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

# Connect Custom Contracts

> Learn how to connect your custom contracts via IMA

<Note>
  The following requires `EXTRA_CONTRACT_REGISTRAR_ROLE` on the account calling **registerExtraContract**.
</Note>

## Adding Extra Contract Registrar Role on SKALE Chain

<Tabs>
  <Tab title="via SAFE">
    1. Encode the function call via [multisigwallet-cli](/developers/run-a-skale-chain/using-multisig-wallet-cli)

    ```shell theme={null}
    npx msig encodeData [SKALE Chain-name] MessageProxyForSchain grantRole 0x6155b5aac15ce9aa193c0527a6f43be0a36a7e2e7496c2b615c0e5f922842773 [0x_ACCOUNT_TO_GRANT_EXTRA_CONTRACT_REGISTRAR_ROLE_TO]
    ```

    2. Execute via SAFE by following the steps [here](/developers/run-a-skale-chain/using-safe#submit-transaction-to-safe)
  </Tab>

  <Tab title="Ethers v6">
    ```ts theme={null}
    /**
    * Run:
    * npm install ethers dotenv
    */

    import { Contract, JsonRpcProvider, Wallet } from "ethers";
    import dotenv from "dotenv";
    dotenv.config();

    const MSG_PROXY_SCHAIN_ADDR = "0xd2AAa00100000000000000000000000000000000";
    const MSG_PROXY_SCHAIN_ABI = [
    	"function grantRole(bytes32 role, address account) external"
    ];

    const provider = new JsonRpcProvider(process.env.RPC_URL);
    const wallet = new Wallet(process.env.PRIVATE_KEY, provider);
    const contract = new Contract(MSG_PROXY_SCHAIN_ADDR, MSG_PROXY_SCHAIN_ABI, wallet);
    const res = await contract.grantRole(id("EXTRA_CONTRACT_REGISTRAR_ROLE", "0x..."));
    ```

    <Note>
      This is required since the SKALE Chain does default to giving Marionette EXTRA\_CONTRACT\_REGISTRAR\_ROLE
    </Note>
  </Tab>
</Tabs>

## Registering Contracts on a SKALE Chain

* **via SAFE** -- would be if you give Marionette EXTRA\_CONTRACT\_REGISTRAR\_ROLE on MessageProxyForSchain
* **via Ethers v6** -- would be if you gave an EOA the role and use Ethers

<Tabs>
  <Tab title="via SAFE">
    1. Encode the function call via [multisigwallet-cli](/developers/run-a-skale-chain/using-multisig-wallet-cli)

    ```shell theme={null}
    	npx msig encodeData juicy-low-small-testnet MessageProxyForSchain registerExtraContract destination-skale-chain-name local-contract-address
    ```

    2. Execute via SAFE by following the steps [here](/developers/run-a-skale-chain/using-safe#submit-transaction-to-safe)
  </Tab>

  <Tab title="Ethers v6">
    ```ts theme={null}
    /**
    * Run:
    * npm install ethers dotenv
    */

    import { Contract, JsonRpcProvider, Wallet } from "ethers";
    import dotenv from "dotenv";
    dotenv.config();

    const MSG_PROXY_SCHAIN_ADDR = "0xd2AAa00100000000000000000000000000000000";
    const MSG_PROXY_SCHAIN_ABI = [
    	"function registerExtraContract(string memory chainName, address extraContract)"		
    ];

    const provider = new JsonRpcProvider(process.env.RPC_URL);
    const wallet = new Wallet(process.env.PRIVATE_KEY, provider);
    const contract = new Contract(MSG_PROXY_SCHAIN_ADDR, MSG_PROXY_SCHAIN_ABI, wallet);
    const res = await contract.registerExtraContract("elated-tan-skat", "0x...")); // elated-tan-skat is Europa Mainnet
    ```
  </Tab>
</Tabs>

## Registering Contracts on Ethereum

1. Go to [SAFE App](https://safe.global) or your preferred frontend for SAFE.
2. Press **New Transaction** and then **Transaction Builder**

<img src="https://mintlify.s3.us-west-1.amazonaws.com/skalenetwork/assets/developers/safe-transaction-builder.png" alt="Click on Transaction Builder" />

3. Input the MessageProxy address for your correct environment into the **Contract Address** field and select **Use Implementation ABI**

<Tip>
  Each SKALE Manager deployment -- Mainnet, Testnet, etc. -- has a smart contract called MessageProxy which is what sends data between Ethereum and SKALE Chains. Grab the correct address from the table below and verify by visiting the SKALE Network [Releases Repo](https://github.com/skalenetwork/concepts/tree/master/releases).
</Tip>

**MessageProxy Contract Addresses**

| Network                  | Contract Address                           |
| ------------------------ | ------------------------------------------ |
| Ethereum Mainnet         | 0x8629703a9903515818C2FeB45a6f6fA5df8Da404 |
| Ethereum Holesky Testnet | 0x682ef859e1cE314ceD13A6FA32cE77AaeCE98e28 |

4. Select `registerExtraContract` from the dropdown list in *Contract Method Selector*, set the *schainName (string)* field (e.g elated-tan-skat), and set the *extraContract (address)* field which is the smart contract on Ethereum

<img src="https://mintlify.s3.us-west-1.amazonaws.com/skalenetwork/assets/developers/custom-contract-ethereum-registration.png" alt="Input transaction details" />

5. Click **Add transaction**, scroll down, and click **Create Batch**, then click **Send Batch**. [Tenderly](https://tenderly.co/) simulation is generally available, even on testnet, and is encouraged to be used to see all the changes occuring on the Ethereum side before they occur.