I built Site Spy after missing a visa appointment slot because a government page changed and I didn’t notice for two weeks.

It watches webpages for changes and shows the result like a diff. The part I think HN might find interesting is that it can monitor a specific element on a page, not just the whole page, and it can expose changes as RSS feeds.

So instead of tracking an entire noisy page, you can watch just a price, a stock status, a headline, or a specific content block. When it changes, you can inspect the diff, browse the snapshot history, or follow the updates in an RSS reader.

It’s a Chrome/Firefox extension plus a web dashboard.

Main features:

- Element picker for tracking a specific part of a page

- Diff view plus full snapshot timeline

- RSS feeds per watch, per tag, or across all watches

- MCP server for Claude, Cursor, and other AI agents

- Browser push, Email, and Telegram notifications

Chrome: https://chromewebstore.google.com/detail/site-spy/jeapcpanag...

Firefox: https://addons.mozilla.org/en-GB/firefox/addon/site-spy/

Docs: https://docs.sitespy.app

I’d especially love feedback on two things:

- Is RSS actually a useful interface for this, or do most people just want direct alerts?

- Does element-level tracking feel meaningfully better than full-page monitoring?

user:	breadcat
created:	March 11, 2026
karma:	1