changedetection.io

changedetection.io is a powerful yet simple open-source website change detection and monitoring platform. It tracks changes on any web page and sends alerts via email, Discord, Slack, Telegram, Matrix, Pushover, and many more notification channels.

Unlike cloud-only competitors, changedetection.io can be fully self-hosted with Docker, giving you complete control over your data and monitoring. It supports visual change detection, content filtering with CSS and XPath selectors, JSON API monitoring, RSS feed generation, and restock alerts for e-commerce sites.

The tool excels at tracking price drops, job listings, competitor updates, website defacement, and any content changes across the web. With over 31,000 GitHub stars, it is one of the most popular and actively maintained open-source monitoring tools available.