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Send EVM and Solana transactions

This guide shows you how to send transactions on both EVM networks and Solana from a single multichain session — no network switching required.

Prerequisites​

  • A multichain client initialized and connected as shown in the quickstart.
  • For building Solana transactions, install @solana/web3.js:
npm install @solana/web3.js

Initialize and connect​

Set up the multichain client and connect to both ecosystems:

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

const client = await createMultichainClient({
  dapp: {
    name: 'Multichain Demo',
    url: window.location.href,
  },
  api: {
    supportedNetworks: {
      ...getInfuraRpcUrls('YOUR_INFURA_API_KEY'),
    },
  },
})

await client.connect(
  ['eip155:1', 'eip155:137', 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp'], // Ethereum, Polygon, Solana
  []
)

Understand RPC routing​

The multichain client routes EVM methods based on type:

RouteMethodsTransport
RPC nodeeth_call, eth_getBalance, eth_blockNumber, eth_getTransactionReceipt, eth_estimateGas, eth_getCode, eth_getLogsInfura / custom RPC URL from supportedNetworks
Walleteth_sendTransaction, personal_sign, eth_signTypedData_v4, wallet_switchEthereumChain, wallet_addEthereumChainMetaMask (extension or mobile)

All Solana methods route through the MetaMask wallet — there is no RPC node fallback for Solana.

Send an EVM transaction​

Use invokeMethod to send a transaction on any EVM chain in the session:

const txHash = await client.invokeMethod({
  scope: 'eip155:1', // Ethereum Mainnet
  request: {
    method: 'eth_sendTransaction',
    params: [
      {
        from: '0xYourAddress',
        to: '0xRecipientAddress',
        value: '0x2386F26FC10000', // 0.01 ETH in hex wei
        gas: '0x5208', // 21000 gas (optional)
      },
    ],
  },
})
console.log('ETH tx hash:', txHash)

Target a different chain by changing the scope — for example, eip155:137 for Polygon:

const txHash = await client.invokeMethod({
  scope: 'eip155:137',
  request: {
    method: 'eth_sendTransaction',
    params: [
      {
        from: '0xYourAddress',
        to: '0xRecipientAddress',
        value: '0x2386F26FC10000', // 0.01 POL in hex wei
      },
    ],
  },
})
console.log('POL tx hash:', txHash)

Estimate gas​

Use eth_estimateGas to estimate the gas cost before sending. This routes to the RPC node and does not prompt the user:

const gasEstimate = await client.invokeMethod({
  scope: 'eip155:1',
  request: {
    method: 'eth_estimateGas',
    params: [
      {
        from: '0xYourAddress',
        to: '0xRecipientAddress',
        value: '0x2386F26FC10000',
      },
    ],
  },
})
console.log('Estimated gas:', gasEstimate)

Build and send a Solana transaction​

Build a transaction with @solana/web3.js, serialize it to base64, then send it with solana_signAndSendTransaction. This signs and broadcasts the transaction in one step:

import { Connection, PublicKey, SystemProgram, Transaction } from '@solana/web3.js'

const connection = new Connection('https://solana-mainnet.infura.io/v3/YOUR_INFURA_API_KEY')
const fromPubkey = new PublicKey('YourSolanaPublicKey')
const toPubkey = new PublicKey('RecipientSolanaPublicKey')

const transaction = new Transaction().add(
  SystemProgram.transfer({
    fromPubkey,
    toPubkey,
    lamports: 1_000_000, // 0.001 SOL
  })
)

transaction.recentBlockhash = (await connection.getLatestBlockhash()).blockhash
transaction.feePayer = fromPubkey

const serialized = transaction.serialize({
  requireAllSignatures: false,
  verifySignatures: false,
})
const base64Transaction = Buffer.from(serialized).toString('base64')

const result = await client.invokeMethod({
  scope: 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp',
  request: {
    method: 'solana_signAndSendTransaction',
    params: {
      transaction: base64Transaction,
    },
  },
})
console.log('SOL tx signature:', result.signature)

Sign a Solana transaction without sending​

Use solana_signTransaction to get the signed transaction back without broadcasting it. This is useful when you need to inspect or modify the signed output before submitting:

const signResult = await client.invokeMethod({
  scope: 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp',
  request: {
    method: 'solana_signTransaction',
    params: {
      transaction: base64Transaction,
    },
  },
})

// Broadcast the signed transaction yourself
const signedBuffer = Buffer.from(signResult.transaction, 'base64')
const txId = await connection.sendRawTransaction(signedBuffer)
console.log('Transaction ID:', txId)

Error handling​

Error codeDescriptionAction
4001User rejected the requestShow a retry option. Do not treat as an application error.
-32002Request already pendingWait for the user to respond in MetaMask before retrying.
try {
  const txHash = await client.invokeMethod({
    scope: 'eip155:1',
    request: {
      method: 'eth_sendTransaction',
      params: [
        {
          from: '0xYourAddress',
          to: '0xRecipientAddress',
          value: '0x2386F26FC10000',
        },
      ],
    },
  })
} catch (err) {
  if (err.code === 4001) {
    console.log('User rejected the transaction')
    return
  }
  if (err.code === -32002) {
    console.log('A transaction request is already pending')
    return
  }
  throw err
}

Next steps​

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