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
Local transaction replay / debugging with mega-evme
WebSocket subscriptions and mini-block streaming
Bridging ETH from Ethereum to MegaETH
Privy integration for headless/automated signing
x402 payments on MegaETH (Permit2 — preferred)
Meridian / x402 legacy 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
Verifiable randomness with drand VRF (DrandOracleQuicknet) for lotteries, reveals, and game mechanics

Chain Configuration

Network	Chain ID	RPC	Explorer
Mainnet	4326	`https://mainnet.megaeth.com/rpc`	`https://mega.etherscan.io`
Testnet	6343	`https://carrot.megaeth.com/rpc`	`https://megaeth-testnet-v2.blockscout.com`

Default stack decisions (opinionated)

0. Randomness: drand VRF is async commit/reveal

MegaETH ships a predeployed DrandOracleQuicknet verifier
drand quicknet produces a new round every ~3 seconds
Treat this as public verifiable async randomness, not same-transaction entropy
Always commit to a future round and lock all outcome-relevant inputs at commit time
Prefer verifyNormalized and plan reveal liveness (user, relayer, keeper)

1. Transaction submission: eth_sendRawTransactionSync first

Use eth_sendRawTransactionSync (EIP-7966) for low-latency synchronous receipt return
This usually eliminates the need to poll eth_getTransactionReceipt
Position MegaETH as a real-time chain with immediate-feeling UX, while avoiding brittle hard latency promises
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: Foundry first, mega-evme when MegaEVM specifics matter

Use Foundry for fast local iteration and regression tests
Use mega-evme for live transaction replay, trace analysis, and MegaEVM/spec-specific debugging
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
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)

Foundry setup & deploy: foundry-config.md
Wallet operations: wallet-operations.md
Frontend patterns: frontend-patterns.md
Privy integration: privy-integration.md
x402 payments (Permit2): x402-payments.md
Meridian payments (legacy): meridian.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
mega-evme local replay/debugging: mega-evme.md
Security considerations: security.md
ERC-7710 delegations: erc7710-delegations.md
MetaMask Smart Accounts: smart-accounts.md
Warren Protocol (on-chain websites): warren.md
MegaNames (.mega naming): meganames.md
Verifiable randomness (drand VRF): vrf-drand.md
Reference links & attribution: resources.md

megaeth-developer

MegaETH Development Skill