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SSL certificate monitoring

Your cert
won't expire
on a Saturday.

Otterwatch checks your sites once a day and emails you when a certificate is about to expire — or when your site goes quiet. That's the whole product.

Free plan No credit card Plain-text email
Otis the otter park ranger, the Otterwatch mascot
From Otis
Hi — your certificate for apple.com expires in 7 days. Time to renew it.
— Otis at Otterwatch
Free tool

Just want to spot-check a site?

Paste a domain, see its cert. No signup, no tracking.

Check a site
The dashboard

Everything you need on one page.

Each site shows its status, when its certificate expires, and when we last checked. That's the whole interface — no graphs, no tabs, no settings to fiddle with.

Otterwatch dashboard showing five monitored sites with mixed statuses: cert invalid, cert expired, down, and up.
How it works

One quiet daily check.

01

Add a site

Paste the URL. That's it — no DNS or HTML changes needed.

02

We check daily

Once a day, Otis runs the two checks. No scheduling for you to set.

03

Email if something changes

Otherwise, silence. You won't hear from us if everything is fine.

What we watch

Two checks, done well.

We don't do synthetic transactions or 17-region uptime. We do the two things that actually wake you up at 4am.

SSL certificates

We read your cert each morning and email you at 23, 14, 7 and 1 days before it expires. If it's already expired, you'll hear about it within the hour.

Reachability

A daily HTTP check from a quiet box on the east coast. Anything other than 2xx counts as down. We re-check three times before we email you.

Plain-text email

No HTML, no tracking pixels, no marketing fluff. A note from Otis with what changed and a link to the dashboard — where you can stop alerts anytime.

Pricing

Free forever. Pro when you're ready.

Five domains, watched daily, no card and no clock. Pro is the deeper SSL and security watching, on its way.

Free FreeForeverNo card
$0

forever, no credit card

  • 5 monitored domains
  • Daily SSL + reachability checks
  • Expiry alerts at 30, 7, and 1 day
  • Plain-text email from Otis
Pro ProComing soon
Pricing soon

everything in Free, plus the deeper watching

  • Cert change-detection — catch an unexpected swap
  • CT issuance monitoring — any new cert, the moment it's issued
  • More monitors (10–25)
  • Slack & webhook alerts

Already watching with us? I'll email you when Pro's ready. — Otis

Start watching

Put one site on the trail.

Sign in with your email — we'll mail you a one-time link, no password to remember. Add a site, and that's onboarding.

Send me a magic link
Otis, the Otterwatch otter