Etherscan
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Getting Started
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Tutorials
Signing Raw Transactions
The closest real world example of a raw transaction — probably a bank cheque
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Some ways we can utilize raw transactions include signing a transaction offline on a secure machine and then broadcasting it separately or to send a transaction at a later point of time.
1. Setting up a Node.js project
In a new folder, initiate a new Node.js project with the command
npm init -y to accept all default project parameters.A
package.json file will be created for you, which contains all your packages and project information.
2. Integrating Ethers.js
We'll need to integrate a helpful JavaScript library known as Ethers.js that will help with interacting with the Ethereum blockchain.
We can do so using the command
npm i ethers from a terminal within this project, which will add ethers as a dependency. 
We'll then create a new file named
transaction.js where we'll write the rest of the code in JavaScript and import ethers at the top of the file. 1
const ethers = require('ethers');
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async function main() {
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// rest of code goes here
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}
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main();
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3. Creating a wallet
One of the useful classes that Ethers.js provides is a
Wallet, which represents a regular Ethereum address that you can use to store and send Ether. 1
const ethers = require('ethers');
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async function main() {
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// defining the wallet private key
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let privatekey = 'CE75F1A875F2DB7FB064F5DBD302B0C77FFEAA18CC4C314167A5111A04F79AFA';
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let wallet = new ethers.Wallet(privatekey);
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// print the wallet address
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console.log('Using wallet address ' + wallet.address);
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}
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main();
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4. Crafting the transaction
A transactions is made up of several parameters that have to be defined, for this example we'll be making a simple ETH transfer.
If you are following this article on a testnet, feel free to get some testnet Ether
to fund your address.
Parameter
Description
to
the
address to send Ether tovalue
the amount of Ether to send
gasLimit
maxPriorityFeePerGas
maxFeePerGas
nonce
type
set to
0x2, to denote EIP-1559 type transactionschainId
The sample code to send
1 Ether to address 0xEeee7341f206302f2216e39D715B96D8C6901A1C on the Ropsteh testnet will be as follows. 1
const ethers = require('ethers');
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async function main() {
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let privatekey = 'CE75F1A875F2DB7FB064F5DBD302B0C77FFEAA18CC4C314167A5111A04F79AFA';
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let wallet = new ethers.Wallet(privatekey);
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console.log('Using wallet address ' + wallet.address);
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let transaction = {
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to: '0xa238b6008Bc2FBd9E386A5d4784511980cE504Cd',
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value: ethers.utils.parseEther('1'),
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gasLimit: '21000',
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maxPriorityFeePerGas: ethers.utils.parseUnits('5', 'gwei'),
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maxFeePerGas: ethers.utils.parseUnits('20', 'gwei'),
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nonce: 1,
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type: 2,
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chainId: 3
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};
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}
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main();
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5. Sign & serialize
After detailing the contents of the transaction, we'll need to sign it — using the wallet's private key we created in Step 3 to prove we are allowed to spend funds in the wallet address.
With the transaction signed, we have just one more step to serialize, or simply converting our transaction into a hexadecimal format.
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const ethers = require('ethers');
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async function main() {
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let privatekey = 'CE75F1A875F2DB7FB064F5DBD302B0C77FFEAA18CC4C314167A5111A04F79AFA';
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let wallet = new ethers.Wallet(privatekey);
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console.log('Using wallet address ' + wallet.address);
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let transaction = {
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to: '0xa238b6008Bc2FBd9E386A5d4784511980cE504Cd',
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value: ethers.utils.parseEther('1'),
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gasLimit: '21000',
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maxPriorityFeePerGas: ethers.utils.parseUnits('5', 'gwei'),
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maxFeePerGas: ethers.utils.parseUnits('20', 'gwei'),
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nonce: 1,
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type: 2,
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chainId: 3
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};
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// sign and serialize the transaction
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let rawTransaction = await wallet.signTransaction(transaction).then(ethers.utils.serializeTransaction(transaction));
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// print the raw transaction hash
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console.log('Raw txhash string ' + rawTransaction);
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}
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main();
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6. Send via API
With the signed raw transaction, we can now pass it to the "eth_sendRawTransaction" endpoint to be broadcasted to the Ethereum network.
A successfully broadcasted transaction will return a transaction hash, which you can use the "eth_getTransactionbyHash" endpoint or look it up on Etherscan!
You can run this code using the command
node transaction.js1
const ethers = require('ethers');
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const fetch = require('node-fetch');
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async function main() {
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let privatekey = 'CE75F1A875F2DB7FB064F5DBD302B0C77FFEAA18CC4C314167A5111A04F79AFA';
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let wallet = new ethers.Wallet(privatekey);
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console.log('Using wallet address ' + wallet.address);
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let transaction = {
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to: '0xa238b6008Bc2FBd9E386A5d4784511980cE504Cd',
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value: ethers.utils.parseEther('1'),
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gasLimit: '21000',
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maxPriorityFeePerGas: ethers.utils.parseUnits('5', 'gwei'),
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maxFeePerGas: ethers.utils.parseUnits('20', 'gwei'),
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nonce: 1,
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type: 2,
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chainId: 3
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};
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let rawTransaction = await wallet.signTransaction(transaction).then(ethers.utils.serializeTransaction(transaction));
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console.log('Raw txhash string ' + rawTransaction);
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// pass the raw transaction hash to the "eth_sendRawTransaction" endpoint
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let gethProxy = await fetch(`https://api-ropsten.etherscan.io/api?module=proxy&action=eth_sendRawTransaction&hex=${rawTransaction}&apikey=YourApiKeyToken`);
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let response = await gethProxy.json();
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// print the API response
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console.log(response);
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}
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main();
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Wrapping Up
The full sample code for this tutorial is on Github, feel free to fork and extend the functionality of it !
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Last modified 6mo ago