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Installation

npm install @biconomy/abstractjs viem
1

Basic Setup

Import the required dependencies and set up your signer:
import { createMeeClient, toMultichainNexusAccount, getMEEVersion, MEEVersion } from "@biconomy/abstractjs";
import { http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { base, optimism } from "viem/chains";

const eoa = privateKeyToAccount(Bun.env.PRIVATE_KEY as `0x${string}`)
2

Creating a Multichain Nexus Account

Biconomy MEE orchestration uses the Nexus smart account system. The toMultichainNexusAccount method calculates addresses for the Nexus account on all specified chains.
const orchestrator = await toMultichainNexusAccount({
  chainConfigurations: [
    {
      chain: optimism,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0)
    },
    {
      chain: base,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0)
    }
  ],
  signer: eoa
})
Lazy DeploymentAccounts are not deployed at this point - only their addresses are calculated. Deployment happens just-in-time when the first transaction is pushed to each chain.

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Configuration Parameters

ParameterDescriptionRequired
chainsArray of chains your app will useYes
transportsViem-style transports (RPC URLs) in the same order as chainsYes
signerThe user wallet authorized to perform orchestrationYes
accountAddressOverride address for EIP-7702 orchestration (use EOA address)No

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EIP-7702 Enabled Orchestration

For EIP-7702 based orchestration (commonly used with embedded wallets like Privy, Dynamic, Magic), override the account address: 
const orchestrator7702 = await toMultichainNexusAccount({
  chainConfigurations: [
    {
      chain: optimism,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0)
    },
    {
      chain: base,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0)
    }
  ],
  signer: eoa,
  accountAddress: eoa.address
})

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Key Difference

Setting accountAddress: eoa.address tells the function to use the EOA address directly instead of calculating smart account deployment addresses. The MEE Relayer will call the execute function on the user’s EOA address, which requires the user to authorize the Nexus account via EIP-7702 delegation.

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Creating an MEE Client

Orchestration, gasless execution, and all other MEE features are provided by MEE Nodes. Create an MEE client to connect to these nodes: 
const meeClient = await createMeeClient({
  account: orchestrator,
  apiKey: 'your-api-key',
  url: 'https://mee-node-url'
})
Read the EIP-7702 Guide Here

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MEE Client Parameters

ParameterDescriptionRequired
accountThe orchestrator account instanceYes
apiKeyAPI key for authentication (rate limiting applied without it)No
urlMEE Node URL (defaults to Biconomy Network if not specified)No
When no URL is provided, the client connects to the Biconomy Network - a globally distributed network of MEE Nodes run by professional operators. View operators at https://token.biconomy.io.