The Witness
When a page updates, you understand why.
15 followers
When a page updates, you understand why.
15 followers
Track any public URL. It takes screenshots on a schedule, filters out noise like cookie banners and ad rotations, and uses AI to tell you what actually changed in plain English. Alerts land in Slack, Discord, Telegram, or email. Free for 3 monitors.
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I'm Saul. I spent years building Android apps for other people, and The Witness is the first thing I built entirely for myself.
The problem was dumb but real: I was checking the same set of pages every morning, trying to remember if that number was always €49 or if it used to be €39. I tried existing monitoring tools but they just said "something changed" with a raw HTML diff. Useless if you don't want to read markup at 7am.
So I built something different. The Witness takes full-page screenshots with Playwright, extracts the actual text, filters out noise (cookie banners, timestamps, ad rotations that trigger false positives constantly), and runs a two-pass Gemini Vision analysis. You don't get a diff. You get a short brief: what changed, how significant it is on a 0-100 scale, and whether you should care.
The stack is Node.js + Playwright + BullMQ + Gemini. I designed it with this dark "noir observatory" UI because I wanted it to feel like an intelligence tool, not another pastel SaaS dashboard. Probably spent too much time on the design, but when I was doing android I was very enthusiastic about delightful UI experiences, so I never see it well enough.
Free: 3 monitors, checks every 6 hours, no card needed. Pro: $9/mo for 25 monitors with hourly checks and Slack/Discord/Telegram alerts. Agency: $29/mo for 100 monitors at 15-min intervals.
Would love to know what URL you'd point it at first. I read every comment.