Interchain Accounts (ICAs) enable a contract on the origin chain to make authenticated calls to contracts on a remote chain. Unlike general message passing, which requires the recipient to implement a specific interface, ICAs allow interaction with any contract on the destination chain. Developers can use ICAs for cross-chain execution, enabling contracts to trigger function calls on remote chains. Each ICA on a destination chain corresponds to a unique sender on the origin chain, and the account is deterministic based on (origin, sender, router, ISM). This means that for every contract making interchain calls, there is a corresponding account on the destination chain that executes those calls. ICA is currently supported only on EVM chains.

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Architecture Overview

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How Interchain Accounts Work

Interchain Accounts allow you to make a remote call from Chain A to Chain B using the router (InterchainAccountRouter). We use CREATE2 to compute the deterministic OwnableMulticall contract address for you, which serves as a proxy for your cross-chain calls. You can explore this here. Here’s how it works:
  • You can encode your call which includes the to address, call data, and the msg.value for each call, batched together in an array.
  • You send the encoded call to the Chain A router which gets relayed to the Chain B router.
  • After decoding the calls, the Chain B router checks if the computed address is already deployed or not. If not, we deploy the OwnableMulticall contract.
  • The router then performs a multicall on the ICA address, which in turn makes the desired arbitrary call on Chain B.
The Interchain Account interface assigns every (uint32 origin, address owner, address remoteRouter, address remoteISM) tuple a unique ICA address. The sender owns that ICA on the destination chain, and can direct it to make arbitrary function calls via the InterchainAccountRouter.callRemote() endpoint. For core chains supported by Hyperlane, you are able to use the defaults that are set by the owner of the router contract. See the #overrides section to see how to make calls to any chain.

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Interface

// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity >=0.6.11;

import {CallLib} from "../contracts/libs/Call.sol";

interface IInterchainAccountRouter {
    function callRemote(
        uint32 _destinationDomain,
        CallLib.Call[] calldata calls
    ) external returns (bytes32);

    function getRemoteInterchainAccount(uint32 _destination, address _owner)
        external
        view
        returns (address);
}
  • Use InterchainAccountRouter out of the box - ICA routers have already been deployed to core chains. Please refer to addresses. Try using the callRemote method to do a call via your wallet’s interchain account.