# Website Change Monitor: Text Diffs & Alerts (`iveeeeeen/website-change-monitor-diff`) Actor

Monitor web pages for changes and see exactly what changed: added/removed lines, change %, new links, keyword appear/disappear alerts, Slack-compatible webhooks. CSS selector + regex ignore rules. $0.002 per page check.

- **URL**: https://apify.com/iveeeeeen/website-change-monitor-diff.md
- **Developed by:** [Ivan Alvarado](https://apify.com/iveeeeeen) (community)
- **Categories:** Automation, Developer tools, SEO tools
- **Stats:** 2 total users, 1 monthly users, 0.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

$2.00 / 1,000 page checkeds

This Actor is paid per event. You are not charged for the Apify platform usage, but only a fixed price for specific events.

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

## What's an Apify Actor?

An Actor is a serverless cloud program that runs on the Apify platform. It has two run modes.
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.

Apify vocabulary and the platform model are defined once, in the agent quickstart at https://apify.com/agents.md.

## 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.

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 examples already wired to this Actor's own input schema, see the [API](#api) section below.

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`).

# README

## Website Change Monitor: Track Page Changes with Text Diffs

**Watch any public web page and find out exactly what changed: added lines, removed lines, change percentage and new links.** The first run stores a baseline. Each scheduled run after that compares against it. Connect a webhook, email, Slack or Zapier integration to get alerts.

### Features

- **Readable diffs**: `addedLines` and `removedLines`, not just "changed: true"
- **Watch part of a page** with a CSS selector (e.g. `#pricing`, `.release-list`, `table.prices`)
- **Noise control**: regex ignore rules (timestamps, counters) and a minimum changed-characters threshold
- **Smart default extraction**: main content with nav, header, footer and scripts removed
- **Keyword alerts**: `watchKeywords` reports when words like "sold out", "v3.14" or "deprecated" appear or disappear
- **Built-in alerts**: `webhookUrl` POSTs a JSON summary of changes (with a Slack/Discord-compatible `text` field) to Slack, Zapier, Make or n8n
- **New-link detection**: spot new blog posts, products or documents linked from a page
- **Several monitors**: separate baselines per `monitorName`, stored in your own named key-value store
- `outputOnlyChanges` keeps the dataset empty unless something changed, which is ideal for "notify only on change" workflows

### Typical setups

- **Competitor pricing pages**: selector `#pricing`, scheduled daily
- **Release and changelog pages**: watch for new versions
- **Terms, privacy and policy pages**: compliance monitoring
- **Government and regulator notice pages**, job boards' "careers" pages, stock or availability text

### Input example

```json
{ "urls": ["https://www.python.org/downloads/"], "cssSelector": ".download-list-widget", "ignorePatterns": ["\\d+ (minutes|hours) ago"], "outputOnlyChanges": true, "monitorName": "python-releases" }
```

### Output example (change detected)

```json
{ "url": "https://example.com/pricing", "status": "changed", "changed": true, "changePercent": 3.2,
  "addedLines": ["Pro plan $29/month"], "removedLines": ["Pro plan $25/month"], "newLinks": [], "previousCheckAt": "2026-10-20T09:00:00.000Z", "checkedAt": "2026-10-21T09:00:00.000Z" }
```

`status` is `baseline` (first run), `changed`, `unchanged` or `error`.

### Pricing (pay per event)

**$0.002 per page check** ($2 per 1,000 checks). Pages that fail to load are not charged. Checking 10 pages daily costs about $0.60 a month, far less than per-site monitors that charge around $0.10 per check.

### Notes

It reads server-rendered HTML and does not run JavaScript, so it's fast and cheap. Pages whose content loads only through JavaScript may show little text, so pick a selector that appears in the server HTML.

# Actor input Schema

## `urls` (type: `array`):

Public page URLs. The first run stores a baseline; later runs report changes.

## `cssSelector` (type: `string`):

Only watch this part of the page, e.g. #pricing or .release-list. Empty = main content (nav/header/footer removed).

## `ignorePatterns` (type: `array`):

Regexes removed before comparison, e.g. \d+ minutes ago or Updated: .\*

## `minChangedChars` (type: `integer`):

Treat smaller changes as unchanged (reduces noise).

## `outputOnlyChanges` (type: `boolean`):

Skip 'unchanged' results in the dataset (baselines, changes and errors are always saved). Great for webhook alerts on non-empty datasets.

## `monitorName` (type: `string`):

Separate baseline memory per monitor (stored in named key-value store 'website-change-monitor-state').

## `watchKeywords` (type: `array`):

Report when any of these words/phrases appear or disappear (e.g. 'sold out', 'v3.14', 'deprecated').

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

If any page changed, POST a JSON summary here. Works with Slack/Discord-compatible incoming webhooks (includes a 'text' field), Zapier, Make, n8n.

## Actor input object example

```json
{
  "urls": [
    "https://www.python.org/downloads/",
    "https://news.ycombinator.com"
  ],
  "minChangedChars": 1,
  "outputOnlyChanges": false,
  "monitorName": "default"
}
```

# Actor output Schema

## `changes` (type: `string`):

No description

## `all` (type: `string`):

No description

# 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 = {
    "urls": [
        "https://www.python.org/downloads/",
        "https://news.ycombinator.com"
    ]
};

// Run the Actor and wait for it to finish
const run = await client.actor("iveeeeeen/website-change-monitor-diff").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 = { "urls": [
        "https://www.python.org/downloads/",
        "https://news.ycombinator.com",
    ] }

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

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

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

```

## CLI example

```bash
echo '{
  "urls": [
    "https://www.python.org/downloads/",
    "https://news.ycombinator.com"
  ]
}' |
apify call iveeeeeen/website-change-monitor-diff --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "type": "http",
            "url": "https://mcp.apify.com/?tools=fetch-actor-details,iveeeeeen/website-change-monitor-diff"
        }
    }
}
```

The hosted server signs you in with OAuth on first connect, so no API token belongs in this config. Clients without OAuth support can send an `Authorization: Bearer <APIFY_API_TOKEN>` header instead, using a token from API & Integrations in Apify Console (https://console.apify.com/settings/integrations).

## OpenAPI specification

Download the OpenAPI definition: https://api.apify.com/v2/actors/qAE5q2lUKNYvZjRwq/builds/kiYb6olJT5YA0zuub/openapi.json