BRC-721: NFTs

The BRC-721 token standard on Bitcoin is similar to ERC-721 on Ethereum. It can represent virtually anything in Bitcoin:
  • collectible items
  • memberships
  • lottery tickets
  • in-game items
  • and more

Write a BRC-721 smart contract

Extending the OpenZeppelin ERC-721 contract, we can create a hypothetical PFP NFT collection (CryptoWizards) on Bitcoin.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
contract CryptoWizards is ERC721URIStorage {
constructor() ERC721("CryptoWizards", "WIZ") {}
function safeMint(address to, uint256 tokenId, string memory uri) public {
_safeMint(to, tokenId);
_setTokenURI(tokenId, uri);
}
}

Compile the contracts

To compile your contracts, use the built-in hardhat compile task.
cd smart-contract-examples
npm install
npx hardhat compile

Deploy the contracts

Review config file hardhat.config.ts. The network configs should look like this.
networks: {
mynw: {
url: "http://localhost:10002",
accounts: {
mnemonic: "<your mnemonic with funds>"
},
timeout: 100_000,
},
blockscoutVerify: {
blockscoutURL: "http://localhost:4000", // your explorer URL
...
}
}
Run the deploy scripts using hardhat-deploy.
npx hardhat deploy --tags NFT
Make sure the accounts in hardhat.config.ts have some TC.

Interact with the contracts

Once the contracts are deployed, you can interact with them. We've prepared a few hardhat tasks to make it easy for you to interact with the contracts.
# ./CryptoWizards/wizard100.jpg
npx hardhat mint-nft --metadata wizard100.json --tokenid 100
# output should contain the URI
npx hardhat get-nft --uri bfs://22213/0xfe94d57c6ef567d26e3524f54dc2772329092ffd/0xd3b0932Dff95a56c6024328162a3040F5e717F76/100