MEV Blocker

WHAT IT DOES

MEV Blocker gives DeFi traders and protocol users real-time insight into potential MEV (Maximal Extractable Value) risks affecting their transactions. It reads live on-chain data including mempool pending transactions, public transaction pool state, gas price oracles, block state, transaction simulation data, and sandwich attack indicators. You can analyze any transaction hash for MEV activity, detect sandwich attacks, front-running, and back-running attempts, and assess overall MEV risk levels. The tool shows you in real time whether your transaction is at risk, what type of MEV attack may be occurring, and how much MEV profit was extracted—so you can avoid becoming a victim of MEV bots.

HOW TO USE

Connect your EVM wallet (optional—the tool can work in read-only mode). Enter a transaction hash to analyze for MEV activity, or use the simulation feature to test a transaction before sending it. Click "Analyze for MEV" to fetch current data from the chain and run heuristics against the transaction. The tool displays the transaction hash, MEV risk level (Low/Medium/High), sandwich attack detection, front-running detection, back-running detection, MEV profit extracted, current gas price, pending transaction count, and block number. A visual dashboard shows the MEV score, transaction logs, and gas used. The simulation feature lets you test any contract call for potential MEV vulnerabilities before executing it.

TECHNICAL APPROACH

This tool queries live blockchain and mempool state using ethers v5.7.2. It fetches transaction data and receipts using getTransaction() and getTransactionReceipt(). It analyzes calldata for known swap patterns and DEX interaction signatures that are commonly targeted by MEV bots. It checks gas price relative to the network average—MEV bots often pay higher gas to front-run transactions. It examines transaction logs for multiple transfers in the same block, which can indicate sandwich attacks. It also checks for profit extraction by comparing wallet balances before and after the transaction. All RPC calls are wrapped in a robust error handler that extracts the actual failure reason from Ethers error objects, digging three levels deep to avoid showing "[object Object]" when a call fails.

WHAT IT CANNOT SEE

This tool cannot prevent MEV attacks that occur through private mempools or Flashbots. It cannot guarantee protection against all forms of MEV. It cannot detect MEV activity that is not visible in the public mempool or on-chain. It cannot predict future MEV attacks before they happen. It cannot see transactions that are sent directly to miners through private channels. It cannot detect MEV that is executed through complex multi-transaction strategies across different blocks. It cannot guarantee that the risk assessment will hold after the transaction is submitted, since mempool conditions can change rapidly. The tool provides analysis based on current state, but it does not guarantee that a transaction will remain safe after analysis.

PLEASE NOTE

This tool supports EVM‑compatible chains only (Ethereum, Goerli, Sepolia, Arbitrum, Optimism, Polygon). Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported. The tool is read‑only and does not require signing transactions—connect is optional. No contract addresses are hardcoded; you paste the transactions and contracts you are analyzing. The tool is free and open under the BotGentz PLAYBOOK‑C specification.