Large Transfer Alert Tool

WHAT IT DOES

Large Transfer Alert Tool is a read-only security tool that detects and alerts on ERC-20 token transfers exceeding user-defined thresholds. It scans contract logs using chunked eth_getLogs fetching (automatically halving block ranges when RPC providers reject full-range requests), decodes Transfer events to extract sender, recipient, and amount, and identifies transfers that exceed the configured threshold. The tool provides a detailed report of all large transfers sorted by amount (largest first), including sender and recipient addresses (truncated), block numbers, transaction hashes, timestamps, and gas usage, and includes an alert stub for notification integration. It helps developers and security teams monitor for suspicious large transfers, detect potential fund drains, and track high-value token movements.

HOW TO USE

Connect your EVM-compatible wallet via the BGWallet bridge and select the network where your token contract is deployed. Enter the token contract address, set the transfer threshold in token units (e.g., 10,000), and specify the block range to scan (100-10,000 blocks). Click "Monitor Large Transfers" to fetch and analyze Transfer events. Results include a summary of total large transfers found, a detailed table of each transfer with amount (highlighted in red), sender address, recipient address, block number, transaction hash, and timestamp, and an alert stub indicating which transfers would trigger notifications. The tool decodes Transfer events using the standard ERC-20 event signature and supports chunked log fetching to handle RPC provider limits. All analysis is read-only—no signatures or transactions are submitted.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to fetch contract logs via the provider. It uses the standard ERC-20 Transfer event signature (0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef) to filter logs. The tool uses chunked log fetching (fetchLogsChunked) that handles provider-specific eth_getLogs limits by recursively halving block ranges until requests succeed. For each Transfer event log, it decodes the event data: the from address is extracted from topics[1] (indexed), the to address from topics[2] (indexed), and the amount from the data field (converted from hex to decimal). The tool compares each transfer amount against the user-provided threshold and only includes transfers that exceed it. For each matching transfer, the tool retrieves the transaction details via provider.getTransaction(hash), the receipt via provider.getTransactionReceipt(hash), and the block timestamp via provider.getBlock(number). Transfers are sorted by amount in descending order, with the largest transfers displayed first. The tool is compatible with all ERC-20 tokens and supports major RPC providers.

WHAT IT CANNOT SEE

This tool has fundamental limitations that users must understand. It cannot actually send alerts or notifications—the tool provides an alert stub but requires external infrastructure for actual notifications. It cannot detect transfers that do not emit Transfer events (e.g., internal ETH transfers, transfers via proxy contracts, or non-standard implementations). It cannot determine if a large transfer is malicious or legitimate without context—the tool flags all transfers above the threshold, leaving interpretation to the user. It cannot monitor ERC-721 or other non-fungible token transfers beyond amount thresholds—only ERC-20 fungible tokens are supported. It cannot detect transfers that occur across multiple contracts or via proxy patterns—the tool only scans the specified contract address. It cannot automatically block or prevent transfers—the tool is read-only. It cannot detect transfers that occur in batches or via multi-send contracts. It cannot verify if the token has sufficient decimals or that the amount is correctly interpreted. The tool's alert stub is a placeholder for demonstration purposes.

PLEASE NOTE

This tool only supports EVM-compatible blockchains (Ethereum, Polygon, BSC, Avalanche C-Chain, Optimism, Arbitrum, and their testnets). Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported. The tool is free, open-source, requires no API keys, and uses the wallet's native provider for all read operations. For production alerting, integrate the tool's output with external notification systems.