Master Hardhat Console: Debug Smart Contracts Instantly

Overview

Hardhat console provides an interactive REPL connected to a local Hardhat network, allowing developers to query state and interact with contracts without writing separate scripts.

Prerequisites

Start a local node and launch the console:

npx hardhat node

npx hardhat console --network localhost

Querying Chain State

Accounts

// Get signer objects
const signers = await ethers.getSigners();
console.log("First account:", signers[0].address);

Note: getSigners() returns Signer objects that can sign transactions.

Balance

const balanceWei = await ethers.provider.getBalance(signers[0].address);
console.log("Balance (Wei):", balanceWei.toString());
console.log("Balance (Ether):", ethers.formatEther(balanceWei));

Block number

const blockNumber = await ethers.provider.getBlockNumber();
console.log("Current block:", blockNumber);

Interacting with a Deployed Contract

Assume a contract Greeter has been deployed with scripts/deploy.js and its address is known.

// scripts/deploy.js
async function main() {
  const Greeter = await ethers.getContractFactory("Greeter");
  const greeter = await Greeter.deploy("Hello, Hardhat!");
  await greeter.deployed();
  console.log("Greeter deployed to:", greeter.address);
}
main();

Attach to the contract

const Greeter = await ethers.getContractFactory("Greeter");
const greeter = await Greeter.attach("0x5FbDB2315678afecb367f032d93F642f64180aa3");
console.log("Connected to Greeter at:", greeter.address);

Read‑only call

const current = await greeter.greet();
console.log("Current greeting:", current);

State‑changing call

const tx = await greeter.setGreeting("Hola, Hardhat Console!");
await tx.wait(); // wait for mining
console.log("Greeting updated, tx hash:", tx.hash);

After the transaction is mined, read the new value:

const updated = await greeter.greet();
console.log("Updated greeting:", updated);

Advanced Console Capabilities

Send ETH directly from the REPL using signer.sendTransaction.

Query past events with contract.queryFilter.

Control block production with Hardhat’s RPC methods such as evm_mine or evm_increaseTime.

Illustrations