About This Launch
SignalWatch watches public URLs and sends a unified text diff when the page changes or the fetch fails. Alerts go by email, Slack, Discord, or an HMAC-signed JSON webhook. Free for 3 monitors every 15 minutes. Built for people watching competitor pricing, status pages, and changelogs without running their own crawler.
Screenshots
Why I Built This
Hosted change monitors were built around screenshots and inbox emails. SignalWatch is the thinner version: hash the visible text on a public URL and deliver the diff, including on the free plan, without self-hosting a crawler.
Launch Details
CategoryDeveloper Tools
StageLive
ListedSeptember 24, 2026