radius-dev

name: radius-dev description: End-to-end Radius Network development playbook. Stablecoin-native EVM with sub-second finality and 2.5M TPS. Uses @radiustechsystems/sdk (viem-native) with radiusWalletActions() decorator for wallet clients. wagmi for React wallet integration. Foundry for smart contract development and testing. Covers micropayment patterns (pay-per-visit content, real-time API metering, streaming payments), stablecoin-native fees via Turnstile, batch transactions, ERC-20 operations, SDK event watching, and EVM compatibility differences from Ethereum. user-invocable: true

Radius Development Skill

What this Skill is for

Use this Skill when the user asks for:

• Radius dApp UI work (React / Next.js with wagmi)
• Wallet connection + transaction signing on Radius
• Smart contract deployment to Radius (Foundry / Solidity)
• Micropayment patterns (pay-per-visit content, API metering, streaming payments)
• Radius SDK usage (TypeScript, events, batch transactions)
• EVM compatibility questions specific to Radius
• Stablecoin-native fee model and Turnstile mechanism
• Radius network configuration, RPC endpoints, contract addresses

Default stack decisions (opinionated)

1. SDK: @radiustechsystems/sdk + viem

• Built natively on viem. Extends wallet clients with radiusWalletActions().
• Use createPublicClient for reads, createWalletClient for writes.
• Always call .extend(radiusWalletActions()) on wallet clients for Radius features (batch transactions, optimized gas estimation).

2. UI: wagmi + @tanstack/react-query for React apps

• Import radiusTestnet chain from @radiustechsystems/sdk.
• Use injected() connector for MetaMask and EIP-1193 wallets.
• Standard wagmi hooks: useAccount, useConnect, useSendTransaction, useWaitForTransactionReceipt.

3. Smart contracts: Foundry

• forge create for direct deployment, forge script for scripted deploys.
• cast call for reads, cast send for writes.
• OpenZeppelin for standard patterns (ERC-20, ERC-721, access control).
• Solidity 0.8.x, Osaka hardfork support via Revm 33.1.0.

4. Chain: Radius Testnet

• Chain ID: 72344
• RPC: https://rpc.testnet.radiustech.xyz
• Native currency: RUSD (18 decimals)
• Fee token (radUSD): 0xF966020a30946A64B39E2e243049036367590858
• Faucet: https://testnet.radiustech.xyz/testnet/faucet

5. Fees: Stablecoin-native via Turnstile

• Users pay gas in stablecoins (USD). No separate gas token needed.
• Fixed cost: ~0.0001 USD per transaction (10,000 txs per 1 USD).
• eth_gasPrice returns 0x0. Wallets and tooling work normally.
• Failed transactions do NOT charge gas.

Critical Radius differences from Ethereum

Always keep these in mind when writing code for Radius:

Solidity patterns to watch:

// DON'T — always returns 0 on Radius
require(address(this).balance > 0);

// DO — use ERC-20 balance instead
require(IERC20(feeToken).balanceOf(address(this)) > 0);

Standard ERC-20 interactions, storage operations, and events work unchanged.

Operating procedure (how to execute tasks)

1. Classify the task layer

• UI/wallet layer — React components, wallet connection, transaction UX
• SDK/scripts layer — Backend scripts, server-side verification, event monitoring
• Smart contract layer — Solidity contracts, deployment, testing
• Micropayment layer — Pay-per-visit, API metering, streaming payments

2. Pick the right building blocks

• UI: wagmi + radiusTestnet chain + React hooks
• Scripts/backends: @radiustechsystems/sdk + viem directly
• Smart contracts: Foundry (forge / cast) + OpenZeppelin
• Micropayments: Combine SDK + server-side verification + wallet integration

3. Implement with Radius-specific correctness

Always be explicit about:

• Using radiusTestnet chain definition from the SDK
• Extending wallet clients with radiusWalletActions()
• Stablecoin fee model (no ETH needed, no gas price bidding)
• Instant finality (no need to wait for multiple confirmations)
• Using parseEther for USD amounts (18 decimals, same as ETH)
• Environment variables for private keys (never hardcode)

4. Test

• Smart contracts: forge test locally, then deploy to Radius Testnet
• SDK scripts: Run against testnet RPC with funded test accounts
• Get testnet tokens from https://testnet.radiustech.xyz/testnet/faucet
• Verify deployments: cast code <address> --rpc-url https://rpc.testnet.radiustech.xyz

5. Deliverables expectations

When you implement changes, provide:

• Exact files changed + diffs (or patch-style output)
• Commands to install dependencies, build, and test
• A short "risk notes" section for anything touching signing, fees, payments, or token transfers

Progressive disclosure (read when needed)

• TypeScript SDK reference: sdk-typescript.md
• Event watching + historical queries: sdk-events.md
• Smart contract deployment (Foundry): smart-contracts.md
• Wallet integration (wagmi / viem / MetaMask): wallet-integration.md
• Micropayment patterns: micropayments.md
• EVM differences + Turnstile + architecture: evm-differences.md
• Network config + contract addresses + RPC reference: network-config.md
• Security checklist: security.md
• Curated reference links: resources.md