Metamask: Metamask API support for interacting with Ethereum contracts

Metamask: A Guide to Interacting with Ethereum Contracts via API

In 2021, MetaMask, a popular cryptocurrency wallet, made headlines by announcing that it would be abandoning its own web3 integration and relying solely on external APIs to interact with Ethereum smart contracts. The decision came as a surprise to 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 left many users who rely on Metamask to manage their ERC20 and ERC721 assets without a viable alternative. In this article, we’ll look at how to use the official MetaMask API to perform simple tasks like reading the balance of a wallet token on an ERC721 contract.

Understanding the MetaMask API

The MetaMask API provides 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 such as Web3.js or the Solidity compiler to parse and execute Ethereum bytecode.

To use the MetaMask API, you must have a valid MetaMask account and an associated wallet address. Once you are 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 Details” > “Network” > “API” to enable API access.

Getting Token Balance for an ERC721 Contract

To read the token balance for an ERC721 contract wallet using the Metamask API, follow these steps:

• Get the account address

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

• Use the eth_getBalance endpoint

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

• Make a request to the eth_blockNumber endpoint: The latest block number is also required to determine the balance. You can do this by making a GET request to

• Combine the two requests: Combine theeth_getBalance’ and eth_blockNumber' requests into a single API call using theconcat’ function in Web3.js.

• Parse the response: The resulting JSON object will contain a list of balance transactions for each address in your account. You can parse this data to extract token balances.

Here is an example code snippet that demonstrates how to perform the following steps:

“` javascript

const web3 = request(‘web3’);

const infuraUrl = ‘

// Set up a new Web3 instance with your Infura 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 get the account balance

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.

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