System Architecture Overview

Evently — The Pulse of Truth. Built on MegaETH.

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Stack

Layer	Technology
Smart contracts	Solidity 0.8.20, Hardhat, MegaETH Chain ID 4326
Auth & wallets	Privy (email, social, embedded wallets, smart accounts)
Account abstraction	ERC-4337 (Privy Kernel smart wallets + Pimlico bundler/paymaster)
Session keys	MetaMask Delegation Toolkit pattern (EIP-712 delegations)
Real-time	MegaETH WebSocket (eth_subscribe, eth_sendRawTransactionSync)
Frontend	Next.js 14, Tailwind CSS, wagmi, viem, Supabase
Base token	USDM (0xFAfDdbb3FC7688494971a79cc65DCa3EF82079E7)

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Architecture Diagram

┌───────────────────────────────────────────────────────┐
│                    USER                                │
│         (browser — no wallet extension needed)         │
└──────────────────────┬────────────────────────────────┘
                       │ email / Google / Twitter / Discord
                       ▼
┌──────────────────────────────────────────────────────┐
│               PRIVY AUTH LAYER                        │
│  Email OTP · Google · Twitter · Discord · GitHub      │
│                                                       │
│  Auto-creates:  Embedded Wallet (EOA)                 │
│  Wraps in:      Kernel Smart Account (ERC-4337)        │
└──────────────────────┬───────────────────────────────┘
                       │
       ┌───────────────┼───────────────┐
       │               │               │
       ▼               ▼               ▼
 READ PATH       WRITE PATH      SESSION PATH
(multicall)     (gasless tx)    (no popup/trade)
       │               │               │
       ▼               ▼               ▼
 HTTP+Multicall3  UserOperation   Session Key Tx
 2s TTL cache      via Bundler    (pre-delegated)
       │               │               │
       └───────┬───────┘───────────────┘
               ▼
      ┌──────────────────┐
      │    PAYMASTER     │
      │   (Pimlico)      │
      │  sponsors gas    │
      │  rate-limited    │
      └────────┬─────────┘
               ▼
      ┌───────────────────────────────────┐
      │     EventlyMarkets.sol          │
      │     MegaETH Chain ID 4326         │
      │                                   │
      │  placeOrder / sellToAMM           │
      │  createMarket / resolveMarket      │
      │  claimRewards / cancelOrder       │
      └──────────────────┬────────────────┘
                         │ events
                         ▼
      ┌────────────────────────────────────┐
      │   MegaETH WebSocket               │
      │   wss://mainnet.megaeth.com/ws     │
      │                                   │
      │   mini-blocks ~10 ms              │
      │   eth_sendRawTransactionSync      │
      │   watchContractEvent              │
      └──────────────────┬────────────────┘
                         │
                         ▼
      ┌────────────────────────────────────┐
      │   FRONTEND REALTIME ENGINE        │
      │   Instant confirmation (~10 ms)   │
      │   Live odds · Live order book     │
      │   No page refresh                 │
      └────────────────────────────────────┘

---

Gas Sponsorship Flow

User triggers trade
  → sendGasless() checks shouldSponsor()
  → Privy packs UserOperation
  → Pimlico Paymaster signs (verifies whitelist + rate limit)
  → Pimlico Bundler submits to MegaETH
  → EventlyMarkets executes
  → Receipt returned synchronously via eth_sendRawTransactionSync
  → UI updates within ~10 ms

Sponsored functions: placeOrder, sellToAMM, createMarket, resolveMarket, claimRewards, approve (USDM)

---

Session Key Flow

User clicks "Session" → one wallet popup
  → generatePrivateKey() — ephemeral key
  → smartWallet.signMessage(delegation)
    { sessionKey, selectors, contract, expiresAt, maxCalls }
  → stored in sessionStorage

Per trade (no popup):
  → tradeWithSession() — validates session
  → submits with session key context
  → up to 100 trades before session expires

---

Security Controls

Control	Value
Paymaster contract whitelist	EventlyMarkets + USDM only
Sponsored selectors	6 core functions only
Rate limit	20 user ops / min / wallet
Spend cap	1 ETH equivalent / hour / wallet
Spam threshold	15 ops in 10 s → blocked
RPC failover	2 endpoints, health-checked

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Smart Contract Audit Result

EventlyMarkets.sol — no changes required for ERC-4337 compatibility.

• No tx.origin
• No extcodesize / EOA checks
• msg.sender used generically
• Compatible with smart account callers