Is this possible to pay for ERC721 token with ERC20 token not ETH?

Question

I can create NFT's with an ERC20 token but I want to set the price of a NFT to an ERC20 token too, not ETH.

For example on OpenSea I can sell my NFT's for ETH but I want to get payed in any ERC20 token I would like to.How could I do that?

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You can reach the contract I developed here and you can get help by contacting me.

Current Solution

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Diagram of the contract structure

Answer 1

Yes, this is a common question.

I have fully spelled this out as a demo project including the smart contracts and the front end JavaScript.

https://github.com/fulldecent/spend-ERC20-create-ERC721

This project was sponsored by Arianee.

Answer 2

Where to start - read about ERC20 tokens and the approval mechanism.

Your front end will issue 2 transactions for the user to sign - one to approve the ERC20 payment, and one to your "mint" function which will transfer the payment to you and send the tokens to the user.

If you don't know how to do this, read about ERC20's allowance mechanism.

Answer 3

I come late to the party but I want to answer as I was working on a similar problem for several days and the answer is quite simple.

I am showing here an example to use USDC inside a ERC721 contract. The first step is to use an interface in your ERC721 contract so you can access the functions in the ERC20 contract:

interface USDC{
    function balanceOf(address owner) external view returns (uint);    
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
}

Then in your constructor you have to add the address of the ERC20 token contract (in my case I used the goerli USDC contract):

constructor() ERC721("Mavon Minted NFTs", "MNFTs") {
        owner = msg.sender;
        USDc = USDC(0x98339D8C260052B7ad81c28c16C0b98420f2B46a);
 }

And finally, in the function where the transaction is made, you add the following ERC20 function:

 USDc.transferFrom(msg.sender, seller, priceUSD);   

Now, a very important thing and that took me a couple of days to discover, is that to use transferFrom, the buyer has to give your contract approval to move the funds in his wallet. This is accomplished by using the ERC20 function approve(spender, amount). The thing is, this approve function cannot be called within the same contract where you have the function that makes the funds transaction, so you have two options:

• make another contract to approve the transaction so you can use transferFrom;
• call the approve function in the ERC20 contract from the frontend, like you would do with any other contract.