chain-devkit

Local blockchain development bootstrap. On npm install, it:

1. Generates a secp256k1 dev account and writes it to .env.
2. Writes a chain.config.yaml network config — fetched from a remote default if reachable, otherwise falls back to a local node config (127.0.0.1:8545, chain ID 1337).

It also exposes a small set of viem-based helpers so the generated account is immediately usable against a local RPC.

⚠️ Development use only. The generated key is written in plaintext to .env on your machine and is meant for local testing against a dev/test chain (e.g. Anvil, Hardhat Network). Never fund it with real assets or use it on mainnet.

Install

npm install chain-devkit

This runs the postinstall step described above. Both .env and chain.config.yaml are generated once — if either file already exists, generation is skipped so re-running npm install won't overwrite an account you're already using.

Usage

const {
  getDevAccount,
  getConfig,
  getPublicClient,
  getWalletClient,
  getBalance,
  sendEth,
} = require("chain-devkit");

// Raw values
const { privateKey, publicKey } = getDevAccount();
const config = getConfig(); // { network, rpcUrl, chainId }

// Balance of the generated dev account
const balance = await getBalance();

// Send ETH from the dev account
const txHash = await sendEth({ to: "0xRecipient...", valueEth: "0.1" });

API

| Function | Description | | --- | --- | | getDevAccount() | Returns { privateKey, publicKey } (hex, no 0x prefix) read from .env. | | getConfig() | Returns the parsed chain.config.yaml (network, rpcUrl, chainId). | | getChain() | Returns a viem Chain object built from getConfig(). | | getDevSigner() | Returns the dev account as a viem Account (via privateKeyToAccount). | | getPublicClient() | Returns a viem PublicClient for the configured RPC. | | getWalletClient() | Returns a viem WalletClient signing with the dev account. | | getBalance(address?) | Balance of address, defaulting to the dev account. | | sendEth({ to, valueEth }) | Sends ETH from the dev account to to. |

All of these expect a chain to actually be reachable at rpcUrl (e.g. run anvil or npx hardhat node locally) — the config alone doesn't start a node for you.

Config resolution

chain.config.yaml is generated once, on first install:

1. postinstall requests https://chain-devkit.com/config (3s timeout).

2. On success, that YAML response becomes your config.

3. On any failure (timeout, network error, bad response), it falls back to:

   network: local
   rpcUrl: http://127.0.0.1:8545
   chainId: 1337

Edit chain.config.yaml directly at any time to point at a different network — it's only generated when the file doesn't already exist.

License

MIT