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
• •Ultra-low latency transaction patterns

Chain Configuration

Default stack decisions (opinionated)

1. Transaction submission: eth_sendRawTransactionSync first

• •Use eth_sendRawTransactionSync (EIP-7966) — returns receipt in <10ms
• •Eliminates polling for eth_getTransactionReceipt
• •Docs: https://docs.megaeth.com/realtime-api

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

• •Replay transactions with full traces
• •Profile gas by opcode
• •https://github.com/megaeth-labs/mega-evm

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

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 gas after block.timestamp access)

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)

• •Foundry setup & deploy: foundry-config.md
• •Wallet operations: wallet-operations.md
• •Frontend patterns: frontend-patterns.md
• •Privy integration: privy-integration.md
• •RPC methods reference: rpc-methods.md
• •Smart contract patterns: smart-contracts.md
• •Storage optimization: storage-optimization.md
• •Gas model: gas-model.md
• •Testing & debugging: testing.md
• •Security considerations: security.md
• •Reference links & attribution: resources.md