ethereumjs-tx Returned error: invalid sender

External question — Ethereum Stack Exchange Author: Cryptoineer Original post: https://ethereum.stackexchange.com/questions/87606 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. When i am trying to send signed transaction via ethereumjs-tx. I get this Returned error: invalid sender web3Http.eth.getTransactionCount(myAddress,"pending").then(function(blockcount){ result = web3Http.utils.toWei(amt.toString(), 'ether'); count = blockcount; var rawTransaction = { "from":myAddress, "gasPrice":web3Http.utils.toHex(20* 1e9), "gasLimit":web3Http.utils.toHex(210000), "to":contractAddress,"value":"0x0", "data":contract.methods.approve(fromAddress,web3Http.utils.toHex(result)).encodeABI(), "nonce":web3Http.utils.toHex(count) } var transaction = new Tx(rawTransaction,{'chain':'rinkeby',hardfork: 'petersburg'}); transaction.sign(Buffer.from(process.env.Key, 'hex')); web3Http.eth.sendSignedTransaction('0x'+transaction.serialize().toString('hex')) .on('receipt', ((data)=>{ resolve(data); }))

External answer — Ethereum Stack Exchange Author: nameless Original post: https://ethereum.stackexchange.com/a/131511 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Change the below const Tx = require('ethereumjs-tx').Transaction; var transaction_data = { "from": myAddress, "gasPrice": web3Http.utils.toHex(20 * 1e9), "gasLimit": web3Http.utils.toHex(210000), "to": contractAddress, "value": "0x0", "data": contract.methods.safeTransferFrom(myAddress, toAddress, tokenId).encodeABI(), } var privateKey = Buffer.from('abcde', 'hex') var transaction = new Tx(transaction_data,{ chain: 'ropsten' , hardfork: 'petersburg' }); transaction.sign(privateKey); web3Http.eth.sendSignedTransaction('0x' + transaction.serialize().toString('hex')) .on('transactionHash', console.log); to the below const Tx = require('ethereumjs-tx').Transaction; var transaction_data = { "from": myAddress, "gasPrice": web3Http.utils.toHex(20 * 1e9), "gasLimit": web3Http.utils.toHex(210000), "to": contractAddress, "value": "0x0", "data": contract.methods.safeTransferFrom(myAddress, toAddress, tokenId).encodeABI(), } var privateKey ='abcde' web3Http.eth.accounts.signTransaction(transaction_data, privateKey) .then(function(value){ web3Http.eth.sendSignedTransaction(value.transaction_data) .then(function(response){ console.log("response:" + JSON.stringify(response, null, ' ')); }) }) web3Http.eth.accounts.signTransaction will take the burden of including the correct chainId and nonce . Reference: https://github.com/ChainSafe/web3.js/issues/1040