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Payments

GHO is an ERC-20 contract which also implements EIP-2612 to support signature based approvals. This guide will walk-through the different methods for transferring GHO tokens as well as provide ideas, resources, and inspiration for hackathon projects.

transfer​

The simplest method for transferring ERC-20 tokens is transfer which can be used to send tokens to any address without a prior token approval. The limitation of transfer is that it must be executed directly by the token holder, so it cannot be used within a smart contract function call.

transferFrom​

To transfer tokens within a smart contract function, transferFrom is the method that is used. The transferFrom function requires the sender to have approved the spender address for at least the transfer amount. There are two methods which can be used to perform the approval:

approve​

The standard ERC-20 approve requires an on-chain transaction from the token holder to a approve a specified spender and amount.

permit​

EIP-2612 permit is a type of token approval which requires two components:

  • A signed approval message from the token holder which encodes: owner, spender, amount, nonce, deadline, DOMAIN_SEPERATOR
  • An on-chain permit transaction which can be executed from any address

The advantages to using permit in place of approve are that the gas cost of the transaction can be paid for by an address other than the token owner, and can reduce the number of transactions by batching the permit call with another action, an example of this is supplyWithPermit from Aave Protocol V3.

Ideas​

  • SDK or widget to allow application to embed GHO as payment input and convert to their desired recipient chain/token
  • Integration with Aave facilitator to borrow GHO on-demand for payments
  • Application to improve user experience of managing GHO borrows and transfers
  • Integration with Web2 <-> Web3 payment gateway
  • Smart contract wallet integration

Resources​

Inspiration​