Metamask: Metamask API support for interacting with Ethereum contracts

Metamask: A Guide to Interacting with Ethereum Contracts via API

In 2021, MetaMask, the popular cryptocurrency wallet, made headlines by announcing that it would be abandoning its own web3 integration and relying solely on external APIs for interacting with Ethereum smart contracts. The decision was met with surprise from the crypto community, as Metamask’s API had previously been a powerful tool for developers to manage their wallets and interact with various Ethereum projects.

However, this change has left many users who rely on Metamask for managing their ERC20 and ERC721 assets without a viable alternative. In this article, we’ll explore how to use the official MetaMask API to accomplish simple tasks such as reading token balance for a wallet on an ERC721 contract.

Understanding the MetaMask API

The MetaMask API provides a set of endpoints that allow developers to interact with Ethereum smart contracts and manage their wallets. While the API has been updated since 2021, it still relies on external APIs like Web3.js or the Solidity compiler to parse and execute Ethereum bytecode.

To use the MetaMask API, you need to have a valid MetaMask account and a wallet address associated with it. Once you’re logged in, you can navigate to the “Wallet” section and click on the three vertical dots next to your wallet address. From there, select “MetaMask Account Info” > “Network” > “API” to enable API access.

Reading Token Balance for an ERC721 Contract

To read token balance for a wallet on an ERC721 contract using Metamask’s API, you can follow these steps:

• Get the account address

  : Click on your wallet address in the MetaMask Account Info section and copy it.

• Use the eth_getBalance endpoint: The eth_getBalance endpoint allows you to retrieve the current balance of a specific Ethereum account. You’ll need to replace with the actual account address associated with your MetaMask wallet.

• Send a request to the eth_blockNumber endpoint: To determine the balance, you also need the latest block number. This can be obtained by sending a GET request to

• Combine the two requests

  

  : Combine theeth_getBalanceandeth_blockNumberrequests in one API call using theconcatfunction from Web3.js.

“javascript

const web3 = require(‘web3’);

const infuraUrl = ‘

// Set up a new Web3 instance with Infura’s API key

const web3Instance = new web3.eth.Instance(infuraUrl);

// Get the account address from your MetaMask wallet

const accountAddress = ‘‘

// Use the eth_getBalance endpoint to retrieve the balance of the account

async function getBalance() {

try {

const balanceResponse = await web3Instance.getBalance(accountAddress);

return balanceResponse.balance;

} catch (error) {

console.error(‘Error getting balance:’, error);

return null;

}

}

// Use the eth_blockNumber endpoint to determine the latest block number

async function getLatestBlock() {

try {

const latestBlock = await web3Instance.eth.blockNumber();

return latestBlock;

} catch (error) {

console.error(‘Error getting latest block:’, error);

return null;

}

}

// Combine the two requests and parse the response to extract token balances

async function getBalanceAndBlocks() {

try {

const balanceResponse = await web3Instance.getBalance(accountAddress);

const latestBlockResponse = await web3Instance.eth.