Error: Returned error: nonce too low

Question

const Web3 = require('web3');
const { ethers } = require('ethers');
const { Web3Provider } = require('@ethersproject/providers');

// Virtual addresses

const fromAddress = '0x1234567890123456789012345678901234567890';
const privateKey = '0x1234567890123456789012345678901234567890123456789012345678901234';
const toAddress = '0x0987654321098765432109876543210987654321';

// Set up provider const provider = new

Web3.providers.HttpProvider('https://mainnet.infura.io/v3/f8863437e6e44eb5a850c074eb3eb8ad');
const web3 = new Web3(provider);
const { BigNumber } = require('bignumber.js');
const Tx = require('ethereumjs-tx').Transaction;

// Connect to Metamask

const ethersProvider = new Web3Provider(web3.currentProvider);

// Set up wallet

const wallet = new ethers.Wallet(privateKey, ethersProvider);

exports.transfer = async (req, res) => {
  try {
    const amount = web3.utils.toWei('1', 'ether');
    const currentNonce = await web3.eth.getTransactionCount(fromAddress, 'latest');
    const accountNonce =
      '0x' + (await web3.eth.getTransactionCount(fromAddress) + 1).toString(16)

    const txObject = {
      to: toAddress,
      value: web3.utils.toHex(amount),
      gas: web3.utils.toHex(21000),
      gasPrice: web3.utils.toHex(web3.utils.toWei('10', 'gwei')),
      nonce: accountNonce
    };

    const signedTx = await web3.eth.accounts.signTransaction(txObject, privateKey);

    const result = await web3.eth.sendSignedTransaction(signedTx.rawTransaction);

    res.send(`Transaction hash: ${result.transactionHash}`);
  } catch (error) {
    console.error(error);
    res.status(500).send('Something went wrong');
  }
}

Answer 1

The nonce is an increasing numeric value. You're trying to assign a hexadecimal value and here comes the error. Try to remove the "0x" prefix and the base 16 conversion:

const amount = web3.utils.toWei('1', 'ether');
    const currentNonce = await web3.eth.getTransactionCount(fromAddress, 'latest');
    const accountNonce =
      await web3.eth.getTransactionCount(fromAddress) + 1;

    const txObject = {
      to: toAddress,
      value: web3.utils.toHex(amount),
      gas: web3.utils.toHex(21000),
      gasPrice: web3.utils.toHex(web3.utils.toWei('10', 'gwei')),
      nonce: accountNonce
    };

Also, unless you know what you're doing, I suggest you reading this answer on how to set the nonce value correctly.