Competitor Monitor - Website Change Detection & Price Tracker

🎯 Monitor competitor websites for changes, track prices, detect stock availability, and stay ahead of the competition.

🚀 Overview

Competitor Monitor is a powerful Apify Actor that automatically monitors competitor websites for changes. Built with PlaywrightCrawler for robust, anti-detection web scraping, it tracks content modifications, price changes, and stock availability across multiple pages.

Perfect for e-commerce businesses, market researchers, and anyone who needs to stay informed about competitor activities.

✨ Features

📊 Monitoring Modes

• Full Page Monitor - Track any changes across entire web pages
• CSS Selector Monitor - Extract and monitor specific elements using CSS selectors
• Price Tracker - Dedicated price monitoring with smart parsing (US & EU formats)
• Stock Monitor - Detect out-of-stock and back-in-stock events

💰 Price Tracking

• Smart Price Parser - Handles $1,299.99 (US) and 1.299,99 € (EU) formats
• Price Drop Alerts - Get notified when prices decrease
• Threshold Control - Only alert on significant price drops (configurable %)
• Price History - Complete price history stored in dataset

📦 Stock Monitoring

• Out of Stock Detection - Detect "out of stock", "unavailable", "rupture de stock"
• Back in Stock Alerts - Know when items become available again
• Multi-language Support - Works with English, French, and other languages

🔍 Change Detection

• SHA-256 Hashing - Reliable content comparison using cryptographic hashes
• Diff Generation - See exactly what changed between runs
• Historical Data - All snapshots stored in Apify dataset

🛡️ Anti-Detection

• Random User Agents - Rotates through 7+ realistic browser fingerprints
• Smart Delays - 2-5 second random delays between requests
• Proxy Support - Works with Apify Proxy or custom proxy configurations
• Concurrent Browsers - Up to 5 concurrent browser instances (configurable)

📦 Installation

# Install dependencies
npm install

# Run tests
npm test

# Start the Actor locally
npm start

🎯 Usage

Basic Monitoring

{
  "urls": [
    { "url": "https://competitor1.com/product" },
    { "url": "https://competitor2.com/pricing" }
  ],
  "mode": "selector",
  "selectors": [".product-title", ".price", ".description"]
}

Price Tracking

{
  "urls": [
    { "url": "https://competitor.com/product/123" },
    { "url": "https://competitor.com/product/456" }
  ],
  "mode": "price",
  "priceSelector": ".product-price",
  "notifyPriceDrop": true,
  "priceDropThreshold": 10
}

Stock Monitoring

{
  "urls": [
    { "url": "https://store.com/product/sku-123" }
  ],
  "mode": "stock",
  "stockSelector": ".availability",
  "outOfStockKeywords": ["out of stock", "sold out", "unavailable"],
  "inStockKeywords": ["in stock", "add to cart", "buy now"]
}

Multi-Page Monitoring with Schedule

{
  "urls": [
    { "url": "https://competitor.com/products" },
    { "url": "https://competitor.com/pricing" },
    { "url": "https://competitor.com/about" }
  ],
  "mode": "selector",
  "selectors": ["h1", ".content", ".pricing-table"],
  "maxConcurrency": 3,
  "proxyConfiguration": { "useApifyProxy": true }
}

📋 Input Schema

Parameter	Type	Default	Description
urls	array	required	List of URLs to monitor
mode	string	selector	Monitor mode: full-page, selector, price, stock
selectors	array	["body"]	CSS selectors to extract (for selector mode)
priceSelector	string	.price	CSS selector for price element
stockSelector	string	.stock-status	CSS selector for stock status
notifyOnChange	boolean	true	Trigger on any content change
notifyPriceDrop	boolean	true	Trigger on price decrease
priceDropThreshold	number	0	Minimum % drop to trigger alert
notifyOutOfStock	boolean	true	Trigger when item goes out of stock
notifyBackInStock	boolean	true	Trigger when item comes back in stock
maxConcurrency	number	5	Max concurrent browser pages
proxyConfiguration	object	{}	Proxy settings

📤 Output

Each scrape produces a dataset record with:

{
  "url": "https://competitor.com/product",
  "title": "Product Page",
  "contentHash": "abc123...",
  "content": "Extracted content...",
  "price": 49.99,
  "currency": "USD",
  "inStock": true,
  "changed": true,
  "changeType": "price-drop",
  "previousHash": "def456...",
  "previousPrice": 59.99,
  "priceChangePercent": -16.67,
  "diff": "1 changed",
  "timestamp": "2024-01-15T10:30:00.000Z",
  "mode": "price",
  "triggered": true
}

🔄 Scheduling

For continuous monitoring, schedule the Actor to run automatically:

1. Go to the Actor page on Apify Console
2. Click "Schedule"
3. Set frequency (e.g., every 6 hours, daily)
4. Configure input for your monitoring needs

The Actor maintains state between runs using Apify's Key-Value Store, so each run compares against the previous state.

🛠️ Technical Details

• Crawler: PlaywrightCrawler (headless Chromium)
• Anti-Detection: Random user agents, smart delays, proxy support
• Storage: Apify Dataset (results) + Key-Value Store (state)
• Concurrency: Configurable up to 20 browsers (default 5)
• Timeout: 60 seconds per page

📝 Examples

Monitor Product Prices Across Competitors

{
  "urls": [
    { "url": "https://amazon.com/dp/B09V3KXJPB" },
    { "url": "https://bestbuy.com/site/product/12345678" },
    { "url": "https://walmart.com/ip/123456789" }
  ],
  "mode": "price",
  "priceSelector": "#priceblock_ourprice, .a-price-whole",
  "notifyPriceDrop": true,
  "priceDropThreshold": 5
}

Monitor Competitor Feature Pages

{
  "urls": [
    { "url": "https://competitor.com/features" }
  ],
  "mode": "selector",
  "selectors": [
    ".feature-list",
    ".pricing-tier",
    ".testimonial"
  ]
}

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

💰 Pricing

Pay-per-use, no monthly fees:

	Price
Actor start	$0.01
Per result	$0.01

💡 Example: A run returning 500 results costs $5.01 total ($0.01 start + 500 × $0.01).

📄 License

This project is licensed under the Apache 2.0 License - see the LICENSE file for details.

🔗 Related Actors

• Website Content Crawler - General purpose web scraping
• SEO Audit - SEO analysis tools
• Price Tracker - Specialized price monitoring

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Keywords: website monitor, price tracker, competitor analysis, stock monitor, change detection, web scraping, automation, e-commerce monitoring, price drop alerts, stock availability, web change detection, competitor tracking, market monitoring, price comparison, product monitoring

Tags: monitoring price-tracking competitor-analysis web-scraping automation e-commerce stock-monitoring change-detection