Price drops, restocks, job postings, government announcements, competitor edits - changedetection.io watches web pages and alerts you the moment anything changes, down to PDF text and checksums. Point it at a URL, set a check interval, and precise filters decide what counts as a change: a Visual Selector targets page elements by pointing and clicking, CSS selectors and XPath narrow scope, trigger-text and ignore-text rules (with regex support) cut noise, and JSONPath or jq handles API responses. A dedicated re-stock and price detection mode extracts product metadata and fires on thresholds - alert only when the price drops below your target or the percentage change exceeds a limit. JavaScript-heavy sites render through a real Chrome browser via Playwright, with the ability to execute JS steps first (log in, click, scroll) before extracting text. Notifications reach 85+ services through Apprise - Discord, Slack, Telegram, email, webhooks - optionally with a screenshot of the changed page, and AI-powered summaries (any OpenAI-compatible endpoint, including local Ollama) describe what changed. Per-watch proxies, custom headers, and POST/GET control cover hostile targets. Apache-2.0 licensed with local file-based storage: the URLs you monitor and why stay entirely your business.