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Documentation

The contents of the Custom Proxy page block you are viewing are primarily for informational purposes. For complete details on Custom Proxy development, please refer to the official documentation linked below:

Custom Proxy

Developer documentation within @tonappchain/evm-ccl NPM-package
You can also reach out to our developer community in Telegram or Discord.

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Installation

Setting up TAC Proxy development requires installing the TAC cross-chain libraries and configuring your Solidity development environment. TAC Proxy development currently requires Hardhat. Foundry support is planned in future. 
npm install --save @tonappchain/evm-ccl@latest

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Hardhat Environment Setup

Ensure your Hardhat project includes the necessary dependencies:
package.json
{
  "devDependencies": {
    "@nomicfoundation/hardhat-toolbox": "^5.0.0",
    "hardhat": "^2.22.5",
    "ethers": "^6.13.2",
    "chai": "^4.3.7",
    "ts-node": "^10.9.2",
    "typescript": "^5.6.3",
    "@tonappchain/evm-ccl": "^latest"
  }
}
Configure your hardhat.config.js for TAC networks:
hardhat.config.js
require("@nomicfoundation/hardhat-toolbox");

module.exports = {
  solidity: {
    version: "0.8.28",
    settings: {
      optimizer: {
        enabled: true,
        runs: 200,
      },
    },
  },
  networks: {
    tac_testnet: {
      url: "https://spb.rpc.tac.build",
      chainId: 2391,
      accounts: [process.env.PRIVATE_KEY || ""],
      gasPrice: 20000000000,
    },
    tac_mainnet: {
      url: "https://rpc.tac.build", 
      chainId: 239,
      accounts: [process.env.PRIVATE_KEY || ""],
      gasPrice: 20000000000,
    },
  },
};

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Project Structure Setup

Create an organized project structure for proxy development:

Create Contract Directory

Organize your contracts with clear separation between proxy and application logic:
contracts/
├── proxies/          # TAC proxy contracts
│   ├── MyProxy.sol
│   └── MyNFTProxy.sol
├── interfaces/       # Custom interfaces
│   └── IMyDApp.sol
├── libraries/        # Utility libraries
└── mocks/           # Testing contracts
    ├── TestToken.sol
    └── TestNFT.sol

Setup Testing Environment

Create a test directory with proper organization:
test/
├── proxies/          # Proxy-specific tests
│   ├── MyProxy.test.ts
│   └── NFTProxy.test.ts
├── integration/      # Cross-chain integration tests
└── helpers/         # Test utilities
    └── tacTestHelpers.ts

Configure Environment Variables

Create a .env file for sensitive configuration:
.env
# Deployment
PRIVATE_KEY=your_private_key_here

# Network Configuration
TAC_TESTNET_RPC=https://spb.rpc.tac.build
TAC_MAINNET_RPC=https://rpc.tac.build

# Optional: API Keys
ETHERSCAN_API_KEY=your_etherscan_api_key
Never commit your .env file. Add it to your .gitignore immediately.

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Verify Installation

Create a basic proxy contract to verify your setup:
contracts/TestProxy.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.28;

import { TacProxyV1 } from "@tonappchain/evm-ccl/contracts/proxies/TacProxyV1.sol";
import { TacHeaderV1 } from "@tonappchain/evm-ccl/contracts/core/Structs.sol";

contract TestProxy is TacProxyV1 {
    event MessageReceived(address indexed caller, string message);
    
    constructor(address crossChainLayer) TacProxyV1(crossChainLayer) {}
    
    function receiveMessage(bytes calldata tacHeader, bytes calldata arguments)
        external
        _onlyCrossChainLayer
    {
        TacHeaderV1 memory header = _decodeTacHeader(tacHeader);
        string memory message = abi.decode(arguments, (string));
        
        emit MessageReceived(header.tvmCaller, message);
    }
}
Compile to verify setup: 
npx hardhat compile
If compilation succeeds, your environment is properly configured for TAC Proxy development.

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Common Setup Issues

Problem: Import resolution failures or compilation errorsSolutions:
  • Ensure @tonappchain/evm-ccl is properly installed
  • Verify Solidity version compatibility (0.8.28+)
  • Check import paths are correct
  • Reset and reinstall dependencies: 
    rm -rf node_modules package-lock.json
npm install
  • Clean and rebuild: 
    npx hardhat clean && npx hardhat compile
Problem: Unable to connect to TAC networkSolutions:
  • Verify RPC URLs are correct
  • Check network configuration in hardhat.config.js
  • Test connection manually: curl https://spb.rpc.tac.build
  • Ensure firewall allows outbound connections
// Test network connectivity
const { ethers } = require("hardhat");
async function testConnection() {
  const provider = new ethers.JsonRpcProvider("https://spb.rpc.tac.build");
  const blockNumber = await provider.getBlockNumber();
  console.log("Connected! Latest block:", blockNumber);
}
Problem: Deployment fails with account/key errorsSolutions:
  • Verify private key is in .env file
  • Ensure private key starts with 0x if required by your configuration
  • Check that the account has sufficient TAC tokens for deployment. Get them here

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What’s Next?

Environment ready? Let’s get to examples:

Basic Proxy Example