changedetection.io
An open-source web app for monitoring page content, prices, stock status, and structured data, with alerts and self-hosted deployment.
changedetection.io is an open-source web app for monitoring websites and receiving alerts when their content changes. It can track price changes, restock status, conditional changes, PDF files, legal or other documents, JSON API responses, and new software or security updates. Notifications can be sent through Discord, Email, Slack, Telegram, webhooks, and many other formats. The interface can target specific page elements and apply filters such as XPath, JSONPath, jq, CSS selectors, regular expressions, trigger text, ignored text, and extracted text. Watches can use a fast non-JavaScript fetcher or a Chrome-based fetcher for JavaScript sites, with configurable check schedules, proxies, request methods, and screenshots attached to notifications. Optional AI features connect an LLM such as OpenAI, Gemini, Anthropic, Ollama, vLLM, LM Studio, or another OpenAI-compatible endpoint. Plain-language rules can ask the system to alert only when a price drops below a threshold or an item returns to stock, while AI summaries describe the concrete changes instead of showing only a raw diff. Browser Steps can fill fields, click buttons, sign in to sites, add products to carts, accept cookie dialogs, and refine searches before change detection; this requires a browser fetcher such as Playwright. The project also includes a restock and price-detection mode and a Chrome extension for adding the current page to an installation. The project can be tried with Docker Compose, a standalone Docker container, or the Python package. The README documents a local interface at http://127.0.0.1:5000 and a Windows installation path through the wiki. Browser-based monitoring needs the corresponding Chrome or Playwright setup, while the hosted subscription, proxies, and other managed services are separate from the self-hosted open-source project.