Hardhat plugin

@bkc-network-lib/hardhat makes hardhat run, hardhat test, Hardhat Ignition and hardhat verify work against BKC without changing your scripts.

Install

The plugin targets Hardhat 2. On that line, several Nomic packages have released majors that require Hardhat 3 and npm picks those by default, so pin the versions:

npm i -D hardhat@^2.26.0 "@nomicfoundation/hardhat-ethers@^3.0.8" ethers@^6
npm i -D @bkc-network-lib/hardhat
npm i -D @nomicfoundation/hardhat-verify                          # for hardhat verify
npm i -D "@nomicfoundation/hardhat-ignition-ethers@^0.15.0"       # only if you use Ignition

Configure

// hardhat.config.js
require("@nomicfoundation/hardhat-ethers");
require("@bkc-network-lib/hardhat");
require("dotenv").config();

module.exports = {
  solidity: { version: "0.8.24", settings: { optimizer: { enabled: true, runs: 200 } } },
  sourcify: { enabled: false },                 // BKC is not on Sourcify
  networks: {
    bkc: {
      url: process.env.BKC_EVM_RPC,             // https://rpc.bkc.network — reads
      chainId: 262144,
      bkc: {
        cosmosRpcUrl: process.env.BKC_COSMOS_RPC, // https://comet-rpc.bkc.network — writes
        seed: process.env.BKC_SEED,               // 32-byte hex ML-DSA-65 seed
        gasPrice: "5000000bkc",
        explorerUrl: process.env.BKC_EXPLORER,    // https://explorer.bkc.network
      },
    },
  },
};

Field	Required	Meaning
url	yes	EVM JSON-RPC
chainId	recommended	262144
bkc.cosmosRpcUrl	yes	CometBFT RPC, where writes are broadcast
bkc.seed	one of	32-byte ML-DSA-65 seed, hex, 0x optional
bkc.mnemonic	one of	BIP-39 phrase, derived with BKC's HKDF scheme
bkc.hdPath	no	default m/44'/118'/0'/0/0
bkc.bech32Prefix	no	default bkc
bkc.gasPrice	no, but set it	5000000bkc. Unset, the SDK default applies (66,666,666,667 per gas, ~13,000× the minimum) — bkc-doctor flags it
bkc.baseGasLimit	no	Cosmos gas for the signature envelope, before the EVM budget
bkc.explorerUrl	no	Blockscout URL — enough for hardhat verify
bkc.explorerApiUrl	no	when the API is not at <explorerUrl>/api

Nothing about the chain is compiled into the package: endpoints, chain id, gas price and explorer all come from your config, so a testnet reset or a moved node is an .env edit, not a plugin release. The published package reads no environment variables itself.

TypeScript configs (hardhat.config.ts) work and the bkc block is typed; Hardhat 2 loads them through ts-node, which needs TypeScript 5.

Tasks

npx hardhat bkc-new-account              # a development account: seed + addresses
npx hardhat bkc-doctor --network bkc     # checks endpoints, account, balance, gas price
npx hardhat bkc-account --network bkc    # the account in use, balance and nonce

Run bkc-doctor first on a new machine; every failing line says what to fix.

What the plugin does

• eth_sendTransaction is wrapped in MsgExecuteEvmCall, signed and broadcast; the EVM hash comes back so tx.wait() resolves against a real receipt.
• Accounts come from the chain. The network is forced to accounts: "remote" and eth_accounts returns the ML-DSA account, so ethers.getSigners() works. A private key in networks.<name>.accounts is ignored with a warning.
• Writes are serialised. call_nonce must equal the Cosmos sequence exactly, so concurrent writes would reject each other; Promise.all([...]) in a script is queued instead.
• Reads are untouched — eth_call, eth_getLogs, receipts and gas estimation go straight to the EVM endpoint.
• hre.network.bkc.address() returns { bech32, evm }.

const factory = await hre.ethers.getContractFactory("Storage");
const storage = await factory.deploy();
await storage.waitForDeployment();
await (await storage.set(42)).wait();

Hardhat Ignition

Works, with two adjustments:

module.exports = {
  // …
  ignition: { requiredConfirmations: 1 },   // blocks are under a second
};

npx hardhat ignition deploy ignition/modules/Storage.js --network bkc

Ignition refuses to start while earlier transactions from the same account are still settling (IGN403); let a block or two pass after a script that sent some.

Limits

• No local signing: eth_sign, personal_sign, eth_signTypedData_v4 fail with an explanation.
• eth_sendRawTransaction is not supported, and never will be.
• One account per network.

See What does not work for Foundry, Remix and other tools.