Verify with Hardhat

In this guide you publish the source of a contract you deployed with Hardhat to BOTScan, using one command.

Everything on this page uses testnet (chain 968). Get free test tokens from the faucet.

What you’ll build

A verified Counter contract on BOTScan testnet, with its source on the Code tab.

Prerequisites

A Hardhat 3 project with the chainDescriptors block from Set up Hardhat. @nomicfoundation/hardhat-toolbox-viem includes the verify plugin.
A contract deployed from that project. See Deploy with Hardhat.

Steps

Check the chain descriptor

Hardhat finds BOTScan through chainDescriptors in your config. For testnet it must contain:

hardhat.config.ts

chainDescriptors: {
  968: {
    name: "BOT Chain Testnet",
    blockExplorers: {
      blockscout: {
        name: "BOTScan Testnet",
        url: "https://scan.bohr.life",
        apiUrl: "https://scan.bohr.life/api",
      },
    },
  },
},

This is a fragment. The full config is in Set up Hardhat.

Run verify

Pass the deployed address. Use the blockscout subtask so Hardhat doesn’t ask for an Etherscan key.

npx hardhat verify blockscout --network botTestnet 0xYOUR_CONTRACT

You’ll see:

Output

📤 Submitted source code for verification on BOTScan Testnet:

  contracts/Counter.sol:Counter
  Address: 0x24E48d0fcf9B5500EE3DD77f96d095Db090a9F58

⏳ Waiting for verification result...

✅ Contract verified successfully on BOTScan Testnet!

  contracts/Counter.sol:Counter
  Explorer: https://scan.bohr.life/address/0x24E48d0fcf9B5500EE3DD77f96d095Db090a9F58#code

Pass constructor arguments, if any

If your contract has a constructor with arguments, list them after the address in the same order:

npx hardhat verify blockscout --network botTestnet 0xYOUR_GREETER "Hello"

For complex arguments, see the Hardhat docs on verifying contracts.

Verify it worked

Open the Explorer link from the output. The Code tab shows a verified badge, your source and the compiler settings. The Read contract tab lets you call count.

Troubleshooting

Hardhat asks for an Etherscan API key

You ran npx hardhat verify without blockscout, so Hardhat tried Etherscan too. Add the blockscout subtask.

No block explorer configured for chain 968

The chainDescriptors entry is missing or uses a different chain ID. Add the block from step 1.

The bytecode doesn't match

The local build differs from what you deployed. Don’t change the source or compiler settings between deploying and verifying. If you did, redeploy and verify again.

has already been verified on BOTScan Testnet

The contract is verified, either by an earlier run or because BOTScan matched your bytecode to a contract verified before. Nothing else to do. Hardhat suggests --force only for partially verified contracts.

Development environment

Deploy and verify

Frontend

DeFi

Bridge

Gasless transactions

AI agents

Data and indexing

Verify with Hardhat

What you’ll build

Prerequisites

Steps

Verify it worked

Troubleshooting

Next steps

Verify in the BOTScan UI

Explorer API

​What you’ll build

​Prerequisites

​Steps

​Verify it worked

​Troubleshooting

​Next steps

Verify in the BOTScan UI

Explorer API

What you’ll build

Prerequisites

Steps

Verify it worked

Troubleshooting

Next steps