# SDK Core

This Core version of the Cometh Connect SDK 4337 provides the essential functions for managing smart accounts. It supports various authentication providers such as EOA, Magic, Web3Auth, Turnkey, and Privy, allowing developers to create and interact with smart accounts efficiently.

The Core SDK **does not require an API key**. However, some advanced features, such as the **Cometh Passkey signer**, are not available in this version.

### Install

<pre><code><strong>npm i @cometh/connect-core-sdk viem
</strong></code></pre>

### Setup

```typescript
import { 
    createComethPaymasterClient, 
    createSafeSmartAccount, 
    createSmartAccountClient,
    providerToSmartAccountSigner
} from "@cometh/connect-core-sdk";
import { arbitrumSepolia } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";
import { http } from "viem";

const bundlerUrl = process.env.NEXT_PUBLIC_4337_BUNDLER_URL;
const paymasterUrl = process.env.NEXT_PUBLIC_4337_PAYMASTER_URL;

const signer = await providerToSmartAccountSigner(
    window.ethereum
);

const publicClient = createPublicClient({
    chain: arbitrumSepolia,
    transport: http(),
    cacheTime: 60_000,
    batch: {
        multicall: { wait: 50 },
    },
});
​
const smartAccount = await createSafeSmartAccount({
    chain: arbitrumSepolia,
    publicClient,
    signer,
})

const paymasterClient = await createComethPaymasterClient({
    transport: http(paymasterUrl),
    chain: arbitrumSepolia,
    publicClient,
});

 const smartAccountClient = createSmartAccountClient({
    account: smartAccount,
    chain,
    bundlerTransport: http(bundlerUrl),
    paymaster: paymasterClient,
    userOperation: {
        estimateFeesPerGas: async () => {
            return await paymasterClient.getUserOperationGasPrice();
        },
    }
})
```

### SDK Core Features

#### Send a transaction

```typescript
import { smartAccountClient } from "./client";
import countContractAbi from "../contract/counterABI.json";

const calldata = encodeFunctionData({
    abi: countContractAbi,
    functionName: "count",
});
  
const txHash =  await smartAccountClient.sendTransaction({
    to: COUNTER_CONTRACT_ADDRESS,
    data: calldata,
});
```

#### Send batch transactions

<pre class="language-typescript"><code class="lang-typescript">const txHash =  await smartAccountClient.sendTransaction({
<strong>calls: [
</strong>      {
        to: COUNTER_CONTRACT_ADDRESS,
        data: calldata,
      },
      {
        to: COUNTER_CONTRACT_ADDRESS,
        data: calldata,
      },
    ],
});
</code></pre>

#### Sign a message

```typescript
const signature = await smartAccountClient.signMessage({message: "Hello world"});
```

#### Encode contract calls&#x20;

```typescript
const encodeCalls = await smartAccount.account.encodeCalls([
    {
        to: COUNTER_CONTRACT_ADDRESS,
        data: encodeFunctionData({
            abi: countContractAbi,
            functionName: "count",
        }),
    },
]);
```

### Specify contract addresses

By default, the SDK Core uses the following contract addresses:

```typescript
const defaultSafeContractConfig = {
    safeProxyFactoryAddress: "0x4e1DCf7AD4e460CfD30791CCC4F9c8a4f820ec67",
    safeSingletonAddress: "0x29fcB43b46531BcA003ddC8FCB67FFE91900C762",
    multisendAddress: "0x38869bf66a61cF6bDB996A6aE40D5853Fd43B526",
    setUpContractAddress: "0x2dd68b007B46fBe91B9A7c3EDa5A7a1063cB5b47",
    safe4337ModuleAddress: "0x75cf11467937ce3F2f357CE24ffc3DBF8fD5c226",
};
```

If you want to specify custom contract addresses, you can pass the `safeContractConfig` parameter when creating a smart account:

```typescript
const smartAccount = await createSafeSmartAccount({
    chain: arbitrumSepolia,
    publicClient,
    signer,
    safeContractConfig
})
```

#### Type of `safeContractConfig`:

```typescript
type SafeContractParams = {
  safeProxyFactoryAddress: Address;
  safeSingletonAddress: Address;
  multisendAddress: Address;
  setUpContractAddress: Address;
  safe4337ModuleAddress?: Address;
};
```