NFT Listing Price Alert

WHAT IT DOES

NFT Listing Price Alert watches the current page for NFT listing prices, monitors floor price changes and specific NFT price movements, then triggers visual and desktop notifications when prices cross user-defined thresholds, with optional sound alerts. The tool helps you stay informed about price movements without constantly refreshing marketplace pages, enabling timely buy or sell decisions.

WHERE IT RUNS

This tool works on any webpage that displays NFT listing prices, including NFT marketplaces, collection pages, and auction sites. It automatically detects prices from page content using multiple detection strategies. The script runs on all websites as designated in its match patterns.

HOW TO USE

After installing the BotGentz extension, navigate to any NFT listing or collection page. Click the NFT Listing Price Alert icon in your browser toolbar or use the keyboard shortcut (Alt+L). The panel will open. Click "Connect Wallet" to connect your real EVM wallet extension—this provides network context and enables optional balance-based alerts. Configure your price threshold in ETH, choose the alert condition (Below Threshold, Above Threshold, or Equal to Threshold), and set the check interval in seconds. Optionally, enter a specific NFT ID to monitor a single NFT rather than the floor price. Toggle desktop notifications and sound alerts on or off. Click "Start Monitoring" to begin automated price checks. The panel displays the current detected price and the last alert. Click "Check Price Now" for an immediate check. Use "Stop Monitoring" to pause alerts or "Reset Alert" to clear the triggered state.

TECHNICAL SECTION — DOM-BASED PRICE DETECTION AND THRESHOLD TRIGGERING

Unlike API-based price trackers that require marketplace API access, this tool uses a DOM-based price detection engine that works directly with the page content displayed in your browser. It scans the page text using multiple regex patterns to identify Ethereum-denominated prices, then filters and sorts detected values to find the floor price. For specific NFT monitoring, it uses pattern matching to find prices associated with a given NFT ID. The engine then compares detected prices against your configured threshold using the selected condition (below, above, or equal). When a price crosses the threshold, the tool triggers a multi-channel alert: a panel flash message, a desktop notification via GM_notification, and an optional sound alert using the Web Audio API. The engine maintains state to prevent repeated alerts on the same price movement, resetting only when the price moves away from the threshold and crosses it again. This approach provides reliable alerts without requiring API keys or external data sources.

THE PANEL

The panel is draggable anywhere on the screen and remembers its position per site. It can snap to the left, right, top, or bottom edges, or float freely. Collapse it to a small status indicator when you need more page visibility, and expand it again with a single click. Resize it vertically or horizontally to show more details. Press Escape to close the panel instantly. All settings (price threshold, alert condition, check interval, specific NFT ID, desktop notifications, sound alerts) are saved globally and persist across sessions.

PLEASE NOTE

This tool requires the free BotGentz extension and a real EVM wallet extension already installed in your browser. EVM chains only—supports Ethereum Mainnet, Polygon, Arbitrum, and Optimism. Wallet connection is read-only; this tool never initiates transactions or signs messages. Cannot access real-time price data from off-platform sources or private marketplaces, cannot detect price changes that occur between page refresh intervals, cannot read listing prices for NFTs that are not visible on the current page view, and cannot trigger alerts if the page content structure changes and prevents price detection. Always verify price information manually before making any trading decisions. Websites change their layouts frequently; scripts may need updates, and we work to keep them current but cannot guarantee uninterrupted operation.