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Access a user's accounts

User accounts are used in a variety of contexts in Ethereum, including as identifiers and for signing transactions. To request a signature from a user or have a user approve a transaction, your dapp must access the user's accounts using the eth_requestAccounts RPC method.

When accessing a user's accounts:

  • Only initiate a connection request in response to direct user action, such as selecting a connect button.
  • Always disable the connect button while the connection request is pending.
  • Never initiate a connection request on page load.
tip

You can also use MetaMask SDK to enable a reliable, secure, and seamless connection from your dapp to a MetaMask wallet client.

Create a connect button​

We recommend providing a button to allow users to connect MetaMask to your dapp. Selecting this button should call eth_requestAccounts to access the user's account.

In the example project code, the following JavaScript code accesses the user's accounts when they select a connect button, and the following HTML code displays the button and the current account:

index.js
// You should only attempt to request the user's account in response to user
// interaction, such as selecting a button.
// Otherwise, you popup-spam the user like it's 1999.
// If you fail to retrieve the user's account, you should encourage the user
// to initiate the attempt.
const ethereumButton = document.querySelector('.enableEthereumButton');
const showAccount = document.querySelector('.showAccount');

ethereumButton.addEventListener('click', () => {
  getAccount();
});

// While awaiting the call to eth_requestAccounts, you should disable
// any buttons the user can select to initiate the request.
// MetaMask rejects any additional requests while the first is still
// pending.
async function getAccount() {
  const accounts = await window.ethereum.request({ method: 'eth_requestAccounts' })
    .catch((err) => {
      if (err.code === 4001) {
        // EIP-1193 userRejectedRequest error
        // If this happens, the user rejected the connection request.
        console.log('Please connect to MetaMask.');
      } else {
        console.error(err);
      }
    });
  const account = accounts[0];
  showAccount.innerHTML = account;
}

Handle accounts​

Use the eth_accounts RPC method to handle user accounts. Subscribe to the accountsChanged provider event to be notified when the user changes accounts.

In the example project script, the following code handles user accounts and detects when the user changes accounts:

index.js
let currentAccount = null;
window.ethereum.request({ method: 'eth_accounts' })
  .then(handleAccountsChanged)
  .catch((err) => {
    // Some unexpected error.
    // For backwards compatibility reasons, if no accounts are available,
    // eth_accounts returns an empty array.
    console.error(err);
  });

// Note that this event is emitted on page load.
// If the array of accounts is non-empty, you're already
// connected.
window.ethereum.on('accountsChanged', handleAccountsChanged);

// eth_accounts always returns an array.
function handleAccountsChanged(accounts) {
  if (accounts.length === 0) {
    // MetaMask is locked or the user has not connected any accounts.
    console.log('Please connect to MetaMask.');
  } else if (accounts[0] !== currentAccount) {
    // Reload your interface with accounts[0].
    currentAccount = accounts[0];
    // Update the account displayed (see the HTML for the connect button)
    showAccount.innerHTML = currentAccount;
  }
}
note

In the future, the accounts array may contain more than one account. This functionality isn't available yet. The first account in the array will always be considered the user's "selected" account.