# Monitor product prices on any online store

**Use case:** 

Watch two product pages (books.toscrape.com) with a CSS selector on the product box, and get an alert when the price moves or the item goes out of stock. Rows carry numericChanges with the old and new price. Replace the URLs and selector with your own store, run once to save prices, then schedule it daily. $0.002 per page check.

## Input

```json
{
  "urlList": [
    "https://www.python.org/downloads/",
    "https://news.ycombinator.com"
  ],
  "urls": [
    {
      "url": "https://books.toscrape.com/catalogue/a-light-in-the-attic_1000/index.html",
      "userData": {
        "selector": ".product_main",
        "name": "A Light in the Attic"
      }
    },
    {
      "url": "https://books.toscrape.com/catalogue/tipping-the-velvet_999/index.html",
      "userData": {
        "selector": ".product_main",
        "name": "Tipping the Velvet"
      }
    }
  ],
  "monitorName": "book-prices",
  "watchProduct": false,
  "priceDropPercent": 0,
  "ignorePatterns": [
    "(d+ available)"
  ],
  "outputOnlyChanges": false,
  "mode": "auto",
  "maxConcurrency": 5,
  "alertOnRemoved": true,
  "alertOnError": false,
  "errorThreshold": 3,
  "screenshotOnChange": false,
  "dryRunNotifications": false,
  "watchKeywords": [
    "£",
    "out of stock"
  ],
  "minChangedLines": 0,
  "ignoreCommonNoise": false,
  "wholePageFallback": false,
  "aiSummary": false,
  "baselineMode": "rolling",
  "resetBaseline": false,
  "httpVia": "auto"
}
```

## Output

```json
{
  "name": {
    "label": "Name",
    "format": "text"
  },
  "url": {
    "label": "URL",
    "format": "link"
  },
  "status": {
    "label": "Status",
    "format": "text"
  },
  "significant": {
    "label": "Significant",
    "format": "boolean"
  },
  "addedCount": {
    "label": "Lines added",
    "format": "number"
  },
  "removedCount": {
    "label": "Lines removed",
    "format": "number"
  },
  "aiSummary": {
    "label": "AI summary",
    "format": "text"
  },
  "screenshotUrl": {
    "label": "Screenshot",
    "format": "image"
  },
  "checkedAt": {
    "label": "Checked at",
    "format": "date"
  },
  "error": {
    "label": "Error",
    "format": "text"
  }
}
```

## How it works

### 1. Sign up on Apify or log in

The Website Change Monitor - Page Change Detection & Alerts Actor is ready to run with the inputs already set for "Monitor product prices on any online store". [Sign up or log in](https://console.apify.com/create-task-from-example/L7sZNMJwpaGtSWOag) and you'll land in Apify Console with a copy of this exact task.

### 2. Start the "Monitor product prices on any online store" task

The Website Change Monitor - Page Change Detection & Alerts Actor will start running based on the input automatically. You can also change all the input fields, like pages to watch, pages with per-page settings (optional), and more, to match your specific use case.

### 3. Receive the "Monitor product prices on any online store" output

Monitor the progress in real time. You will be notified as soon as your dataset is complete and ready for review. Each result includes data such as name, URL, status, and more.

### 4. Integrate into your workflow

The final output is delivered in JSON, CSV, or Excel format, ready to be plugged into your workflow. You can also [run the "Monitor product prices on any online store" task via API](https://apify.com/tidytools/website-change-monitor.md).

## About this Actor

This example demonstrates how to use [Website Change Monitor - Page Change Detection & Alerts](https://apify.com/tidytools/website-change-monitor.md) with a specific input configuration. Visit the [Actor detail page](https://apify.com/tidytools/website-change-monitor.md) to learn more, explore other use cases, and run it yourself.


## How to integrate an Actor?

This Task's input is already configured above. Use it as-is rather than inventing a new one.

Do not guess an integration path. Every one of them is in the agent quickstart at https://apify.com/agents.md: the Apify MCP server, Agent Skills with the Apify CLI, the JavaScript and Python clients, the REST API, and the account-free path for an agent with no human to sign in. It also carries the rule on stating cost before the first paid run.

For full API examples (JavaScript, Python, CLI, MCP, OpenAPI), see this Task's Actor page: https://apify.com/tidytools/website-change-monitor.md

Each client library has reference documentation the quickstart does not restate: [JavaScript/TypeScript](https://docs.apify.com/api/client/js/docs.md) (`npm install apify-client`) and [Python](https://docs.apify.com/api/client/python/docs.md) (`pip install apify-client`).