Gas Estimate Overlay for Page
Free to download on every platform. Comes pre-installed on BotFone, BotPad and BotFlip — with extra free apps included.
About this app
WHAT IT DOES
The Gas Estimate Overlay for Page scans any webpage for interactive elements that trigger blockchain transactions—buttons with text like "Swap", "Mint", "Approve", "Transfer", "Send", "Buy", "Claim", "Deposit", "Withdraw", and many more. When it detects a transaction-triggering element, it uses eth_estimateGas through your connected wallet to calculate the estimated gas cost, then displays a small floating overlay badge above or near the button showing the estimated fee in both ETH (as Gwei) and USD. This gives you instant visibility into transaction costs before you click, helping you avoid surprise fees and choose the most cost-effective times to transact.
WHERE IT RUNS
It runs as a draggable overlay panel inside the BotGentz extension on any website—DeFi platforms (Uniswap, 1inch, Curve, Aave), NFT marketplaces (OpenSea, Rarible), DEX aggregators, and any other site with transaction-triggering buttons. It works by scanning the page's DOM in real time and adapting to dynamic content changes.
HOW TO USE
1. Install the free BotGentz extension and ensure you have an EVM‑compatible wallet extension installed.
2. Navigate to any page with transaction buttons.
3. Click the BotGentz icon and select "Gas Estimate Overlay for Page" from the tools menu.
4. Click "Start Scanning" to connect your wallet and begin scanning.
5. The tool automatically detects transaction buttons and overlays gas cost estimates.
6. Configure settings: choose whether to show USD values, show gas breakdown (gas limit), and adjust refresh rate.
7. Hover over or look at any transaction button to see the estimated cost.
8. The overlays update automatically as gas prices change.
9. Drag the panel to reposition it, resize it, collapse it, or press Escape to close.
THE ACTUAL MECHANISM — DOM scanning with eth_estimateGas for cost prediction
This tool uses a three‑phase approach to provide accurate gas cost overlays. First, it scans the page DOM in real time for elements that match transaction-related keywords using a combination of CSS selectors and text content analysis. The keyword list covers common transaction actions across DeFi and NFT platforms. Second, for each detected button, it builds a minimal transaction object (from address, to address set to a detected contract address if available, and empty calldata) and calls eth_estimateGas through the wallet provider to get the gas limit estimate. It then multiplies this by the current gas price (fetched via eth_gasPrice) to compute the total cost in wei, converts to ETH, and optionally to USD using a cached price feed from CoinGecko. Third, it renders a small floating badge positioned above each button using fixed positioning, styled with a dark semi‑transparent background and accent color, containing the estimated cost. The tool uses a MutationObserver to detect DOM changes, ensuring new buttons are discovered as they appear, and a configurable refresh interval to update estimates as gas prices fluctuate.
THE PANEL
The panel is fully draggable by its title bar and snaps to the nearest edge of the viewport when released. You can resize it horizontally by dragging the left or right border; the height expands to fit content up to a maximum, with scrolling inside the settings area. A collapse button minimizes the panel to a small floating chip showing "⚙️ Gas Overlay" — click it to expand back. Press Escape at any time to close the panel entirely. The panel remembers its last position, size, and expansion state per domain via localStorage.
PLEASE NOTE
- This tool requires the free BotGentz extension and a real EVM wallet extension (e.g., MetaMask) already installed in your browser.
- This tool works only on EVM‑compatible chains that support the required RPC methods.
- The tool cannot estimate gas costs for transactions that require complex calldata not visible in the DOM or that are constructed dynamically by the dApp at the time of the click. It cannot guarantee that the estimated gas cost matches the actual cost at the time of submission. It cannot determine the exact token price for USD conversion without an external price feed. It cannot detect transactions triggered via keyboard shortcuts or other non‑DOM mechanisms.
- No private keys, seed phrases, or sensitive data are ever read, stored, or transmitted. The tool only reads public network data and DOM content. Only anonymized usage metrics (panel open/close, button detections) are collected; you can disable this in the extension settings at any time.
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