# WatchTower – Website Change & Price Monitor (`hichemdev/watchtower-website-change-monitor`) Actor

Monitor any website for changes - track competitor prices, stock/availability, and content updates with field-level precision. Get instant webhook alerts on any change, a price increase or drop, or when a keyword appears. Ideal for price monitoring, competitor intelligence, and compliance.

- **URL**: https://apify.com/hichemdev/watchtower-website-change-monitor.md
- **Developed by:** [Hichem Ben Moussa](https://apify.com/hichemdev) (community)
- **Categories:** Business, E-commerce, Automation
- **Stats:** 2 total users, 1 monthly users, 100.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

from $2.00 / 1,000 results

This Actor is paid per event and usage. You are charged both the fixed price for specific events and for Apify platform usage.

Learn more: https://docs.apify.com/platform/actors/running/actors-in-store#pay-per-event

## What's an Apify Actor?

Actors are a software tools running on the Apify platform, for all kinds of web data extraction and automation use cases.
In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours,
and optionally produces a well-defined JSON output, datasets with results, or files in key-value store.
In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server.
Actors are written with capital "A".

## How to integrate an Actor?

If asked about integration, you help developers integrate Actors into their projects.
You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready.
The best way to integrate Actors is as follows.

In JavaScript/TypeScript projects, use official [JavaScript/TypeScript client](https://docs.apify.com/api/client/js.md):

```bash
npm install apify-client
```

In Python projects, use official [Python client library](https://docs.apify.com/api/client/python.md):

```bash
pip install apify-client
```

In shell scripts, use [Apify CLI](https://docs.apify.com/cli/docs.md):

````bash
# MacOS / Linux
curl -fsSL https://apify.com/install-cli.sh | bash
# Windows
irm https://apify.com/install-cli.ps1 | iex
```bash

In AI frameworks, you might use the [Apify MCP server](https://docs.apify.com/platform/integrations/mcp.md).

If your project is in a different language, use the [REST API](https://docs.apify.com/api/v2.md).

For usage examples, see the [API](#api) section below.

For more details, see Apify documentation as [Markdown index](https://docs.apify.com/llms.txt) and [Markdown full-text](https://docs.apify.com/llms-full.txt).


# README

## WatchTower – Website Change & Price Monitor 🔔

**Monitor any website for changes — automatically.** WatchTower watches a list of URLs and tells you the moment a **price**, **stock status**, **headline**, **policy**, or any on-page value changes. It tracks *specific fields* (not noisy full-page HTML), so you only get alerts that matter — and it sends them straight to your **webhook, Slack, Zapier, or Make**.

Perfect for **competitor price monitoring**, **stock/availability tracking**, **content change detection**, and **compliance monitoring**.

### ✨ Features

- **Field-level monitoring** — target one element with a CSS selector (e.g. `.price`) or watch the whole page.
- **Smart triggers** — alert on *any* change, only on a price **increase**, a price **decrease**, or when a **keyword appears** (e.g. "in stock").
- **Numeric awareness** — parse prices/quantities and report the exact delta (e.g. `-$30.00`).
- **Change history** — every run stores a baseline, then reports only what's new.
- **Webhook alerts** — POST every change to Slack, Zapier, Make, or your own API.
- **Runs on a schedule** — set it to run hourly/daily and it becomes a hands-off monitor.
- **No proxy required** for most sites — cheap to run.

### 🎯 Use cases

- **E-commerce sellers** — track competitor prices and get alerted on drops before you lose the sale.
- **Deal & coupon sites** — detect price drops and back-in-stock events automatically.
- **Brands & MAP compliance** — watch reseller pages for policy-breaking prices.
- **Procurement / revenue teams** — monitor supplier and competitor pricing.
- **SEO & marketing** — get notified when a competitor changes a title, CTA, or landing-page copy.
- **Compliance & legal** — track changes to terms, policies, or regulatory pages.

### 📥 Input

| Field | Type | Description |
|---|---|---|
| `watches` | array | One entry per thing to monitor (see below). **Required.** |
| `onlyReportChanges` | boolean | Only output rows where something changed. Default `true`. |
| `webhookUrl` | string | Optional. Receives a JSON POST for every change. |
| `proxyConfiguration` | object | Optional. Off by default. |

Each **watch** entry:

```json
{
  "url": "https://shop.com/product/123",
  "selector": ".price-now",
  "label": "Competitor price",
  "extract": "number",
  "notifyOn": "decrease",
  "keyword": "in stock"
}
````

- `url` *(required)* — page to check.
- `selector` — CSS selector for one element. Omit to watch the whole page text.
- `label` — friendly name shown in output/alerts.
- `extract` — `text` (default), `number` (parses a price/quantity), or `html`.
- `notifyOn` — `change` (default), `increase`, `decrease`, or `contains`.
- `keyword` — required when `notifyOn` is `contains`.

### 📤 Output

```json
{
  "watchId": "a1b2c3d4e5f6a7b8",
  "label": "Competitor price",
  "url": "https://shop.com/product/123",
  "selector": ".price-now",
  "extract": "number",
  "previousValue": 129.0,
  "currentValue": 99.0,
  "changed": true,
  "changeType": "decrease",
  "numericDelta": -30.0,
  "isFirstRun": false,
  "checkedAt": "2026-07-14T09:00:00.000Z"
}
```

### 🔌 Integrations & scheduling

- **Schedule** it in Apify (hourly/daily) so monitoring runs automatically.
- Set `webhookUrl` to a **Slack** incoming webhook, a **Zapier**/**Make** catch-hook, or your own endpoint to get instant alerts.
- Export results to **CSV, Excel, JSON, or Google Sheets** from the dataset, or pull them via the Apify API.

### ❓ FAQ

**Does it work on JavaScript-heavy pages?** v1 fetches static HTML, which covers most price/stock/content pages. JavaScript rendering is on the roadmap.

**Do I need a proxy?** No — most public pages work without one. A proxy is optional for sites that block plain requests.

**How is it priced?** Pay per result — you're charged per URL checked. No subscription. Run it as often as you like and only pay for the checks you use.

**Can it monitor multiple pages at once?** Yes — add as many `watches` entries as you need in a single run.

### 🗺️ Roadmap

- JavaScript rendering for dynamic / SPA pages
- Visual / screenshot diffing
- Multiple fields per URL
- AI "summarize what changed"
- Built-in email digests

# Actor input Schema

## `watches` (type: `array`):

One entry per thing you want to watch. Each entry supports:
• url (required)
• selector – CSS selector to watch just one element (e.g. ".price"). Omit to watch the whole page's text.
• label – a friendly name for this watch.
• extract – "text" (default), "number" (parses a price/quantity), or "html".
• notifyOn – "change" (default), "increase", "decrease", or "contains".
• keyword – required when notifyOn is "contains" (e.g. "in stock").

## `onlyReportChanges` (type: `boolean`):

Recommended ON for alerting. On the very first run each watch is stored as a baseline and always shown so you can confirm the starting values.

## `webhookUrl` (type: `string`):

If set, WatchTower sends a JSON POST here for every detected change. Works with Slack, Zapier, Make, or your own endpoint.

## `proxyConfiguration` (type: `object`):

Optional. Most public pages need no proxy. Datacenter proxy is included in your Apify plan if a site blocks plain requests.

## Actor input object example

```json
{
  "watches": [
    {
      "url": "https://example.com",
      "label": "Example homepage headline",
      "selector": "h1",
      "extract": "text",
      "notifyOn": "change"
    }
  ],
  "onlyReportChanges": true,
  "proxyConfiguration": {
    "useApifyProxy": false
  }
}
```

# API

You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup.

## JavaScript example

```javascript
import { ApifyClient } from 'apify-client';

// Initialize the ApifyClient with your Apify API token
// Replace the '<YOUR_API_TOKEN>' with your token
const client = new ApifyClient({
    token: '<YOUR_API_TOKEN>',
});

// Prepare Actor input
const input = {
    "watches": [
        {
            "url": "https://example.com",
            "label": "Example homepage headline",
            "selector": "h1",
            "extract": "text",
            "notifyOn": "change"
        }
    ]
};

// Run the Actor and wait for it to finish
const run = await client.actor("hichemdev/watchtower-website-change-monitor").call(input);

// Fetch and print Actor results from the run's dataset (if any)
console.log('Results from dataset');
console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`);
const { items } = await client.dataset(run.defaultDatasetId).listItems();
items.forEach((item) => {
    console.dir(item);
});

// 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs

```

## Python example

```python
from apify_client import ApifyClient

# Initialize the ApifyClient with your Apify API token
# Replace '<YOUR_API_TOKEN>' with your token.
client = ApifyClient("<YOUR_API_TOKEN>")

# Prepare the Actor input
run_input = { "watches": [{
            "url": "https://example.com",
            "label": "Example homepage headline",
            "selector": "h1",
            "extract": "text",
            "notifyOn": "change",
        }] }

# Run the Actor and wait for it to finish
run = client.actor("hichemdev/watchtower-website-change-monitor").call(run_input=run_input)

# Fetch and print Actor results from the run's dataset (if there are any)
print("💾 Check your data here: https://console.apify.com/storage/datasets/" + run["defaultDatasetId"])
for item in client.dataset(run["defaultDatasetId"]).iterate_items():
    print(item)

# 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start

```

## CLI example

```bash
echo '{
  "watches": [
    {
      "url": "https://example.com",
      "label": "Example homepage headline",
      "selector": "h1",
      "extract": "text",
      "notifyOn": "change"
    }
  ]
}' |
apify call hichemdev/watchtower-website-change-monitor --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "command": "npx",
            "args": [
                "mcp-remote",
                "https://mcp.apify.com/?tools=hichemdev/watchtower-website-change-monitor",
                "--header",
                "Authorization: Bearer <YOUR_API_TOKEN>"
            ]
        }
    }
}

```

## OpenAPI specification

```json
{
    "openapi": "3.0.1",
    "info": {
        "title": "WatchTower – Website Change & Price Monitor",
        "description": "Monitor any website for changes - track competitor prices, stock/availability, and content updates with field-level precision. Get instant webhook alerts on any change, a price increase or drop, or when a keyword appears. Ideal for price monitoring, competitor intelligence, and compliance.",
        "version": "0.1",
        "x-build-id": "PlgzRc2bCDd5bxCcT"
    },
    "servers": [
        {
            "url": "https://api.apify.com/v2"
        }
    ],
    "paths": {
        "/acts/hichemdev~watchtower-website-change-monitor/run-sync-get-dataset-items": {
            "post": {
                "operationId": "run-sync-get-dataset-items-hichemdev-watchtower-website-change-monitor",
                "x-openai-isConsequential": false,
                "summary": "Executes an Actor, waits for its completion, and returns Actor's dataset items in response.",
                "tags": [
                    "Run Actor"
                ],
                "requestBody": {
                    "required": true,
                    "content": {
                        "application/json": {
                            "schema": {
                                "$ref": "#/components/schemas/inputSchema"
                            }
                        }
                    }
                },
                "parameters": [
                    {
                        "name": "token",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "string"
                        },
                        "description": "Enter your Apify token here"
                    }
                ],
                "responses": {
                    "200": {
                        "description": "OK"
                    }
                }
            }
        },
        "/acts/hichemdev~watchtower-website-change-monitor/runs": {
            "post": {
                "operationId": "runs-sync-hichemdev-watchtower-website-change-monitor",
                "x-openai-isConsequential": false,
                "summary": "Executes an Actor and returns information about the initiated run in response.",
                "tags": [
                    "Run Actor"
                ],
                "requestBody": {
                    "required": true,
                    "content": {
                        "application/json": {
                            "schema": {
                                "$ref": "#/components/schemas/inputSchema"
                            }
                        }
                    }
                },
                "parameters": [
                    {
                        "name": "token",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "string"
                        },
                        "description": "Enter your Apify token here"
                    }
                ],
                "responses": {
                    "200": {
                        "description": "OK",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "$ref": "#/components/schemas/runsResponseSchema"
                                }
                            }
                        }
                    }
                }
            }
        },
        "/acts/hichemdev~watchtower-website-change-monitor/run-sync": {
            "post": {
                "operationId": "run-sync-hichemdev-watchtower-website-change-monitor",
                "x-openai-isConsequential": false,
                "summary": "Executes an Actor, waits for completion, and returns the OUTPUT from Key-value store in response.",
                "tags": [
                    "Run Actor"
                ],
                "requestBody": {
                    "required": true,
                    "content": {
                        "application/json": {
                            "schema": {
                                "$ref": "#/components/schemas/inputSchema"
                            }
                        }
                    }
                },
                "parameters": [
                    {
                        "name": "token",
                        "in": "query",
                        "required": true,
                        "schema": {
                            "type": "string"
                        },
                        "description": "Enter your Apify token here"
                    }
                ],
                "responses": {
                    "200": {
                        "description": "OK"
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "inputSchema": {
                "type": "object",
                "required": [
                    "watches"
                ],
                "properties": {
                    "watches": {
                        "title": "URLs to monitor",
                        "type": "array",
                        "description": "One entry per thing you want to watch. Each entry supports:\n• url (required)\n• selector – CSS selector to watch just one element (e.g. \".price\"). Omit to watch the whole page's text.\n• label – a friendly name for this watch.\n• extract – \"text\" (default), \"number\" (parses a price/quantity), or \"html\".\n• notifyOn – \"change\" (default), \"increase\", \"decrease\", or \"contains\".\n• keyword – required when notifyOn is \"contains\" (e.g. \"in stock\")."
                    },
                    "onlyReportChanges": {
                        "title": "Only output when something changed",
                        "type": "boolean",
                        "description": "Recommended ON for alerting. On the very first run each watch is stored as a baseline and always shown so you can confirm the starting values.",
                        "default": true
                    },
                    "webhookUrl": {
                        "title": "Webhook URL (optional)",
                        "type": "string",
                        "description": "If set, WatchTower sends a JSON POST here for every detected change. Works with Slack, Zapier, Make, or your own endpoint."
                    },
                    "proxyConfiguration": {
                        "title": "Proxy (optional)",
                        "type": "object",
                        "description": "Optional. Most public pages need no proxy. Datacenter proxy is included in your Apify plan if a site blocks plain requests.",
                        "default": {
                            "useApifyProxy": false
                        }
                    }
                }
            },
            "runsResponseSchema": {
                "type": "object",
                "properties": {
                    "data": {
                        "type": "object",
                        "properties": {
                            "id": {
                                "type": "string"
                            },
                            "actId": {
                                "type": "string"
                            },
                            "userId": {
                                "type": "string"
                            },
                            "startedAt": {
                                "type": "string",
                                "format": "date-time",
                                "example": "2025-01-08T00:00:00.000Z"
                            },
                            "finishedAt": {
                                "type": "string",
                                "format": "date-time",
                                "example": "2025-01-08T00:00:00.000Z"
                            },
                            "status": {
                                "type": "string",
                                "example": "READY"
                            },
                            "meta": {
                                "type": "object",
                                "properties": {
                                    "origin": {
                                        "type": "string",
                                        "example": "API"
                                    },
                                    "userAgent": {
                                        "type": "string"
                                    }
                                }
                            },
                            "stats": {
                                "type": "object",
                                "properties": {
                                    "inputBodyLen": {
                                        "type": "integer",
                                        "example": 2000
                                    },
                                    "rebootCount": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "restartCount": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "resurrectCount": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "computeUnits": {
                                        "type": "integer",
                                        "example": 0
                                    }
                                }
                            },
                            "options": {
                                "type": "object",
                                "properties": {
                                    "build": {
                                        "type": "string",
                                        "example": "latest"
                                    },
                                    "timeoutSecs": {
                                        "type": "integer",
                                        "example": 300
                                    },
                                    "memoryMbytes": {
                                        "type": "integer",
                                        "example": 1024
                                    },
                                    "diskMbytes": {
                                        "type": "integer",
                                        "example": 2048
                                    }
                                }
                            },
                            "buildId": {
                                "type": "string"
                            },
                            "defaultKeyValueStoreId": {
                                "type": "string"
                            },
                            "defaultDatasetId": {
                                "type": "string"
                            },
                            "defaultRequestQueueId": {
                                "type": "string"
                            },
                            "buildNumber": {
                                "type": "string",
                                "example": "1.0.0"
                            },
                            "containerUrl": {
                                "type": "string"
                            },
                            "usage": {
                                "type": "object",
                                "properties": {
                                    "ACTOR_COMPUTE_UNITS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATASET_READS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATASET_WRITES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "KEY_VALUE_STORE_READS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "KEY_VALUE_STORE_WRITES": {
                                        "type": "integer",
                                        "example": 1
                                    },
                                    "KEY_VALUE_STORE_LISTS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "REQUEST_QUEUE_READS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "REQUEST_QUEUE_WRITES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATA_TRANSFER_INTERNAL_GBYTES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATA_TRANSFER_EXTERNAL_GBYTES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "PROXY_RESIDENTIAL_TRANSFER_GBYTES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "PROXY_SERPS": {
                                        "type": "integer",
                                        "example": 0
                                    }
                                }
                            },
                            "usageTotalUsd": {
                                "type": "number",
                                "example": 0.00005
                            },
                            "usageUsd": {
                                "type": "object",
                                "properties": {
                                    "ACTOR_COMPUTE_UNITS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATASET_READS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATASET_WRITES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "KEY_VALUE_STORE_READS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "KEY_VALUE_STORE_WRITES": {
                                        "type": "number",
                                        "example": 0.00005
                                    },
                                    "KEY_VALUE_STORE_LISTS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "REQUEST_QUEUE_READS": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "REQUEST_QUEUE_WRITES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATA_TRANSFER_INTERNAL_GBYTES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "DATA_TRANSFER_EXTERNAL_GBYTES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "PROXY_RESIDENTIAL_TRANSFER_GBYTES": {
                                        "type": "integer",
                                        "example": 0
                                    },
                                    "PROXY_SERPS": {
                                        "type": "integer",
                                        "example": 0
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}
```