AutoTrader Web Price Drop Alert

WHAT IT DOES

AutoTrader Web Price Drop Alert reads the vehicle price from AutoTrader listing pages and displays a price drop alert badge whenever the price decreases. The badge shows the amount and percentage of the drop, color-coded green for drops and neutral for no change. The extension tracks price history for each vehicle, storing up to 20 price records with timestamps. A price history chart is displayed in the panel, showing the price progression over time. When a price drop exceeds your configured threshold percentage, a desktop notification is triggered. The panel shows the current price, price drop alert, and a full price history list with dates and prices. A "Clear History" button lets you remove price history for the current vehicle.

WHERE IT RUNS

This extension works on all AutoTrader pages at autotrader.com and its subdomains, specifically on vehicle listing and detail pages. It runs on the main vehicle view, the search results page, and any page displaying vehicle pricing information. The extension operates entirely within your browser and does not access AutoTrader's servers directly—it reads only what is visible on the page you are viewing. It works alongside the free BotGentz extension, which provides the necessary scripting environment.

HOW TO USE

Install the extension, then navigate to autotrader.com and open any vehicle listing. The extension automatically reads the vehicle price and displays it in the panel. Click the extension's icon in your browser toolbar to open the panel. The panel shows the vehicle name, current price, and a price history list. If a price drop is detected, an alert banner appears with the drop amount and percentage. Use the "Refresh" button to manually update the panel with the latest price. The alert threshold setting controls what percentage drop triggers a notification—choose from 1%, 2%, 3%, 5%, or 10%. The "Show alert badge" toggle controls whether price drop badges appear. Use the "Clear History" button to remove price history for the current vehicle.

PER-VEHICLE PRICE HISTORY WITH DEDUPLICATION AND COMPARISON

Unlike simple price scrapers, this extension maintains a persistent price history per vehicle using a unique identifier derived from the vehicle's VIN or listing name. Each time you visit a listing, the current price is compared to the last recorded price. If the price is different and not a duplicate, a new record is added with a timestamp. The extension then compares the last two price records to detect drops, calculating both the absolute amount and percentage change. The threshold system compares the percentage drop against the user-configured value and triggers a desktop notification when exceeded. Price history is kept to a maximum of 20 records per vehicle to manage storage, with the oldest records being removed automatically. This approach provides reliable price tracking across multiple visits without manual data entry.

THE PANEL

The panel supports drag-to-move anywhere on the page. It remembers its position per site, so it stays where you placed it on autotrader.com. Click the panel header to collapse it down to just the minimized bubble, or click the expand handle to show the full panel. The panel can be resized by dragging the bottom-right corner. Press the Escape key to close the expanded panel and return to the minimized state. All panel settings, including position, size, collapsed state, alert threshold, badge visibility, and price history, are saved per site and persist across browsing sessions.

PLEASE NOTE

This extension requires the free BotGentz extension to be installed and active, as it provides the underlying DOM injection and script execution environment. AutoTrader's website changes periodically, and vehicle element structures, class names, and page layouts may be updated. When that happens, the extension may stop detecting prices until an update is released. The extension stores your alert threshold, badge visibility, and price history locally in your browser's storage using GM_setValue. Price history is stored as a key-value object where keys are vehicle identifiers and values are arrays of price records with timestamps. Price drop notifications are limited to once per day per vehicle to prevent notification fatigue. No data is ever sent to any server, and no personal information is collected. You can clear all stored settings and price history at any time using the "Clear History" button or by clearing your browser data for autotrader.com.