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Connect to EVM and Solana in MetaMask

This guide walks you through setting up MetaMask Connect in a multichain JavaScript dapp. By the end, your dapp can connect to EVM networks and Solana at the same time, and make requests to each one without switching between them.

Prerequisites​

  • Node.js version 19 or later installed.
  • A package manager installed, such as npm, Yarn, pnpm, or bun.
  • MetaMask installed in your browser or on mobile.

Steps​

1. Install MetaMask Connect​

Install the multichain client in an existing JavaScript project:

npm install @metamask/connect-multichain

2. Initialize the client​

Initialize the multichain client with configuration options:

import { createMultichainClient } from '@metamask/connect-multichain'

const client = createMultichainClient({
  dapp: {
    name: 'My Multichain Dapp',
    url: window.location.href,
    iconUrl: 'https://mydapp.com/icon.png',
  },
  api: {
    supportedNetworks: {
      'eip155:1': 'https://mainnet.infura.io/v3/YOUR_INFURA_API_KEY',
      'eip155:137': 'https://polygon-mainnet.infura.io/v3/YOUR_INFURA_API_KEY',
      'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp': 'https://api.mainnet-beta.solana.com',
      'solana:4sGjMW1sUnHzSxGspuhpqLDx6wiyjNtZ': 'https://api.devnet.solana.com',
    },
  },
})

This example configures MetaMask Connect with:

  • dapp — Ensures trust by showing your dapp's name, url, and iconUrl during connection.
  • api.supportedNetworks — A map of CAIP-2 chain IDs to RPC URLs for all networks supported by the dapp.

3. Connect with scopes​

Connect to MetaMask and request access to multiple chains across ecosystems:

// Connect with scopes across ecosystems - one approval for all chains
await client.connect(
  [
    'eip155:1', // Ethereum Mainnet
    'eip155:137', // Polygon
    'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp', // Solana Mainnet
  ],
  [] // Account preferences (optional)
)

The user sees a single approval prompt for all requested chains. This is a key advantage of the multichain approach — no separate connection flows per ecosystem.

4. Get session and accounts​

After connecting, retrieve the session to see which chains and accounts the user authorized:

const session = await client.getSession()

// Accounts are in CAIP-10 format (e.g. "eip155:1:0x..." or "solana:5eykt...:83ast...")
const ethAccounts = session.sessionScopes['eip155:1']?.accounts || []
const polAccounts = session.sessionScopes['eip155:137']?.accounts || []
const solAccounts = session.sessionScopes['solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp']?.accounts || []

console.log('ETH accounts:', ethAccounts)
console.log('POL accounts:', polAccounts)
console.log('SOL accounts:', solAccounts)

5. Invoke methods on any scope​

Use invokeMethod to call RPC methods on any chain in the session. Extract the address from the CAIP-10 account string to use in your requests:

// Get ETH balance on Ethereum Mainnet
if (ethAccounts.length > 0) {
  const ethAddress = ethAccounts[0].split(':')[2]
  const ethBalance = await client.invokeMethod({
    scope: 'eip155:1',
    request: {
      method: 'eth_getBalance',
      params: [ethAddress, 'latest'],
    },
  })
  console.log('ETH balance:', ethBalance)
}

// Get POL balance on Polygon
if (polAccounts.length > 0) {
  const polAddress = polAccounts[0].split(':')[2]
  const polBalance = await client.invokeMethod({
    scope: 'eip155:137',
    request: {
      method: 'eth_getBalance',
      params: [polAddress, 'latest'],
    },
  })
  console.log('POL balance:', polBalance)
}

6. Get SOL balance using Solana RPC​

note

invokeMethod doesn't currently support getBalance. If this is something you'd like to see, raise a feature request on the MetaMask Builder Hub.

To read Solana account balances, use @solana/kit to query the RPC directly:

npm install @solana/kit
import { address, createSolanaRpc } from '@solana/kit'

if (solAccounts.length > 0) {
  const solAddress = solAccounts[0].split(':')[2]
  const rpc = createSolanaRpc('https://api.mainnet-beta.solana.com')
  const balance = await rpc.getBalance(address(solAddress)).send()
  console.log('SOL balance:', balance)
}

Understanding scopes​

Scopes are CAIP-2 chain identifiers that specify which blockchain you're targeting.

EcosystemFormatExample
EVMeip155:<chainId>eip155:1 (Ethereum), eip155:42161 (Linea), eip155:137 (Polygon)
Solanasolana:<genesisHash>solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp (Mainnet), solana:4sGjMW1sUnHzSxGspuhpqLDx6wiyjNtZ (Devnet)

Full example​

import { createMultichainClient } from '@metamask/connect-multichain'
import { address, createSolanaRpc } from '@solana/kit'

async function main() {
  // 1. Initialize client
  const client = createMultichainClient({
    dapp: {
      name: 'Multichain Demo',
      url: window.location.href,
    },
    api: {
      supportedNetworks: {
        'eip155:1': 'https://mainnet.infura.io/v3/YOUR_API_KEY',
        'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp': 'https://api.mainnet-beta.solana.com',
      },
    },
  })

  // 2. Connect to both Ethereum Mainnet and Solana Mainnet
  await client.connect(['eip155:1', 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp'], [])

  // 3. Get accounts from session
  const session = await client.getSession()
  const ethAccounts = session.sessionScopes['eip155:1']?.accounts || []
  const solAccounts =
    session.sessionScopes['solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp']?.accounts || []

  console.log('ETH accounts:', ethAccounts)
  console.log('SOL accounts:', solAccounts)

  // 4. Get ETH balance
  if (ethAccounts.length > 0) {
    const ethAddress = ethAccounts[0].split(':')[2]
    const ethBalance = await client.invokeMethod({
      scope: 'eip155:1',
      request: {
        method: 'eth_getBalance',
        params: [ethAddress, 'latest'],
      },
    })
    console.log('ETH balance:', ethBalance)
  }

  // 5. Get SOL balance using @solana/kit (getBalance is not supported via invokeMethod)
  if (solAccounts.length > 0) {
    const solAddress = solAccounts[0].split(':')[2]
    const rpc = createSolanaRpc('https://api.mainnet-beta.solana.com')
    const balance = await rpc.getBalance(address(solAddress)).send()
    console.log('SOL balance:', balance)
  }

  // 6. Send an ETH transaction
  if (ethAccounts.length > 0) {
    const ethAddress = ethAccounts[0].split(':')[2]
    const txHash = await client.invokeMethod({
      scope: 'eip155:1',
      request: {
        method: 'eth_sendTransaction',
        params: [
          {
            from: ethAddress,
            to: '0x4B0897b0513FdBeEc7C469D9aF4fA6C0752aBea7',
            value: '0x29a2241af62c0000', // 3 ETH in wei
          },
        ],
      },
    })
    console.log('ETH tx hash:', txHash)
  }

  //  TODO: Send a SOL transaction
}

main()

Next steps​

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