Kayak Price Alert History Badge

WHAT IT DOES

This userscript adds price trend visibility to your Kayak price alerts dashboard. It reads alert data from the page—including destination, current price, previous price, and price history—and calculates the price change trend and percentage change for each alert. A color-coded badge appears on every alert: green for price dropped, yellow for stable, and red for price increased. Each badge shows the trend direction, percentage change, and current price. A price history timeline displays the sequence of prices for each alert. A summary panel shows total alerts, average price change, counts of dropped/increased/stable alerts, and the best deal alert (largest price drop). A one-click button opens the full price history. This is invaluable for travelers, frequent flyers, and deal hunters who need to monitor flight prices, identify the best time to book, and catch price drops on their desired routes.

WHERE IT RUNS

The script runs on all Kayak web application pages at *.kayak.com/*, with automatic detection of price alerts pages, flight search results, and any page displaying price information. It works across all Kayak interfaces by using multiple selector strategies to find alert items, destinations, prices, and price history data. The script detects dynamic content loading and re-applies price alert badges when the alerts list updates. It runs across the entire Kayak domain, ensuring coverage whether you're viewing your price alerts dashboard, a specific flight search, or a price history page.

HOW TO USE

Install the script via the BotGentz extension and navigate to your Kayak price alerts page or flight search results. Price alert badges will appear automatically on every alert. Each badge shows the trend direction, percentage change, and current price with a color-coded background. The price history timeline shows the sequence of prices for each alert. The summary panel shows total alerts, average price change, counts of dropped, increased, and stable alerts, and the best deal alert. Click the ↗ button next to any alert to open its full price history in a new tab. Use the panel controls to customize your experience: toggle price alert badges on or off, show or hide trend indicators, enable or disable price change percentages, show or hide the summary panel, or toggle the price history timeline. The "Refresh" button manually rescans the page for updated alert data, and the "Copy summary" button exports the alert summary to your clipboard.

THE MECHANISM - ALERT EXTRACTION, TREND CALCULATION, AND PRICE HISTORY ANALYSIS

This script identifies alert data by scanning each alert item using a cascading selector strategy. It extracts destinations from destination elements, current prices from price elements, and price history from price history entries or by parsing price patterns from text. The price change is calculated by comparing the current price to the previous price (from history or previous price elements). The percentage change is calculated as (current - previous) / previous × 100. The trend is determined by the sign of the change: negative is "down," positive is "up," and zero is "stable." The price history timeline extracts all price points from the history and displays them as a sequence. The badge is created as a DOM element with inline styles and inserted into the destination cell. The summary panel aggregates data and identifies the best deal (largest price drop).

THE PANEL

The control panel appears as a floating, draggable element that you can position anywhere on the Kayak page. Drag by the header to reposition it, and the position is saved per site using GM_setValue so it stays where you left it across sessions. Release the panel near any edge and it snaps into place, keeping your workspace organized. Click the panel header to collapse it into a small bubble showing only the chart emoji (📊), minimizing distraction while keeping controls accessible. Drag from the bubble to restore the full panel. The panel automatically resizes to fit its content and includes all setting toggles, action buttons, and a price trend legend. Press the Escape key to quickly collapse the panel to its minimized state. The panel remains visible across page navigation within Kayak, with price alert badges updating automatically as you move between views.

PLEASE NOTE

This script requires the free BotGentz extension to function. It is designed for Kayak users who need to monitor flight prices and catch the best deals. The script reads only visible alert data from the DOM—it does not access Kayak's API, your account credentials, or any sensitive information. All settings (badge visibility, trend toggle, change pct toggle, summary toggle, timeline toggle, and panel position) are stored locally using GM_setValue and never leave your browser. The script does not modify your Kayak data—it only reads and visualizes visible price alert information. Price change calculations depend on the availability of previous price data; if previous price is not available, the alert will show as "stable" with no percentage change. If Kayak updates its website structure, the script may need to be updated to match new selectors. The price history timeline shows prices as they appear on the page; if the page only shows the latest price, the timeline may be limited.