How to Deploy Smart Contracts on Hedera Using Truffle

Aug 09, 2022

by Ed Marquez

Developer Evangelist

The Hedera JSON RPC Relay enables developers to use their favorite EVM-compatible tools such as Truffle, Hardhat, Web3JS, EthersJS, to deploy and interact with smart contracts on the Hedera network. As highlighted in a previous article, the relay provides applications and tools seamless access to Hedera while masking implementation complexities and preventing reductions in performance, security, and scalability.

This tutorial shows you how to deploy smart contracts on Hedera using Truffle and the JSON RPC Relay with the following steps:

Create an account that has ECDSA keys using the Javascript SDK
Compile a contract using Truffle
Deploy the smart contract to Hedera network through the JSON RPC Relay

You can find more examples using Truffle, Web3JS, and Hardhat in this GitHub repository.

Try It Yourself

Name: Hedera
Price range: $

Get a Hedera testnet account
This Codesandbox is already setup for you to try this example
- Fork the sandbox
- Remember to provide your testnet account credentials for the operator in the .env file
- Open a new terminal and run:
  - npm install -g truffle (this installation may take a few minutes)
  - node create-account.js
Get the example code from GitHub

1. Grab Your ECDSA Keys from the Hedera Portal

Hedera supports two popular types of signature algorithms, ED25519 and ECDSA. Both are used in many blockchain platforms including Bitcoin and Ethereum. Currently, the JSON RPC Relay only supports Hedera accounts with an alias set (i.e. public address) based on its ECDSA public key.

To deploy a smart contract using Truffle, go to the Hedera portal, create a free Testnet account (if you haven't already), and copy the HEX Encoded Private Key for your account with ECDSA keys. Next, paste that value into the ETH_PRIVATE_KEY variable in the .env file (if you cloned the repository, you may need to rename the file from .env_sample to .env).

IMPORTANT NOTE: Private keys for Testnet are displayed here for educational purposes only. Never share your private key(s) with others, as that may result in lost funds, or loss of control over your account.

In case you’re interested in more details about auto account creation and alias, check out the documentation and HIP-32.

2. Compile a Smart Contract Using Truffle

Now it’s time to compile SimpleStorage, which is a basic smart contract that allows anyone to set and get data.

// SPDX-License-Identifier: MIT
pragma solidity >=0.4.22 <0.9.0;

contract SimpleStorage {
   uint256 data;

   function getData() external view returns (uint256) {
       return data;
   }

   function setData(uint256 _data) external {
       data = _data;
   }
}

Use the following command to perform the compilation:

truffle compile

Console Output:

2022 How to Deploy Smart Contracts on Hedera Using Truffle Image 2

3. Deploy the Smart Contract to Hedera Using Truffle

Finally, deploy the contract on Hedera through the JSON RPC Relay. Be sure to configure the following parameters in your .env file to be able to deploy to the Hedera testnet with Truffle.

NETWORK_ID = 296
JSON_RPC_RELAY_URL = https://testnet.hashio.io/api
ETH_PRIVATE_KEY = 0x7a9e... [Paste value of “HEX Encoded Private Key”]

This example uses the Hashio instance of the JSON RPC Relay, hosted by Swirlds Labs. URLs are also available for the Hedera Mainnet and Previewnet.

Deploy the contract with the following command:

truffle migrate

Console Output:

2022 How to Deploy Smart Contracts on Hedera Using Truffle Image 3

You can obtain more information about the newly deployed contract by using the mirror node REST API. Additional context for that API is provided in this blog post. Based on the console output of the example above, here are two mirror node queries that provide more information about the new contract and account based on their respective Solidity addresses:

Now you know how to deploy smart contracts on Hedera using Truffle and the JSON RPC Relay. The first part of this example used the Hedera JavaScript SDK. However, you can try this with the other officially supported SDKs for Java and Go.

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