megaethss-developer

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name: megaethss-developer description: 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.

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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

| 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)

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

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

Meridian payments: 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

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

Reference links & attribution: resources.md