SSL/TLS Certificate Lookup

Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted

SSL/TLS Certificate for karuizawa-on.com

Hostname mismatch
Issued by (CA)
Let's Encrypt
Subject
www.karuizawa-on.com
Valid from
Jun 30, 2026
Valid until
Sep 28, 2026 (43 days remaining)
Public key
RSA 2048-bit
Serial
0543761243990A4AE900192DA98E5653F068
SHA-256 fingerprint
05:EE:F5:EF:82:13:97:CC:8C:54:4E:CD:BD:FF:FB:2A:9C:DE:8F:AE:F4:38:CB:47:1E:19:06:F7:98:C6:04:ED
Chain
YR2 → Root YR → ISRG Root X1
Subject Alternative Names (1)
www.karuizawa-on.com

Certificate Authority Authorization (CAA)

No CAA policy is published for this domain — any certificate authority may issue for it.

This certificate has been served since Aug 1, 2026.

Never get surprised by karuizawa-on.com's certificate expiring

This is today's certificate. Turn on monitoring and we'll watch karuizawa-on.com continuously, notifying you the moment anything moves across all three signals:

Uptime

We visit the site from multiple regions worldwide and email you within minutes if it goes down, with a per-region breakdown so a real outage stands out from a regional blip.

DNS changes

We watch NS, MX, CAA, DNSSEC, CNAME and A/AAAA records, and identify the host, network, and ASN behind them, so a real migration or hijack stands out from routine noise.

TLS certificate

We warn you 30, 14, 7, and 1 days before it expires, and flag it if the issuing authority changes or the certificate is unexpectedly replaced.

Monitor this certificate free

Free for your first domain: uptime, DNS, and certificate together. No credit card.