Build on Testnet

HeLa Chain Developer Quickstart Guide

If you have developed dApps on Ethereum or any EVM compatible chain before, you will feel at home. It is exactly the same. But if you are new, don’t worry, this document will help you embark on your first dApp development on HeLa chain.

Please, keep in mind we currently only support 0.8.9 solidity version.

Prerequisites

1. Remix IDE

• Open this in your browser: https://remix.ethereum.org

1. HeLa Testnet Wallet + Tokens

• Use MetaMask or any EVM wallet.

• Add HeLa Testnet RPC:

  Network name	HeLa Testnet
  RPC	https://testnet-rpc.helachain.com
  Chain ID	666888
  SYMBOL	HLUSD
  Block Explorer	https://testnet-blockexplorer.helachain.com

• Get test tokens from the Faucet To fund your wallet with transaction gas fee, go to HeLa Testnet Faucet. You will receive 10 HLUSD every 24 hours. Claim HLUSD Testnet Faucet: https://testnet-faucet.helachain.com

1. Switch MetaMask to HeLa Testnet

Step 1: Write the Smart Contract

We’ll start with a Hello World Contract.

1. Open Remix

2. Create a new file: HelloHeLa.sol

3. Paste this code:

Please, keep in mind we currently only support 0.8.9 solidity version.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

contract HelloHeLa {
    string public message;

    constructor(string memory _msg) {
        message = _msg;
    }

    function setMessage(string memory _msg) public {
        message = _msg;
    }

    function getMessage() public view returns (string memory) {
        return message;
    }
}

1. Save it.

Step 2: Compile the Contract

1. In Remix, go to the Solidity Compiler tab

2. Click Compile HelloHeLa.sol

   • If no errors, you’re good to go.

Step 3: Deploy to HeLa Testnet

1. Go to Deploy & Run Transactions tab

2. Change Environment to Injected Provider - MetaMask (it will auto-connect your wallet)

3. Make sure MetaMask is set to HeLa Testnet

4. Under Contract, select HelloHeLa

5. Add "Hello from HeLa!" in the constructor input

6. Click Deploy

7. Approve the transaction in MetaMask

Your contract is now live on HeLa Testnet!

Step 4: Interact with Your Contract

1. After deploying, Remix will show a panel with your contract.

2. Click getMessage — it should return "Hello from HeLa!"

3. Try setMessage("Welcome to HeLa")

4. Call getMessage again to see the updated message.

Step 5: Verify on HeLa Explorer (Optional)

1. Copy your contract address from Remix

2. Open https://testnet-blockexplorer.helachain.com/

Transaction and smart contracts can be observed and verfied in Testnet Block Explorer.

1. Paste the address and see your live contract

Build more, explore contracts, and join the HeLa Developer Discord for help and ideas!