Show HN: I built a tool that watches webpages and exposes changes as RSS
Site Spy introduces a new web monitoring tool that tracks specific elements on webpages and surfaces changes via RSS feeds or direct alerts, sparking significant interest among Hacker News users. Built to address common frustrations like missed visa appointments, the tool's focus on element-level tracking and visual diffs resonated with those needing precise updates. The discussion quickly turned to comparing it with existing solutions, validating the demand for such a service, and debating the utility of RSS in a notification-heavy world.
The Lowdown
Site Spy is a new web monitoring tool designed to track changes on webpages and notify users when content updates. Born from the author's personal experience of missing a crucial visa appointment update, the service offers advanced features beyond simple full-page monitoring.
- Element-Level Tracking: Users can select and monitor specific elements on a page (like prices, stock status, or headlines) rather than the entire page, reducing noise.
- Visual Diffs & History: Provides a clear visual diff highlighting what changed (additions in green, removals in red) and maintains a full snapshot timeline for historical comparisons.
- Flexible Notifications: Offers various alert methods including browser push notifications, email, Telegram, and, notably, RSS feeds.
- AI Integration: Includes an MCP server for integration with AI agents like Claude and Cursor, allowing automated monitoring and change summarization within AI chats.
- Cross-Browser & Device Support: Available as a Chrome/Firefox extension and a web dashboard with synced data across devices.
- Tiered Pricing: Offers a free tier for basic monitoring, with paid plans for more watches, faster recheck intervals, and extended history.
The tool aims to provide a user-friendly, browser-first workflow for keeping tabs on dynamic web content, catering to both casual users and those with critical monitoring needs.
The Gossip
Alerting Preferences & RSS Revival
The author's question about the utility of RSS sparked a lively debate. Many commenters expressed a desire for both RSS and direct alerts (email, push, Telegram), with RSS favored for passive content consumption and direct alerts reserved for urgent, action-required updates. There was a nostalgic sentiment for RSS, with some lamenting its decline and others highlighting its niche but dedicated following for integrating updates into custom workflows.
Technical Hurdles & Handling Modern Web
A primary concern raised was how Site Spy handles modern, JavaScript-heavy, and dynamically rendered websites, as well as sites with aggressive anti-bot measures. The author clarified that Site Spy uses a 'real browser flow' to better manage JS-rendered pages, emphasizing that anti-bot protection and complex login flows are typically more challenging than JavaScript itself. This addresses a common pain point for traditional web scrapers and monitors.
Competition & Unique Value Proposition
Commenters quickly pointed to existing alternatives, including open-source projects like `changedetection.io` and `urlwatch`, and other SaaS offerings like `AnyTracker` and `visualping.io`. The author acknowledged these, positioning Site Spy's unique value in its streamlined browser-first workflow, intuitive visual element picker, and integrated dashboard, which aims to make precise monitoring and change inspection (diffs, history, RSS) easily accessible with minimal setup.
Practical Applications & User Enthusiasm
Many users expressed strong enthusiasm for Site Spy, highlighting practical and often frustrating real-world scenarios where such a tool is invaluable. Examples included tracking changes in government regulations (e.g., German laws, wildlife agency updates), monitoring privacy policies, and even potential uses for financial or market data. The element-level tracking was particularly praised for its ability to cut through noise on complex pages, making it ideal for specific, critical updates.