# Website Change Monitor — Diff & Webhook Alerts (`wsgcjj/change-monitor`) Actor Monitor any web page for content changes. Get structured diff reports showing exactly what changed (added/removed lines). Supports CSS selectors, webhook notifications, and persistent content tracking via KV store. Ideal for competitor monitoring, price tracking, and policy change detection. - **URL**: https://apify.com/wsgcjj/change-monitor.md - **Developed by:** [陈俊杰](https://apify.com/wsgcjj) (community) - **Categories:** Developer tools, AI - **Stats:** 0 total users, 0 monthly users, 100.0% runs succeeded, NaN bookmarks - **User rating**: No ratings yet ## Pricing Pay per usage This Actor is paid per platform usage. The Actor is free to use, and you only pay for the Apify platform usage, which gets cheaper the higher subscription plan you have. Learn more: https://docs.apify.com/platform/actors/running/actors-in-store#pay-per-usage ## 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 ## Website Change Monitor Monitor web pages for content changes and receive structured diff reports. Ideal for: - **Competitor monitoring** — track changes on competitor landing pages, pricing, or feature listings. - **Policy change detection** — get alerted when terms of service, privacy policies, or regulatory pages update. - **Price tracking** — detect price changes on product pages. - **News & blog monitoring** — know when new articles or updates are published. ### How it works 1. Set the **URL** you want to monitor (and optionally a **CSS selector** to scope checking). 2. On each run, the Actor fetches the page, extracts readable text, and compares it against the previous run's content (stored automatically in the Actor's key-value store). 3. A structured diff report is saved to the default dataset with: - `changed` — boolean flag - `diff` — unified diff string (`+` lines added, `-` lines removed) - `added` / `removed` — lists of changed lines - `checked_at` — timestamp - `content_hash` — SHA256 for quick cache-busting checks 4. Optionally, configure a **webhook URL** to receive POST notifications only when a change is detected. ### Input | Field | Type | Required | Description | |-------|------|----------|-------------| | `url` | string | ✅ | Full URL of the page to monitor | | `selector` | string | ❌ | CSS selector to limit monitoring to a specific element | | `webhook_url` | string | ❌ | URL to POST change notifications to | | `previous_content` | string | ❌ | Previous content override (falls back to stored value) | ### Output Each run produces one dataset entry with the following structure: ```json { "changed": true, "diff": "+ New pricing: $49/mo\n- Old pricing: $39/mo", "added": ["New pricing: $49/mo"], "removed": ["Old pricing: $39/mo"], "url": "https://example.com/pricing", "checked_at": "2026-05-29T12:00:00+00:00", "content_hash": "a1b2c3d4e5f6..." } ```` ### Pricing - **$0.01 per check run** — webhook notifications included at no extra cost. - No hidden fees, no per-result surcharges. ### Example usage #### Basic monitoring ```json { "url": "https://example.com/pricing" } ``` #### Scoped monitoring + webhook ```json { "url": "https://example.com/pricing", "selector": "#pricing-table", "webhook_url": "https://hooks.slack.com/services/xxx/yyy/zzz" } ``` ### Storage - **Previous content** is automatically persisted in the Actor's key-value store under the key `last_content`. - **Diff results** are pushed to the default dataset and can be exported as JSON, CSV, Excel, etc. - The content hash enables external systems to quickly check if content changed without re-reading the full diff. ### Development ```bash ## Install dependencies pip install -r requirements.txt ## Run locally (requires Apify token) python -m src ``` # Actor input Schema ## `url` (type: `string`): The full URL of the webpage you want to monitor for content changes. ## `selector` (type: `string`): Optional CSS selector to scope monitoring to a specific part of the page (e.g. '.main-content', '#pricing-table'). Leave empty to monitor the entire page. ## `webhook_url` (type: `string`): Optional URL to receive a POST notification when a change is detected. The payload will include the full diff result. ## `previous_content` (type: `string`): Previous page content to compare against. Leave empty to use the stored 'last\_content' value from the previous run. ## Actor input object example ```json {} ``` # Actor output Schema ## `changed` (type: `string`): Whether a content change was detected compared to the previous run ("true" or "false"). ## `diff` (type: `string`): Unified diff showing lines added (+) and removed (-) between the previous and current content. ## `added` (type: `string`): List of text lines that were added since the last check (newline-separated). ## `removed` (type: `string`): List of text lines that were removed since the last check (newline-separated). ## `url` (type: `string`): The URL that was checked. ## `checked_at` (type: `string`): ISO8601 timestamp of when the check was performed. ## `content_hash` (type: `string`): SHA256 hash of the current extracted content, useful for quick equality checks. # 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 '' with your token const client = new ApifyClient({ token: '', }); // Prepare Actor input const input = {}; // Run the Actor and wait for it to finish const run = await client.actor("wsgcjj/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 '' with your token. client = ApifyClient("") # Prepare the Actor input run_input = {} # Run the Actor and wait for it to finish run = client.actor("wsgcjj/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 '{}' | apify call wsgcjj/change-monitor --silent --output-dataset ``` ## MCP server setup ```json { "mcpServers": { "apify": { "command": "npx", "args": [ "mcp-remote", "https://mcp.apify.com/?tools=wsgcjj/change-monitor", "--header", "Authorization: Bearer " ] } } } ``` ## OpenAPI specification ```json { "openapi": "3.0.1", "info": { "title": "Website Change Monitor — Diff & Webhook Alerts", "description": "Monitor any web page for content changes. Get structured diff reports showing exactly what changed (added/removed lines). Supports CSS selectors, webhook notifications, and persistent content tracking via KV store. Ideal for competitor monitoring, price tracking, and policy change detection.", "version": "0.0", "x-build-id": "QlIAaCq6qCdas7hhm" }, "servers": [ { "url": "https://api.apify.com/v2" } ], "paths": { "/acts/wsgcjj~change-monitor/run-sync-get-dataset-items": { "post": { "operationId": "run-sync-get-dataset-items-wsgcjj-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": { "$ref": "#/components/schemas/inputSchema" } } } }, "parameters": [ { "name": "token", "in": "query", "required": true, "schema": { "type": "string" }, "description": "Enter your Apify token here" } ], "responses": { "200": { "description": "OK" } } } }, "/acts/wsgcjj~change-monitor/runs": { "post": { "operationId": "runs-sync-wsgcjj-change-monitor", "x-openai-isConsequential": false, "summary": "Executes an Actor and returns information about the initiated run in response.", "tags": [ "Run Actor" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$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": { "$ref": "#/components/schemas/runsResponseSchema" } } } } } } }, "/acts/wsgcjj~change-monitor/run-sync": { "post": { "operationId": "run-sync-wsgcjj-change-monitor", "x-openai-isConsequential": false, "summary": "Executes an Actor, waits for completion, and returns the OUTPUT from Key-value store in response.", "tags": [ "Run Actor" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$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": [ "url" ], "properties": { "url": { "title": "URL to monitor", "type": "string", "description": "The full URL of the webpage you want to monitor for content changes." }, "selector": { "title": "CSS selector (optional)", "type": "string", "description": "Optional CSS selector to scope monitoring to a specific part of the page (e.g. '.main-content', '#pricing-table'). Leave empty to monitor the entire page." }, "webhook_url": { "title": "Webhook URL (optional)", "type": "string", "description": "Optional URL to receive a POST notification when a change is detected. The payload will include the full diff result." }, "previous_content": { "title": "Previous content (optional)", "type": "string", "description": "Previous page content to compare against. Leave empty to use the stored 'last_content' value from the previous run." } } }, "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 } } } } } } } } } } ```