USDC Support

In addition to the standard requirements, keep in mind:

1. The mint function should be nonpayable.
2. The USDC token has 6 decimals instead of 18 like ETH, Matic, and most other tokens.
3. The totalPrice attribute in the mintConfig of your button should be in units of USDC. If your intended price is 100 USD, then you will set totalPrice to 100 e.g. totalPrice="100".
4. Your ERC-20 transfer call must request the funds from msg.sender instead of the address parameter. This allows Crossmint to pay from our fleet of treasury wallets and deliver the NFTs directly to the user’s wallet. See an example mint function below.

function mintUSDC(address _to) public {
  // pre payment logic here

  // note that you need to transfer from msg.sender, NOT the _to address
  tokenInstance.transferFrom(msg.sender, address(this), priceUSDC );

  // actual minting logic here
}