer). The ledger may still contain accounts with a transfer fee setting higher than 100% (a
2000000000). Any transfer fees already set continue to apply at their stated rate.
Client Library Support
Some client libraries have convenience functions for getting and setting
xrpl.percentToTransferRate() to convert a percentage transfer fee from a string to the corresponding