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-u.de
Valid- Issued by (CA)
- Let's Encrypt
- Subject
- a-u.de
- Valid from
- Jun 24, 2026
- Valid until
- Sep 22, 2026 (55 days remaining)
- Public key
- RSA 4096-bit
- Serial
- 05C63EDCAC02B9546C0B2B93FD1B7B4DFC60
- SHA-256 fingerprint
- 89:8F:EF:3E:BC:39:A8:A7:06:05:A8:BF:4B:B4:1E:EF:4F:2A:42:A1:31:B3:54:6D:E7:91:C5:AC:34:3C:DD:69
- Chain
- YR1 → Root YR → ISRG Root X1
Certificate Authority Authorization (CAA)
No CAA policy is published for this domain — any certificate authority may issue for it.
Never get surprised by a-u.de's certificate expiring
This is today's certificate. Turn on monitoring and we'll watch a-u.de 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.
Free for your first domain: uptime, DNS, and certificate together. No credit card.