I built a tool that watches webpages and exposes changes as RSS
Details
- External ID
- 47337607
- Source
- HN
- Company
- —
- Product
- I built a tool that watches webpages and exposes changes as RSS
- Website domain
- sitespy.app
- Launched
- March 11, 2026
- Cohort
- —
- Upvotes
- 320
- Upvotes percentile
- 0.981549815498155
- Tags
- —
- Fetched at
- Sept. 7, 2026, 9:26 p.m.
- Updated at
- Sept. 7, 2026, 9:26 p.m.
Description
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 notificationsChrome: https://chromewebstore.google.com/detail/site-spy/jeapcpanag...Firefox: https://addons.mozilla.org/en-GB/firefox/addon/site-spy/Docs: https://docs.sitespy.appI’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?
Enrichment
- Theme
- financial intelligence and trading tools
- Vertical
- Horizontal
- Function
- Workflow automation
- Audience
- B2B
- AI stance
- Not AI
- Project type
- Hobby / open-source project
- Normalized one-liner
- webpage monitoring tool that outputs changes as rss feeds
- Manually corrected
- False
Could you build this?
Yes The product consists of a browser extension to pick CSS selectors, a periodic headless fetcher (e.g., Playwright or basic HTTP requests), a diff engine, and an RSS feed generator.
Discussion
20 comments analyzed.
Competitors mentioned: changedetection.io (open source alternative), Klaxon (self-hosted monitoring tool), Custom GitHub Actions crawlers
Concerns raised: Insufficient attribution to changedetection.io fork origins, Telemetry collection on user emails without clear disclosure, CSS selectors break on sites with auto-generated class names, Captcha and anti-bot challenges cannot be handled, Auth-gated content (Instagram, paywalled pages) requires workarounds
Feature requests: Semantic element selectors ([data-testid], aria-label) instead of CSS paths, AI-assisted interaction to find elements without brittle selectors, Proxy rotation for geo-restricted content and rate limiting, Better handling of auth-gated and paywalled content, LLM semantic targeting for selector breakage detection
Competitors
Other products that read as similar to this one — 184 launches clear the similarity bar, closest 8 shown.
Attention rank: #3 of 185 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).
Launched 123 days after the earliest competitor.
- RSS.Style · hn · 2026-01-12 · 6 upvotes · similarity 0.49
- Watcher · ph · 2026-09-27 · 2 upvotes · similarity 0.46
- Trader News · hn · 2026-09-24 · 25 upvotes · similarity 0.46
- PageHarbor · ph · 2026-09-30 · 1 upvotes · similarity 0.45
- I built a fast RSS reader in Zig · hn · 2025-12-16 · 90 upvotes · similarity 0.43
- ScoutFox · hn · 2026-07-23 · 6 upvotes · similarity 0.43
- StackFollow · ph · 2026-09-09 · 3 upvotes · similarity 0.42
- PingCatchAI · ph · 2026-09-18 · 1 upvotes · similarity 0.41
Other launches for this product
- No other launches for this product.
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