Change Detection Monitor

beginner

Web page change detection with notifications.

Overview

ChangeDetection.io is an open-source web monitoring tool that tracks changes on websites and web applications, alerting users when content modifications occur. Originally developed as a self-hosted alternative to commercial monitoring services, it provides granular control over what gets monitored, from entire pages to specific CSS selectors, with support for complex filtering and change detection algorithms that can ignore cosmetic updates while catching meaningful content changes. This monitoring stack combines ChangeDetection.io with Playwright browser automation and ntfy notification service to create a comprehensive change detection system. The Playwright component handles JavaScript-heavy sites and complex rendering scenarios that simple HTTP requests cannot capture, while ntfy provides a lightweight, self-hosted notification server that can deliver alerts through multiple channels including mobile push notifications, webhooks, and email integration. Homelab enthusiasts and small teams will find this stack particularly valuable for monitoring price changes, service status pages, job postings, or any web content that requires immediate attention when updated. The combination eliminates dependencies on external services while providing enterprise-grade monitoring capabilities that can scale from monitoring a handful of personal sites to hundreds of business-critical web resources.

Key Features

CSS selector-based monitoring for precise element tracking and change detection
Playwright browser engine integration for full JavaScript rendering and SPA support
Visual diff detection with screenshot comparison and highlighted change regions
XPath and JSONPath filtering for structured data monitoring and API endpoint changes
Regex pattern matching for content filtering and false positive reduction
Self-hosted ntfy notification server with topic-based message routing
Change detection threshold configuration to ignore minor cosmetic updates
Built-in proxy support through Playwright for geo-restricted content monitoring

Common Use Cases

1E-commerce price monitoring for competitor analysis and deal alerting
2Government website monitoring for permit applications and regulatory updates
3Job board monitoring for specific positions or company postings
4Service status page monitoring for third-party dependencies and SaaS providers
5Real estate listing monitoring for new properties in specific areas or price ranges
6News website monitoring for breaking news in specific categories or topics
7Software release monitoring for GitHub releases and changelog updates

Prerequisites

Docker host with minimum 2GB RAM for Playwright browser instances
Available ports 5000 and 8080 for web interface access
Persistent storage allocation for change detection history and notification cache
Network connectivity to target websites and any notification endpoints
Basic understanding of CSS selectors for advanced monitoring configuration
Mobile device or webhook endpoint configured for ntfy notifications

For development & testing. Review security settings, change default credentials, and test thoroughly before production use. See Terms

docker-compose.yml

1services: 
2  changedetection: 
3    image: ghcr.io/dgtlmoon/changedetection.io:latest
4    container_name: changedetection
5    restart: unless-stopped
6    ports: 
7      - "${CD_PORT:-5000}:5000"
8    environment: 
9      - PLAYWRIGHT_DRIVER_URL=ws://playwright:3000
10      - BASE_URL=http://localhost:${CD_PORT:-5000}
11    volumes: 
12      - changedetection_data:/datastore
13    depends_on: 
14      - playwright
15
16  playwright: 
17    image: browserless/chrome:latest
18    container_name: cd-playwright
19    restart: unless-stopped
20    environment: 
21      - DEFAULT_BLOCK_ADS=true
22      - DEFAULT_STEALTH=true
23
24  ntfy: 
25    image: binwiederhier/ntfy:latest
26    container_name: cd-ntfy
27    restart: unless-stopped
28    ports: 
29      - "${NTFY_PORT:-8080}:80"
30    volumes: 
31      - ntfy_cache:/var/cache/ntfy
32
33volumes: 
34  changedetection_data: 
35  ntfy_cache:

.env Template

.env

1# Change Detection
2CD_PORT=5000
3NTFY_PORT=8080

Usage Notes

1Change Detection at http://localhost:5000
2Ntfy at http://localhost:8080
3Add URLs to monitor
4Playwright for JS rendering

Individual Services(3 services)

Copy individual services to mix and match with your existing compose files.

changedetection

changedetection:
  image: ghcr.io/dgtlmoon/changedetection.io:latest
  container_name: changedetection
  restart: unless-stopped
  ports:
    - ${CD_PORT:-5000}:5000
  environment:
    - PLAYWRIGHT_DRIVER_URL=ws://playwright:3000
    - BASE_URL=http://localhost:${CD_PORT:-5000}
  volumes:
    - changedetection_data:/datastore
  depends_on:
    - playwright

playwright

playwright:
  image: browserless/chrome:latest
  container_name: cd-playwright
  restart: unless-stopped
  environment:
    - DEFAULT_BLOCK_ADS=true
    - DEFAULT_STEALTH=true

ntfy

ntfy:
  image: binwiederhier/ntfy:latest
  container_name: cd-ntfy
  restart: unless-stopped
  ports:
    - ${NTFY_PORT:-8080}:80
  volumes:
    - ntfy_cache:/var/cache/ntfy

Quick Start

terminal

1# 1. Create the compose file
2cat > docker-compose.yml << 'EOF'
3services:
4  changedetection:
5    image: ghcr.io/dgtlmoon/changedetection.io:latest
6    container_name: changedetection
7    restart: unless-stopped
8    ports:
9      - "${CD_PORT:-5000}:5000"
10    environment:
11      - PLAYWRIGHT_DRIVER_URL=ws://playwright:3000
12      - BASE_URL=http://localhost:${CD_PORT:-5000}
13    volumes:
14      - changedetection_data:/datastore
15    depends_on:
16      - playwright
17
18  playwright:
19    image: browserless/chrome:latest
20    container_name: cd-playwright
21    restart: unless-stopped
22    environment:
23      - DEFAULT_BLOCK_ADS=true
24      - DEFAULT_STEALTH=true
25
26  ntfy:
27    image: binwiederhier/ntfy:latest
28    container_name: cd-ntfy
29    restart: unless-stopped
30    ports:
31      - "${NTFY_PORT:-8080}:80"
32    volumes:
33      - ntfy_cache:/var/cache/ntfy
34
35volumes:
36  changedetection_data:
37  ntfy_cache:
38EOF
39
40# 2. Create the .env file
41cat > .env << 'EOF'
42# Change Detection
43CD_PORT=5000
44NTFY_PORT=8080
45EOF
46
47# 3. Start the services
48docker compose up -d
49
50# 4. View logs
51docker compose logs -f

One-Liner

Run this command to download and set up the recipe in one step:

terminal

1curl -fsSL https://docker.recipes/api/recipes/changedetection-stack/run | bash

Troubleshooting

ChangeDetection shows 'Playwright connection failed': Verify playwright container is running and check PLAYWRIGHT_DRIVER_URL environment variable matches service name
Memory errors in Playwright container: Increase Docker memory limits or reduce concurrent monitoring jobs in ChangeDetection settings
ntfy notifications not received: Check ntfy topic subscription on client device and verify container port mapping for external access
JavaScript-heavy sites not detecting changes: Enable Playwright renderer in monitor settings and increase page load wait time
False positive change alerts: Implement CSS filters to exclude dynamic elements like timestamps, ads, or user counters
ChangeDetection data loss after restart: Verify changedetection_data volume is properly mounted and has write permissions

Community Notes

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