Create Whale Movement Alert

WHAT IT DOES

This tool monitors your connected wallet for whale-sized transactions involving native currency (ETH/MATIC/BNB). You set a minimum value threshold — typically 100+ ETH for whale movements — and the tool polls the blockchain at your specified interval, scanning for new transactions that involve your wallet and exceed the threshold. When a whale movement is detected, the alert triggers and the transaction appears in the activity log with a whale emoji highlight. All alert configurations and activity history are stored in-memory — no data is persisted across page reloads.

HOW TO USE

Connect your MetaMask wallet using the Connect button. Give your alert a name, select what to monitor (Incoming, Outgoing, or Any transaction), set the minimum value threshold in native currency (default 100), and choose a check interval (5-300 seconds). Click "Create Whale Alert" to start monitoring. Active alerts appear in the list. When a transaction exceeding your threshold is detected, the alert status changes to "Triggered" and the transaction appears in the Whale Movements log with a 🐋 emoji and the amount highlighted. Click any transaction hash to view it on Etherscan. Use "Remove" to delete an individual alert or "Clear All" to remove all alerts and activity history.

TECHNICAL MECHANISM

The tool uses the BGWallet bridge to access the blockchain provider via ethers.js. For each active alert, it creates a JavaScript interval that runs at the user-specified frequency. On each interval tick, the tool fetches the current block number and compares it against a stored last-checked block number. It then scans for logs involving the wallet address using eth_getLogs. To handle varying RPC limits, the tool implements a chunked scanning strategy — it starts with a chunk size of 500 blocks and halves the chunk size if the RPC returns a "limit exceeded" error, continuing until the scan completes. For each transaction hash found, it fetches the full transaction and receipt, verifies the direction (incoming/outgoing), extracts the native currency value using ethers.utils.formatEther, and compares it against the configured whale threshold. Only confirmed transactions (status=1) with value exceeding the threshold are recorded. The tool deduplicates transactions using a Set of seen hashes.

WHAT IT CANNOT SEE

This tool cannot persist alerts across page reloads because it runs in an opaque-origin sandboxed frame with no storage access. It cannot send push notifications or emails without external services. It cannot detect large token transfers (ERC-20) without user-provided token addresses — only native currency transactions are monitored. It cannot detect activity that occurred before the alert was created. It cannot monitor wallets other than the currently connected wallet. It cannot detect pending or failed transactions. It cannot detect transactions sent from the wallet to itself. It cannot detect contract interaction details without ABI. It cannot detect activity on networks other than the connected network. It cannot detect transactions that were included in a block but did not emit a log event.

PLEASE NOTE

This tool works only with EVM-compatible wallets connected via the BGWallet bridge. The chunked scanning ensures compatibility with RPC providers that limit eth_getLogs ranges, but scanning large ranges may take time. Frequent polling may hit RPC rate limits on public providers. Alerts are in-memory only and will be lost when the page is refreshed or closed. The tool does not store or transmit any data — all processing occurs in your browser. This tool is provided as a lightweight whale tracking utility and should not be used as a critical financial monitoring system.