I have the following function and don't want to manually sign the transaction every time it's called, how would I go about setting up a way of signing this transaction with an object. I've seen sendRawTransaction and account.signTransaction but can't figure out a way to implement these in my issue.

this.contractObject = this.contractObject = {from: this.account, gas:300000};

this.contract.methods.createCountry(arg1, 1rg2, arg3).send(this.contractObject, (err, res) => {
                if (err) {
                    throw err;
                } else {

The following function gets added in a batch, I don't know if this will matter.

1 Answer 1


First, you need to generate your transaction, here is an example:

   let tx_builder = contractInstance.methods.myMethod(arg1, arg2, ...);
let encoded_tx = tx_builder.encodeABI();
let transactionObject = {
    gas: amountOfGas,
    data: encoded_tx,
    from: from_address,
    to: contract_address

Then you can sign the transaction, using the address and the private key of this specific address. When it is signed, you can send it to the node:

        web3g.eth.accounts.signTransaction(transactionObject, private_key, function (error, signedTx) {
        if (error) {
        // handle error
    } else {
        .on('receipt', function (receipt) {
            //do something

Edit: After signing it, you don't have to send it. You can add it to the batch request.

  • This is exactly what I was looking for! I'll test the solution and get back at you with the result.
    – jasper
    Commented May 17, 2018 at 14:55
  • I still get an error on the web3.eth.sendSignedTransaction() function, the thing is that the error is really vague so I have no idea what is going on.. Do you have any idea? errors.js:29 Uncaught (in promise) Error: Returned error: {"id":14,"jsonrpc":"2.0","error":{"code":-32603}}
    – jasper
    Commented May 18, 2018 at 7:25
  • Is your node having an RPC endpoint opoenned? Commented May 18, 2018 at 10:29
  • I have ganache open and all other functions that make use of Ganache do work.
    – jasper
    Commented May 18, 2018 at 10:35
  • I created a new question for this issue: ethereum.stackexchange.com/questions/48807/…
    – jasper
    Commented May 18, 2018 at 10:36

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