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Omnichain Contracts
System contract

System contract

To make your life easier we already deployed a system contract with some information you may need in your protocol. You can import this code into your project and instance with the deployed address. You can find the up-to-date address of the system contract using the ZetaChain's API:

https://zetachain-athens.blockpi.network/lcd/v1/public/zeta-chain/zetacore/fungible/system_contract

In this contract you will find:

  • wZetaContractAddress: ZRC20 version of Zeta Native Token
  • uniswapv2FactoryAddress and uniswapv2Router02Address: Uniswap v2 already deployed on zEVM
  • gasZetaPoolByChainId and gasCoinZRC20ByChainId: helpers with ZRC20 data indexed by chain ID
  • gasPriceByChainId: helper to estimate gas for an external transaction
SystemContract.sol
contract SystemContract is SystemContractErrors {
    mapping(uint256 => uint256) public gasPriceByChainId;
    mapping(uint256 => address) public gasCoinZRC20ByChainId;
    mapping(uint256 => address) public gasZetaPoolByChainId;

    address public constant FUNGIBLE_MODULE_ADDRESS = 0x735b14BB79463307AAcBED86DAf3322B1e6226aB;
    address public immutable uniswapv2FactoryAddress;
    address public immutable uniswapv2Router02Address;
    address public wZetaContractAddress;
    address public zetaConnectorZEVMAddress;
    //...
}

Source: SystemContract.sol

Let's look at an example of how to use the system contract in your smart contract.

Install the protocol contracts package:

yarn add --dev @zetachain/protocol-contracts

Import the system contract and create a reference to the system contract in the constructor:

Contract.sol
// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

import "@zetachain/protocol-contracts/contracts/zevm/SystemContract.sol";

contract SystemContractSample {
    SystemContract public immutable systemContract;

    constructor(address systemContractAddress) {
        systemContract = SystemContract(systemContractAddress);
    }

    function getZRC20AddressByChainId(uint32 targetZRC20ChainId) public returns(address) {
        return systemContract.gasCoinZRC20ByChainId(targetZRC20ChainId);
    }
}

In your deploy script, you can get the system contract address by using the getAddress helper function.

import { getAddress } from "@zetachain/protocol-contracts";

const SYSTEM_CONTRACT = getAddress("systemContract", "zeta_testnet");

For an example of how the system contract can be used, please, refer to the Swap example project.