> ## Documentation Index
> Fetch the complete documentation index at: https://docs.biconomy.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Setting up AbstractJS

## Installation

```bash theme={null}
npm install @biconomy/abstractjs viem
```

<Steps>
  <Step title="Basic Setup">
    Import the required dependencies and set up your signer:

    ```typescript theme={null}
    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}`)
    ```
  </Step>

  <Step title="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.

    ```typescript theme={null}
    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
    })
    ```

    <Info>
      **Lazy Deployment**

      Accounts 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.
    </Info>

    ### Configuration Parameters

    | Parameter        | Description                                                   | Required |
    | ---------------- | ------------------------------------------------------------- | -------- |
    | `chains`         | Array of chains your app will use                             | Yes      |
    | `transports`     | Viem-style transports (RPC URLs) in the same order as chains  | Yes      |
    | `signer`         | The user wallet authorized to perform orchestration           | Yes      |
    | `accountAddress` | Override address for EIP-7702 orchestration (use EOA address) | No       |
  </Step>
</Steps>

## EIP-7702 Enabled Orchestration

For EIP-7702 based orchestration (commonly used with embedded wallets like Privy, Dynamic, Magic), override the account address:

```typescript theme={null}
const orchestrator7702 = await toMultichainNexusAccount({
  chainConfigurations: [
    {
      chain: optimism,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0),
      accountAddress: eoa.address
    },
    {
      chain: base,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0),
      accountAddress: eoa.address
    }
  ],
  signer: eoa
})
```

### 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.

## 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:

```typescript theme={null}
const meeClient = await createMeeClient({
  account: orchestrator,
  apiKey: 'your-api-key',
  url: 'https://mee-node-url'
})
```

[Read the EIP-7702 Guide Here](/new/getting-started/enable-mee-eoa-7702)

### MEE Client Parameters

| Parameter | Description                                                   | Required |
| --------- | ------------------------------------------------------------- | -------- |
| `account` | The orchestrator account instance                             | Yes      |
| `apiKey`  | API key for authentication (rate limiting applied without it) | No       |
| `url`     | MEE Node URL (defaults to Biconomy Network if not specified)  | No       |

<Note>
  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](https://token.biconomy.io).
</Note>