Tooling configuration

Set up Foundry, viem, wagmi, Hardhat, and ethers.js for Radius

Radius uses a fixed gas price model, which requires specific configuration in some tools. This page covers setup for each major EVM development tool. For background on how Radius differs from Ethereum, see Ethereum compatibility.

At a glance

Tool	Configuration needed	Notes
Foundry	`foundry.toml` with `gas_price`, `evm_version`, `via_ir`	`--broadcast` required for `forge create`
viem	`defineChain()` — no overrides needed	Fee estimation works out of the box
wagmi	Use custom Radius chain definition in `createConfig`	—
Hardhat	Pin to v2, set `gasPrice` in network config	v3 installs by default and is incompatible
ethers.js	None — works out of the box	Handles gas pricing gracefully without overrides

Foundry

Recommended `foundry.toml`

Add these settings to your project's foundry.toml:

[profile.default]
gas_price = 1000000000
evm_version = "cancun"
via_ir = true

Setting	Purpose
`gas_price`	Matches Radius's fixed gas price (~1 gwei). Query `eth_gasPrice` for the exact value. Eliminates the need for `--gas-price` on every CLI command.
`evm_version`	Targets the EVM version Radius supports.
`via_ir`	Uses the IR-based code generator. Required for complex deploy scripts with many contracts to avoid "Stack too deep" errors.

CLI usage

Deploy a contract:

forge create src/MyContract.sol:MyContract \
  --rpc-url https://rpc.testnet.radiustech.xyz \
  --account radius-deployer \
  --broadcast

Send a transaction with cast:

cast send --gas-price 1000000000 \
  --rpc-url https://rpc.testnet.radiustech.xyz \
  --account radius-deployer \
  {{CONTRACT_ADDRESS}} "transfer(address,uint256)" {{WALLET_ADDRESS}} 1000000

viem

Chain definition

Radius uses fixed gas pricing. Standard defineChain() works out of the box — viem queries eth_maxPriorityFeePerGas and eth_gasPrice automatically:

import { defineChain } from 'viem';
 
export const radiusMainnet = defineChain({
  id: 723487,
  name: 'Radius Network',
  nativeCurrency: { decimals: 18, name: 'RUSD', symbol: 'RUSD' },
  rpcUrls: {
    default: { http: ['https://rpc.radiustech.xyz'] },
  },
  blockExplorers: {
    default: {
      name: 'Radius Explorer',
      url: 'https://network.radiustech.xyz',
    },
  },
});
 
export const radiusTestnet = defineChain({
  id: 72344,
  name: 'Radius Testnet',
  nativeCurrency: { decimals: 18, name: 'RUSD', symbol: 'RUSD' },
  rpcUrls: {
    default: { http: ['https://rpc.testnet.radiustech.xyz'] },
  },
  blockExplorers: {
    default: {
      name: 'Radius Testnet Explorer',
      url: 'https://testnet.radiustech.xyz',
    },
  },
});

Use this chain definition with createPublicClient and createWalletClient:

import { createPublicClient, createWalletClient, http } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';
import { radiusTestnet } from './chain';
 
const publicClient = createPublicClient({
  chain: radiusTestnet,
  transport: http(),
});
 
const walletClient = createWalletClient({
  account: privateKeyToAccount('0x...'),
  chain: radiusTestnet,
  transport: http(),
});

wagmi integration

Use the custom chain definition with wagmi's createConfig:

import { http, createConfig } from 'wagmi';
import { radiusTestnet } from './chain';
 
export const config = createConfig({
  chains: [radiusTestnet],
  transports: {
    [radiusTestnet.id]: http(),
  },
});

Then use standard wagmi hooks in your React components:

import { useWriteContract, useWaitForTransactionReceipt } from 'wagmi';
 
function SendPayment() {
  const { writeContract, data: hash } = useWriteContract();
  const { isSuccess } = useWaitForTransactionReceipt({ hash });
 
  return (
    <button
      onClick={() =>
        writeContract({
          address: contractAddress,
          abi: contractAbi,
          functionName: 'transfer',
          args: [recipient, amount],
        })
      }
    >
      {isSuccess ? 'Sent' : 'Send'}
    </button>
  );
}

Hardhat

Version pinning

Hardhat v3 installs by default and uses ESM, which is incompatible with many existing plugins. Pin to v2:

pnpm add -D hardhat@^2.22.0 @nomicfoundation/hardhat-toolbox@hh2

Network configuration

Add Radius to your hardhat.config.ts:

import { HardhatUserConfig } from 'hardhat/config';
import '@nomicfoundation/hardhat-toolbox';
 
const config: HardhatUserConfig = {
  solidity: '0.8.24',
  networks: {
    radiusTestnet: {
      url: 'https://rpc.testnet.radiustech.xyz',
      chainId: 72344,
      gasPrice: 1000000000,
      accounts: [process.env.PRIVATE_KEY!],
    },
  },
};
 
export default config;

Deploy with:

pnpm hardhat run scripts/deploy.ts --network radiusTestnet

ethers.js

ethers.js handles Radius's gas pricing out of the box with no overrides. When baseFeePerGas is 0x0, ethers.js returns maxFeePerGas: null and falls back to legacy gasPrice automatically.

import { ethers } from 'ethers';
 
const provider = new ethers.JsonRpcProvider('https://rpc.testnet.radiustech.xyz');
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY!, provider);
 
// Standard transaction — no gas override needed
const tx = await wallet.sendTransaction({
  to: recipient,
  value: ethers.parseEther('1.0'),
});
await tx.wait();