Developer Quickstart

Deploy your first smart contract on Monolythium in 30 minutes. This guide uses Foundry and the Monolythium testnet.

Prerequisites

• A terminal with curl and git
• Basic Solidity knowledge
• An EVM wallet (MetaMask or the Monolythium Browser Wallet)

Step 1: Install Foundry

curl -L https://foundry.paradigm.xyz | bash
foundryup

Verify the installation:

forge --version
cast --version

Step 2: Create a Project

forge init my-monolythium-project
cd my-monolythium-project

Step 3: Configure for Monolythium Testnet

Replace the contents of foundry.toml:

[profile.default]
src = "src"
out = "out"
libs = ["lib"]
solc_version = "0.8.20"
optimizer = true
optimizer_runs = 200
evm_version = "paris"

[rpc_endpoints]
monolythium_testnet = "https://evm.testnet.mononodes.xyz"

[etherscan]
monolythium_testnet = { key = "", url = "https://testnet.monoscan.xyz/api", chain = 6940 }

EVM Version Must Be paris

Monolythium is an Ethermint-based chain and does not support the PUSH0 opcode. Always set evm_version = "paris". Using shanghai or later will cause deployment failures.

Step 4: Get Testnet LYTH

You need testnet LYTH to pay for gas. Visit the faucet:

1. Go to monohub.xyz/faucet
2. Connect your wallet or paste your address
3. Click Request LYTH

The faucet will send testnet LYTH to your address within seconds. See Get LYTH for more details.

Step 5: Write a Contract

Replace the contents of src/Counter.sol with a simple greeting contract:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Greeter {
    string public greeting;
    address public owner;

    event GreetingChanged(string oldGreeting, string newGreeting);

    constructor(string memory _greeting) {
        greeting = _greeting;
        owner = msg.sender;
    }

    function setGreeting(string calldata _newGreeting) external {
        require(msg.sender == owner, "only owner");
        string memory old = greeting;
        greeting = _newGreeting;
        emit GreetingChanged(old, _newGreeting);
    }
}

Build the contract:

forge build

Step 6: Deploy to Testnet

Export your private key (never commit this to source control):

export PRIVATE_KEY=your_private_key_here

Deploy with the --legacy flag (required for Monolythium):

forge create --rpc-url monolythium_testnet \
  --private-key $PRIVATE_KEY \
  --legacy \
  src/Counter.sol:Greeter \
  --constructor-args "Hello, Monolythium!"

Legacy Transactions Required

Monolythium does not support EIP-1559 dynamic fee transactions. You must use the --legacy flag for all Foundry on-chain commands (forge create, forge script, cast send).

On success, you will see output like:

Deployer: 0xYourAddress...
Deployed to: 0xYourContractAddress...
Transaction hash: 0xYourTxHash...

Save the deployed contract address for the next steps.

Step 7: Interact with Your Contract

Read the greeting:

cast call --rpc-url https://evm.testnet.mononodes.xyz \
  0xYourContractAddress \
  "greeting()(string)"

Update the greeting:

cast send --rpc-url https://evm.testnet.mononodes.xyz \
  --private-key $PRIVATE_KEY \
  --legacy \
  0xYourContractAddress \
  "setGreeting(string)" "Hello from Monolythium!"

Step 8: Verify on Monoscan

Verify the contract source code on the testnet block explorer:

forge verify-contract 0xYourContractAddress \
  src/Counter.sol:Greeter \
  --chain-id 6940 \
  --verifier-url https://testnet.monoscan.xyz/api \
  --constructor-args $(cast abi-encode "constructor(string)" "Hello, Monolythium!")

Once verified, view your contract at:

https://testnet.monoscan.xyz/address/0xYourContractAddress

Quick Reference

Item	Value
Testnet RPC	https://evm.testnet.mononodes.xyz
Chain ID	6940
EVM Version	paris
Explorer	https://testnet.monoscan.xyz
Faucet	https://monohub.xyz/faucet
Native Token	LYTH (18 decimals)
Transaction Type	Legacy only (--legacy flag)

What's Next

• Chain Configuration -- Full network parameters and wallet setup
• Hardhat & Foundry -- Advanced tooling, testing, CI/CD
• Contract Verification -- Detailed verification guide
• Smart Contract Reference -- All deployed protocol contracts