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 4comfort.cz

Valid
Issued by (CA)
Let's Encrypt
Subject
4comfort.cz
Valid from
Sep 12, 2026
Valid until
Dec 11, 2026 (71 days remaining)
Public key
RSA 2048-bit
Serial
06047D61BA12EE024C2D5D7433FFF9D558BA
SHA-256 fingerprint
47:8E:A0:D5:67:3C:E9:57:5D:F1:D8:5E:35:B1:DC:D6:72:96:6E:05:4F:7E:80:2D:C3:07:5E:D0:B2:6E:68:7E
Chain
YR1 → Root YR → ISRG Root X1
Subject Alternative Names (2)
4comfort.cz, www.4comfort.cz

Certificate Authority Authorization (CAA)

The serving CA (Let's Encrypt) is authorized by this domain's CAA records (letsencrypt.org).

Never get surprised by 4comfort.cz's certificate expiring

This is today's certificate. Turn on monitoring and we'll watch 4comfort.cz 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.