MegaETH Development Skill

What this Skill is for

Use this Skill when the user asks for:

• 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 (avoiding expensive SSTORE costs)

• Gas estimation and fee configuration

• Testing and debugging MegaETH transactions

• WebSocket subscriptions and mini-block streaming

• Bridging ETH from Ethereum to MegaETH

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)

• Wallet operations: wallet-operations.md

• Frontend patterns: frontend-patterns.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: resources.md