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megaethss-developer

Dev Tools

End-to-end MegaETH development playbook (Feb 2026). Covers Foundry project setup with MegaETH-specific config, wallet operations, token swaps (Kyber Network), eth_sendRawTransactionSync (EIP-7966) for instant receipts, JSON-RPC batching, real-time mini-block subscriptions, storage-aware contract patterns (Solady RedBlackTreeLib, transient storage), MegaEVM multidimensional gas model, WebSocket keepalive, bridging from Ethereum, Privy headless signing for ultra-low latency, debugging with mega-evme, Meridian x402 payments on MegaETH (seller-side settlement plus buyer-side USDm forwarder approvals and EIP-712 authorizations), and Warren Protocol for on-chain website hosting. Use when building on MegaETH, using Foundry, managing wallets, sending transactions, deploying contracts, integrating Privy embedded wallets, ERC-7710 delegation framework for scoped on-chain permissions, MetaMask Smart Accounts Kit for smart account creation and delegation management, integrating Meridian/x402 paid APIs or agent actions, hosting websites on-chain with Warren, or integrating MegaNames (.mega naming service) for name registration, resolution, subdomains, subdomain marketplace (selling/buying subdomains with token gating), and text records.

Install

openclaw skills install megaethss-developer

MegaETH Development Skill

What this Skill is for

Use this Skill when the user asks for:

  • Foundry project setup targeting MegaETH
  • Writing and running tests (unit, fuzz, invariant) on MegaETH
  • Deploying and verifying contracts on MegaETH
  • Wallet setup and management on MegaETH
  • Sending transactions, checking balances, token operations
  • Token swaps via Kyber Network aggregator
  • MegaETH dApp frontend (React / Next.js with real-time updates)
  • RPC configuration and transaction flow optimization
  • Smart contract development with MegaEVM considerations
  • Storage optimization (transient storage, Solady patterns)
  • Gas estimation and fee configuration
  • Testing and debugging MegaETH transactions
  • WebSocket subscriptions and mini-block streaming
  • Bridging ETH from Ethereum to MegaETH
  • Privy integration for headless/automated signing
  • Meridian / x402 payments on MegaETH
  • Ultra-low latency transaction patterns
  • ERC-7710 delegations (scoped permissions, spending limits, redelegation chains)
  • MetaMask Smart Accounts (ERC-4337 accounts, signers, user operations)
  • Advanced permissions (ERC-7715) via MetaMask
  • MegaNames (.mega naming service) — registration, resolution, subdomains, subdomain marketplace, text records

Chain Configuration

NetworkChain IDRPCExplorer
Mainnet4326https://mainnet.megaeth.com/rpchttps://mega.etherscan.io
Testnet6343https://carrot.megaeth.com/rpchttps://megaeth-testnet-v2.blockscout.com

Default stack decisions (opinionated)

1. Transaction submission: eth_sendRawTransactionSync first

2. RPC: Multicall for eth_call batching (v2.0.14+)

  • Prefer Multicall (aggregate3) for batching multiple eth_call requests
  • As of v2.0.14, eth_call is 2-10x faster; Multicall amortizes per-RPC overhead
  • Still avoid mixing slow methods (eth_getLogs) with fast ones in same request

Note: Earlier guidance recommended JSON-RPC batching over Multicall for caching benefits. With v2.0.14's performance improvements, Multicall is now preferred.

3. WebSocket: keepalive required

  • Send eth_chainId every 30 seconds
  • 50 connections per VIP endpoint, 10 subscriptions per connection
  • Use miniBlocks subscription for real-time data

4. Storage: slot reuse patterns

  • SSTORE 0→non-zero costs 2M gas × multiplier (expensive)
  • Use Solady's RedBlackTreeLib instead of Solidity mappings
  • Design for slot reuse, not constant allocation

5. Gas: skip estimation when possible

  • Base fee stable at 0.001 gwei, no EIP-1559 adjustment
  • Ignore eth_maxPriorityFeePerGas (returns 0)
  • Hardcode gas limits to save round-trip
  • Always use remote eth_estimateGas (MegaEVM costs differ from standard EVM)

6. Debugging: mega-evme CLI

Operating procedure

1. Classify the task layer

  • Frontend/WebSocket layer
  • RPC/transaction layer
  • Smart contract layer
  • Testing/debugging layer

2. Pick the right patterns

  • Frontend: single WebSocket → broadcast to users (not per-user connections)
  • Transactions: sign locally → eth_sendRawTransactionSync → done
  • Contracts: check SSTORE patterns, avoid volatile data access limits
  • Testing: use mega-evme for replay, Foundry with --skip-simulation
  • Delegations: create scoped permissions → sign → share → redeem via eth_sendRawTransactionSync

3. Implement with MegaETH-specific correctness

Always be explicit about:

  • Chain ID (4326 mainnet, 6343 testnet)
  • Gas limit (hardcode when possible)
  • Base fee (0.001 gwei, no buffer)
  • Storage costs (new slots are expensive)
  • Volatile data limits (20M total compute gas cap, retroactive, when block.timestamp accessed)

4. Deliverables expectations

When implementing changes, provide:

  • Exact files changed + diffs
  • Commands to build/test/deploy
  • Gas cost notes for storage-heavy operations
  • RPC optimization notes if applicable

Progressive disclosure (read when needed)

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