Send transactions

Handle EVM transactions in your JavaScript dapp. With the SDK, you can:

• Send transactions.
• Track transaction status in real time.
• Estimate gas costs accurately.
• Handle transaction errors gracefully.
• Manage complex transaction patterns.

You can implement transaction handling directly in JavaScript. The following are examples of sending a basic transaction and an advanced transaction with gas estimation.

Send a basic transaction

• viem
• web3.js
• ethers.js
• Ethereum API

import { MetaMaskSDK } from '@metamask/sdk'

// Initialize SDK
const MMSDK = new MetaMaskSDK()
const provider = MMSDK.getProvider()

// Get current account
const accounts = await provider.request({
  method: 'eth_requestAccounts',
})
const from = accounts[0]

// Convert ETH amount to wei (hex)
const value = `0x${(0.0001 * 1e18).toString(16)}`

// Prepare transaction
const transaction = {
  from,
  to: '0xRECIPIENT_ADDRESS',
  value,
  // Gas fields are optional - MetaMask will estimate
}

// Send transaction
const txHash = await provider.request({
  method: 'eth_sendTransaction',
  params: [transaction],
})

const tx = await provider.request({
  method: 'eth_getTransactionReceipt',
  params: [txHash],
})

import { MetaMaskSDK } from '@metamask/sdk'
import { createPublicClient, createWalletClient, custom } from 'viem'
import { mainnet } from 'viem/chains'

// Initialize SDK
const MMSDK = new MetaMaskSDK()
const provider = MMSDK.getProvider()

const publicClient = createPublicClient({ chain: mainnet, transport: custom(provider) })
const walletClient = createWalletClient({ chain: mainnet, transport: custom(provider) })

// data for the transaction
const destination = '0xRECIPIENT_ADDRESS'
const amount = parseEther('0.0001')
const address = await walletClient.getAddresses()

// Submit transaction to the blockchain
const hash = await walletClient.sendTransaction({
  account: address[0],
  to: destination,
  value: amount,
})

const receipt = await publicClient.waitForTransactionReceipt({ hash })

import { MetaMaskSDK } from '@metamask/sdk'
import { ethers } from 'ethers'
import { BrowserProvider, parseUnits } from 'ethers'

// Initialize SDK
const MMSDK = new MetaMaskSDK()
const provider = MMSDK.getProvider()

const ethersProvider = new ethers.BrowserProvider(provider)
const signer = await ethersProvider.getSigner()

const destination = '0xRECIPIENT_ADDRESS'
const amount = parseUnits('0.0001', 'ether')

// Submit transaction to the blockchain
const tx = await signer.sendTransaction({
  to: destination,
  value: amount,
})

// Wait for the transaction to be mined
const receipt = await tx.wait()

import { MetaMaskSDK } from '@metamask/sdk'
import { Web3 } from 'web3'

// Initialize SDK
const MMSDK = new MetaMaskSDK()
const provider = MMSDK.getProvider()

const web3 = new Web3(provider)

// Get user's Ethereum public address
const fromAddress = (await web3.eth.getAccounts())[0]

const destination = '0xRECIPIENT_ADDRESS'
const amount = web3.utils.toWei('0.0001') // Convert 0.0001 ether to wei

// Submit transaction to the blockchain and wait for it to be mined
const receipt = await web3.eth.sendTransaction({
  from: fromAddress,
  to: destination,
  value: amount,
})

Send an advanced transaction with gas estimation

To add gas estimation, use the eth_estimateGas RPC method.

async function estimateGas(transaction) {
  try {
    const gasEstimate = await ethereum.request({
      method: 'eth_estimateGas',
      params: [transaction],
    })

    // Add 20% buffer for safety
    return (BigInt(gasEstimate) * 120n) / 100n
  } catch (error) {
    console.error('Gas estimation failed:', error)
    throw error
  }
}

Best practices

Follow these best practices when handling transactions.

Transaction security

• Always validate inputs before sending transactions.
• Check wallet balances to ensure sufficient funds.
• Verify addresses are valid.

Error handling

• Handle common errors like user rejection and insufficient funds.
• Provide clear error messages to users.
• Implement proper error recovery flows.
• Consider network congestion in gas estimates.

User experience

• Display clear loading states during transactions.
• Show transaction progress in real time.
• Provide detailed transaction information.

Common errors

Error code	Description	Solution
4001	User rejected transaction	Show a retry option and a clear error message.
-32603	Insufficient funds	Check the balance before sending a transaction.
-32000	Gas too low	Increase the gas limit or add a buffer to the estimation.
-32002	Request already pending	Prevent multiple concurrent transactions.

Next steps

See the following guides to add more functionality to your dapp:

• Manage user accounts
• Manage networks
• Interact with smart contracts