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 a-ok.cz
Expiring soon- Issued by (CA)
- Let's Encrypt
- Subject
- a-ok.cz
- Valid from
- Jul 14, 2026
- Valid until
- Oct 12, 2026 (18 days remaining)
- Public key
- RSA 2048-bit
- Serial
- 056DD2C2DC44C785A48646B307EEC16DBD44
- SHA-256 fingerprint
- FD:5E:9C:51:45:F3:65:60:31:36:4E:EC:30:B6:02:DB:29:2E:C7:68:AA:04:BA:A1:91:0A:FA:F0:1D:69:40:22
- Chain
- YR2 → Root YR → ISRG Root X1
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 Jul 31, 2026.
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Uptime
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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.
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