# Sign-In with Solana (SIWS) - MetaMask Connect

> Implement Sign-In with Solana (SIWS) authentication in your dapp using MetaMask Connect, with domain binding and phishing protection.

# Sign in with Solana

[Sign-In with Solana (SIWS)](https://docs.siws.xyz/) lets users sign in to your dapp by authenticating with their MetaMask wallet, instead of a traditional username and password.

    

## Domain binding

MetaMask supports domain binding with SIWS to help prevent phishing attacks.
When a site asks a user to sign a SIWS message, but the domain in the message doesn't match the site
the user is on, MetaMask displays a warning in the sign-in interface.
The user must explicitly select to proceed, accepting the risk of a phishing attack.

:::caution important
MetaMask displays a prominent warning for mismatched domains, but does **not** block users from
bypassing the warning and accepting the sign-in request.
This avoids breaking existing dapps that may have use cases for mismatched domains.
:::

    
        
    
    
        
    

## Example

The following example shows how to set up SIWS with MetaMask using
[`solana:signMessage`](../../reference/methods.md#supported-wallet-standard-features):

```javascript title="index.js"

const solanaClient = await createSolanaClient({
  dapp: {
    name: 'My Solana Dapp',
    url: window.location.origin,
  },
})

const wallet = solanaClient.getWallet()
const { accounts } = await wallet.features['standard:connect'].connect()

const siwsSign = async siwsMessage => {
  try {
    const message = new TextEncoder().encode(siwsMessage)
    const [{ signature }] = await wallet.features['solana:signMessage'].signMessage({
      account: accounts[0],
      message,
    })
    siwsResult.innerHTML = signature
  } catch (err) {
    console.error(err)
    siwsResult.innerHTML = `Error: ${err.message}`
  }
}

siws.onclick = async () => {
  const domain = window.location.host
  const from = accounts[0].address
  const siwsMessage = `${domain} wants you to sign in with your Solana account:\n${from}\n\nI accept the MetaMask Terms of Service: https://community.metamask.io/tos\n\nURI: https://${domain}\nVersion: 1\nChain ID: 5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp\nNonce: 32891757\nIssued At: 2021-09-30T16:25:24.000Z`
  siwsSign(siwsMessage)
}
```

The following HTML displays the SIWS button:

```html title="index.html"
Sign-In with Solana
<button type="button" id="siws">Sign-In with Solana</button>
Result:
```

See the [JavaScript quickstart](../../quickstart/javascript.md) for a complete working example.

## Next steps

- [Sign messages](sign-message.md) for general-purpose offchain signatures without domain binding.
- [Send a legacy transaction](../send-transactions/legacy.md) to transfer SOL or interact with Solana programs.
- See [MetaMask Connect Solana methods](../../reference/methods.md) for the full list of Wallet Standard features.