Understanding MultichainContract

The MultichainContract is a powerful abstraction in the MEE SDK that lets you interact with the same contract across multiple chains using a single, unified interface. Think of it as a "master remote control" that can operate the same contract regardless of which chain it's deployed on.

Creating a MultichainContract

Here's how you create one:

const mcUSDC = getMultichainContract({
    abi: erc20Abi,
    deployments: [
        ["0x0b2c639c533813f4aa9d7837caf62653d097ff85", optimism.id],
        ["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913", base.id],
    ],
});

This creates a contract instance that knows about USDC on both Optimism and Base chains.

Reading From Multiple Chains

One of the most powerful features is the ability to read from multiple chains in a single call:

// Read USDC balances across multiple chains
const balances = await mcUSDC.read({
    account: mcNexus,
    functionName: "balanceOf",
    args: [accountAddress],
    onChains: [optimism, base],
});
 
// balances will be an array of:
// [
//   { chainId: optimism.id, result: 1000000n },
//   { chainId: base.id, result: 2000000n }
// ]

Instead of making separate RPC calls and handling responses for each chain, you get all the data in one clean operation.

Encoding Chain-Specific Actions

When you need to create transactions, the .on(chainId) method lets you specify which chain you're targeting:

// Create a transfer operation on Optimism
const transferOp = mcUSDC.on(optimism.id).transfer({
    args: [recipientAddress, parseUnits("100", 6)],
    gasLimit: 100000n
});
 
// Create an approval operation on Base
const approvalOp = mcUSDC.on(base.id).approve({
    args: [spenderAddress, parseUnits("1000", 6)],
    gasLimit: 100000n
});

Each operation is automatically encoded with the correct contract address for that specific chain. The SDK handles all the details of proper encoding and chain-specific parameters.

Type Safety

The MultichainContract is fully typed - you get autocomplete for:

• Contract functions available in your ABI
• Function arguments with proper types
• Return types from read operations

If you try to call a function that doesn't exist in the ABI or pass incorrect arguments, you'll get a TypeScript error at compile time.

Common Use Cases

The MultichainContract excels at scenarios like:

• Checking balances across multiple chains before initiating a transfer
• Creating complex multi-chain operations where you need to interact with the same contract on different chains
• Building interfaces that need to show data from multiple chains simultaneously
• Encoding chain-specific transactions as part of larger multi-chain workflows

The beauty of this abstraction is that it handles all the complexity of cross-chain contract interactions while presenting a clean, unified interface for your code.