OneTimeSuite Blog · 2026

Certwatch vs SSLMate-style SSL monitors: Open Source vs Subscription

Certwatch and SSLMate-style SSL monitors solve the same problem from opposite directions: one is source-available software you can own outright for $24, the other is a subscription at $10–20/mo run entirely on someone else's servers.

Head to head

CertwatchSSLMate-style SSL monitors
Price$24 once$10–20/mo
3 years, 50 domains$24$360–720
Handshake checks (expiry, chain, keys)YesYes
Domain (WHOIS) expiryYes, best-effortSometimes
Email + webhook alertsYesYes
Data on your serverYesNo
Domain limitsNoneUsually tiered
Source you can readYes, MITNo

What Certwatch does well

  • Traffic-light dashboard — Green over 30 days, yellow at 30 or under, red under 7 days, or for expired, invalid or unreachable hosts.
  • Real TLS handshake checks — Node tls checks expiry, issuer, SAN list, chain validity, self-signed certs and weak keys (RSA under 2048, EC under 224).
  • Domain WHOIS expiry — Best-effort registry lookups so the domain registration itself does not lapse either.
  • Threshold alerts — Configurable days (default 30, 14, 7, 1) via webhook and SMTP email, with exactly one alert per threshold per certificate.

What SSLMate-style SSL monitors still does better

There's a real reason SSLMate-style SSL monitors costs what it does: a bigger team, broader integrations and dedicated support behind it. If that ecosystem is genuinely what you need, it's worth paying for.

Which one should you pick

If your workflow depends on SSLMate-style SSL monitors's specific integrations or you'd rather not run anything yourself, stay put — that's a legitimate call. If you're comfortable owning the tool and want to stop paying $10–20/mo for a job your own hardware can do, Certwatch pays for itself and then some: two months of a paid SSL monitor covers Certwatch, and one cert it saves from expiring covers the 2am page it would have cost you.

Try Certwatch — $24, once

Real TLS handshake checks on a schedule with 30/14/7/1-day email and webhook alerts.