Large Transaction Alert

WHAT IT DOES

Large Transaction Alert watches the current page for large transactions on the blockchain, reads transaction data from recent blocks via eth_getBlockByNumber and eth_getTransactionByHash, and triggers alerts when a transaction exceeds a user-defined value threshold (in ETH or token value), with filters for specific senders, receivers, or token addresses. It helps you track whale activity, monitor significant fund movements, and stay informed about large transfers.

WHERE IT RUNS

This tool operates as a userscript within the BotGentz extension framework, running directly in your browser on any website. It works on any EVM-compatible blockchain page—Ethereum, Polygon, Arbitrum, Optimism, and more—where block data is accessible. The tool integrates seamlessly into your workflow, appearing as a draggable panel that stays accessible as you monitor blockchain activity.

HOW TO USE

Set the minimum transaction value threshold in ETH in the "Transaction Settings" section. Optionally, add filters for specific sender addresses, receiver addresses, or token addresses to narrow your monitoring. Set the refresh interval and toggle desktop notifications on or off. Click "Start Transaction Monitoring" to connect your real wallet extension, which will begin scanning recent blocks for large transactions at your specified interval. The panel displays a list of detected large transactions with their value, sender, receiver, and block number. Use "Check Now" for an immediate scan, "Clear Transaction History" to reset the list, or "Stop Monitoring" to disconnect.

TECHNICAL OPERATION

Large Transaction Alert uses raw JSON-RPC calls via window.ethereum.request() to interact with the blockchain—no external library required for basic operations. It loads ethers at runtime using a simple script tag injection for ABI encoding and contract interactions. The tool gets the current block number and retrieves all transactions from recent blocks using eth_getBlockWithTransactions. It checks each transaction's value (in ETH) against the user-defined threshold, applies any sender/receiver/token filters, and triggers alerts when a match is found. For token transfers, the tool can detect interactions with token contracts via the to address or input data. The tool stores a history of detected transactions in GM_setValue, maintaining up to 50 entries for reference. Each alert includes the transaction hash, value, sender, receiver, and block number.

THE PANEL

The Large Transaction Alert panel is fully draggable and remembers its position between sessions using GM_setValue. It snaps to the edge of the viewport for a clean interface and can be collapsed to a small icon when not in use. The panel is resizable to accommodate longer content. Press Escape to quickly close or collapse the panel. The design is optimized for productivity with a dark theme, clear visual hierarchy, and responsive controls that adapt to your workflow.

PLEASE NOTE

This tool requires the free BotGentz extension installed in your browser and a real EVM wallet extension (MetaMask, Rabby, etc.) already installed. EVM chains only—this does not work on non-EVM blockchains. The tool cannot detect transactions that are not yet confirmed, cannot detect off-chain transactions, cannot detect private mempool transactions, cannot read transaction details if the block is not available, and cannot determine token transfer values if the token contract does not expose the required view functions. No private keys are stored or transmitted—all data is read-only from the blockchain. Always verify the threshold and filters before starting monitoring.