Create Smart Contract Alert

WHAT IT DOES

This tool monitors smart contract events using eth_getLogs and alerts you when specified events are emitted. You provide the contract address, the event signature (keccak256 hash of the event), and optional filter parameters (indexed topics). The tool polls the blockchain at your specified interval, scanning for new logs that match your filter, and triggers an alert when events are detected. All alert configurations 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, enter the contract address to monitor, the event signature (topic hash), and optionally a filter topic (e.g., a specific address to filter Transfer events). Use the preset buttons (Transfer, Approval, Deposit) to quickly add common event signatures. Choose a check interval (5-300 seconds). Click "Create Alert" to start monitoring. Active alerts appear in the list. When an event is detected, the alert status changes to "Triggered" and the event appears in the Events Detected log with the transaction hash and contract address. Click any transaction hash to view it on the block explorer. Use "Remove" to delete an individual alert or "Clear All" to remove all alerts and 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, it fetches the current block number and compares it against a stored last-checked block number. It then builds an eth_getLogs filter with the contract address, event signature, and optional topic filters. To handle varying RPC eth_getLogs 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 log found, it deduplicates using the transaction hash and log index, records the event, and triggers the alert. The tool tracks seen events to avoid duplicate notifications.

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 events that occurred before the alert was created. It cannot monitor contracts other than those specified. It cannot detect pending or failed transactions — only confirmed transactions in blocks. It cannot decode complex event data without the full contract ABI — it only detects the presence of events. It cannot detect events on networks other than the connected network. It cannot detect events that do not match the specified filter parameters. It cannot detect events if the contract does not emit the specified event signature. It cannot detect internal contract calls or events from proxy contracts without the proxy's address.

PLEASE NOTE

This tool works only with EVM-compatible wallets connected via the BGWallet bridge. The event signature must be the keccak256 hash of the event signature string (e.g., "Transfer(address,address,uint256)"). You can compute this hash using online tools or ethers.js utils. 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 event monitoring utility and should not be used as a critical security alerting system.