Overview

The Radian Paymaster allows you to pay gas fees in any token, so long as the token has sufficient liquidity on either the Radian Exchange or any of the aggregated exchanges to swap a sufficient amount of the token for ETH.

"Needing ETH" has been a long-standing issue for the Ethereum ecosystem. Furthermore, the requirement of having to make a separate transaction to "approve" a token to be spent by a smart contract has been a major source of confusion and UX friction for users. The Radian Paymaster solves both of these problems.

Subsidizing Users of Your Token

Although supplying liquidity for your token (in the case it has none) in order to allow users of your token to transact without ETH is completely practical, the paymaster also provides a method to subsidize the gas costs of users of your token more directly. You can supply liquidity to the Paymaster Pool which is a special pool where only the paymaster is allowed to trade. In the paymaster pool, you can set the exchange rate between your token and ETH such that the price is constant, which avoids any slippage and also is immune to arbitrage attacks since only the paymaster can interact with it.

Yield Generation

The paymaster also acts as a source of yield to all Radian holders, in a way that is a win-win for both Radian holders and paymaster users. After the paymaster pays for a transaction, there will be a small amount of change left over in the form of ETH. Since we assume that users of the paymaster will make efficient gas estimations (since they are incentivized to do so), the paymaster does not send back change. This is because it is entirely possible that it would cost more in gas to send the change back than the value of the change itself.

Therefore, the paymaster instead makes no transfer of the change, and it gets left in the paymaster contract. Once this change accumulates to a certain threshold (set by governance), the paymaster will automatically send the ETH to the collector. Because Radian holders can redeem RAD for the underlying assets in the collector, this acts as a source of yield for Radian holders.