ERC-721 Interaction

Reading and writing ERC-721 NFTs on Sei with viem and ethers

ERC-721 Interaction

Standard ERC-721 contracts work on Sei without modification. This page covers reading token ownership, transferring NFTs, and managing approvals.

Setup

viem

import { createPublicClient, createWalletClient, http, parseAbi } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import { sei } from '@sei-js/precompiles/viem';

const client = createPublicClient({ chain: sei, transport: http() });
const account = privateKeyToAccount('0xYourPrivateKey');
const walletClient = createWalletClient({ account, chain: sei, transport: http() });

const ERC721_ABI = parseAbi([
  'function name() view returns (string)',
  'function symbol() view returns (string)',
  'function totalSupply() view returns (uint256)',
  'function balanceOf(address owner) view returns (uint256)',
  'function ownerOf(uint256 tokenId) view returns (address)',
  'function tokenURI(uint256 tokenId) view returns (string)',
  'function getApproved(uint256 tokenId) view returns (address)',
  'function isApprovedForAll(address owner, address operator) view returns (bool)',
  'function approve(address to, uint256 tokenId)',
  'function setApprovalForAll(address operator, bool approved)',
  'function transferFrom(address from, address to, uint256 tokenId)',
  'function safeTransferFrom(address from, address to, uint256 tokenId)',
  'event Transfer(address indexed from, address indexed to, uint256 indexed tokenId)',
  'event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId)',
]);

const NFT = '0xNFTContractAddress';

Reading Token Data

viem

const tokenId = 1n;

const [owner, uri, approved] = await Promise.all([
  client.readContract({ address: NFT, abi: ERC721_ABI, functionName: 'ownerOf', args: [tokenId] }),
  client.readContract({ address: NFT, abi: ERC721_ABI, functionName: 'tokenURI', args: [tokenId] }),
  client.readContract({ address: NFT, abi: ERC721_ABI, functionName: 'getApproved', args: [tokenId] }),
]);

Checking Ownership Count

viem

const balance = await client.readContract({
  address: NFT,
  abi: ERC721_ABI,
  functionName: 'balanceOf',
  args: ['0xOwnerAddress'],
});

Transferring an NFT

viem

const hash = await walletClient.writeContract({
  address: NFT,
  abi: ERC721_ABI,
  functionName: 'safeTransferFrom',
  args: [account.address, '0xRecipient', 1n],
});

const receipt = await client.waitForTransactionReceipt({ hash });

Approving a Single Token

viem

const hash = await walletClient.writeContract({
  address: NFT,
  abi: ERC721_ABI,
  functionName: 'approve',
  args: ['0xOperatorAddress', 1n],
});

Approving All Tokens (Operator)

viem

// Grant operator approval
const hash = await walletClient.writeContract({
  address: NFT,
  abi: ERC721_ABI,
  functionName: 'setApprovalForAll',
  args: ['0xOperatorAddress', true],
});

// Revoke
const revokeHash = await walletClient.writeContract({
  address: NFT,
  abi: ERC721_ABI,
  functionName: 'setApprovalForAll',
  args: ['0xOperatorAddress', false],
});

Watching Transfer Events

viem

const unwatch = client.watchContractEvent({
  address: NFT,
  abi: ERC721_ABI,
  eventName: 'Transfer',
  onLogs: (logs) => {
    logs.forEach(({ args }) => {
      console.log(`Token ${args.tokenId}: ${args.from} → ${args.to}`);
    });
  },
});

// Stop watching
unwatch();

CosmWasm NFT Compatibility

CW721 tokens on Sei have ERC-721 pointer contracts that expose the standard ERC-721 interface. You can use all of the patterns above against a CW721 pointer address. See Pointer Contracts for how to look up the pointer address.