Multichain.js

multichain.js is a TypeScript library that allows you to control accounts on multiple chains from a single NEAR Account

Installation

yarn add multichain.js

Usage

import { Account } from '@near-js/accounts'
import { KeyPair } from '@near-js/crypto'
import { JsonRpcProvider } from '@near-js/providers'
import { KeyPairSigner } from '@near-js/signers'
import { getAdapter, chains } from 'multichain.js'

async function main() {
  // NEAR Account
  const provider = new JsonRpcProvider({ url: 'https://test.rpc.fastnear.com' })

  const nearAccountId = 'your-account.near'
  const signer = new KeyPairSigner(KeyPair.fromString('ed25519:...'))
  const account = new Account(nearAccountId, provider, signer)

  // Ethereum Adapter
  const adapter = getAdapter({ chain: chains.ARBITRUM })
  const { address } = await adapter.getControlledAccount({ nearAccountId })

  const balance = await adapter.getBalance({ address })

  const txHash = await adapter.transfer({
    to: '0x2f318C334780961FB129D2a6c30D0763d9a5C970',
    amount: '10000000000000000', // 0.01 ETH
    nearAccount: account,
  })

  console.log('Address:', address)
  console.log('Balance:', balance)
  console.log('Transaction:', tx)
}

main()

If you want to use a testnet NEAR account be sure to add the mpcNetwork: testnet parameter to getAdapter

  const adapter = getAdapter({ chain: chains.ARBITRUM, mpcNetwork: 'testnet' })

You can control multiple accounts on each chain, for that you only need to change the addressIndex (defaults to 0) on both getControlledAccount and transfer

  const { address } = await adapter.getControlledAccount({ nearAccountId, addressIndex: 1 })

  const txHash = await adapter.transfer({
    to: '0x2f318C334780961FB129D2a6c30D0763d9a5C970',
    amount: '10000000000000000', // 0.01 ETH
    nearAccount: account,
    addressIndex: 1
  })

Supported Chains

The library provides chain adapters for the following blockchain networks:

• EVM Chains: Ethereum, BSC, Polygon, Arbitrum, Optimism, and other EVM-compatible networks

Each chain adapter provides a unified interface for:

• Check balance of native and fungible tokens
• Transfer native and fungible tokens