SignalWatch

URL change monitor

SignalWatch

Know the second a page changes.

Monitor any public URL. Email, Slack, Discord, or a signed JSON webhook when the text drifts or the fetch fails — with a diff of what changed. Point a CSS selector at the price, not the cookie banner.

No card. Dashboard login uses your password. API key is shown once for scripts.

Log in API docs

How it works

  1. 01
    Add a URLCompetitors, status pages, pricing pages, changelogs — anything public. See use cases.
  2. 02
    We fingerprint itScheduled fetches hash the visible text. Scope it with a CSS selector, strip timestamps with an ignore regex, or set a minimum change size so noise never pages you.
  3. 03
    You see what changedEmail, Slack, Discord, or a signed JSON webhook lands with a unified diff of the text. Every event is kept in the monitor's history. Wire it into n8n, a script, or CI.

Pricing

Start free. Diffs, email and Slack are included on every plan — you pay for more URLs and faster checks.

Free

$0

  • 3 monitors · every 15 min
  • Diff of what changed, 45-day history
  • Email, Slack, Discord, or signed JSON webhook
  • CSS selector, ignore regex, minimum-change filter
  • Change, down and recovery events
Create account

Pro

$12/mo

  • 50 monitors · every 5 min
  • Everything in Free
  • Watch whole competitor sites, not just one page
  • Email support that actually answers
Upgrade — $12/mo

Business

$29/mo

  • 500 monitors · every 2 min
  • Everything in Pro
  • For operators watching many public pages
  • Bulk create over the API
Upgrade — $29/mo

Cancel any time from the billing portal. 14-day refund on the first payment if it does not do the job. Prices in USD, tax handled at checkout by Creem.

FAQ

What does SignalWatch monitor?

Any public HTTP(S) URL you are allowed to fetch. SignalWatch fetches the page on a schedule, fingerprints the response body, and fires your webhook when it changes or fails. It does not bypass logins, paywalls, or CAPTCHAs.

Do I need a credit card for the free plan?

No. Create an account with your email and a password, then start with three monitors. An API key is shown once if you want the REST API.

How do alerts work?

Per monitor, pick email, a Slack incoming webhook, a Discord webhook, or any HTTPS JSON endpoint. When content changes, the fetch fails, or it comes back, SignalWatch sends the event, URL, status code and a unified diff of the text that changed. JSON webhooks carry an X-SignalWatch-Signature HMAC header and retry on failure. Hit “Send test alert” in the dashboard to confirm delivery before a real change happens.

How do I stop timestamps and “3 minutes ago” from triggering alerts?

Three tools, all on the free plan: a CSS selector to hash only the region you care about, an ignore regex that strips matching text before hashing, and a minimum-change filter that skips edits smaller than a percentage of the text. The diff in each alert shows you exactly what tripped it.

Is SignalWatch a Visualping or Distill alternative?

Yes if you want an API and a JSON webhook instead of screenshot emails. Visualping and Distill are stronger for pixel diffs and logged-in pages. SignalWatch is stronger for automation on public URLs. Full comparison: alternatives.

Can I use this without the dashboard?

Yes. Everything is available over the REST API with an X-API-Key header. OpenAPI docs live at /docs.

Is my data secure?

Traffic is HTTPS-only. Dashboard sessions use HttpOnly Secure cookies. API access uses per-account keys you can rotate anytime.

How do I get help?

Email [email protected] — we read every message.