QuickNode Core Workflow A Skill

QuickNode Core Workflow A

Overview

Build EVM transaction workflows: send ETH, interact with contracts, listen for events, and handle gas estimation.

Prerequisites

Completed quicknode-hello-world
A funded wallet (use testnet for development)

Instructions

Step 1: Send ETH Transaction

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider(process.env.QUICKNODE_ENDPOINT);
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY!, provider);

const tx = await wallet.sendTransaction({
  to: '0xRecipientAddress',
  value: ethers.parseEther('0.01'),
});
console.log(`TX sent: ${tx.hash}`);
const receipt = await tx.wait();
console.log(`Confirmed in block ${receipt!.blockNumber}, gas used: ${receipt!.gasUsed}`);

Step 2: Call Contract Write Function

const contractAddress = '0xYourContract';
const abi = ['function transfer(address to, uint256 amount) returns (bool)'];
const contract = new ethers.Contract(contractAddress, abi, wallet);

const tx = await contract.transfer('0xRecipient', ethers.parseUnits('100', 18));
const receipt = await tx.wait();
console.log(`Transfer confirmed: ${receipt!.hash}`);

Step 3: Listen for Events (WebSocket)

const wsProvider = new ethers.WebSocketProvider(process.env.QUICKNODE_WSS);
const contract = new ethers.Contract(contractAddress, ['event Transfer(address indexed from, address indexed to, uint256 value)'], wsProvider);

contract.on('Transfer', (from, to, value, event) => {
  console.log(`Transfer: ${from} -> ${to}: ${ethers.formatUnits(value, 18)}`);
});

Step 4: Gas Estimation

const gasEstimate = await contract.transfer.estimateGas('0xRecipient', ethers.parseUnits('100', 18));
const feeData = await provider.getFeeData();
const totalCost = gasEstimate * (feeData.gasPrice || 0n);
console.log(`Estimated gas: ${gasEstimate}, cost: ${ethers.formatEther(totalCost)} ETH`);

Output

ETH transfer with receipt confirmation
Smart contract interaction
Real-time event listening via WebSocket
Gas estimation before transactions

Error Handling

| Error | Cause | Solution | |-------|-------|----------| | insufficient funds | Wallet balance too low | Fund wallet or reduce amount | | nonce too low | Nonce conflict | Get latest nonce: provider.getTransactionCount(address) | | gas required exceeds allowance | Contract revert | Check contract requirements |

Resources

Next Steps

NFT and token APIs: quicknode-core-workflow-b

Agent Skills: QuickNode Core Workflow A

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