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 koeln.de
Valid- Issued by (CA)
- Asseco Data Systems S.A.
- Subject
- *.koeln.de
- Valid from
- Mar 4, 2026
- Valid until
- Apr 3, 2027 (256 days remaining)
- Public key
- RSA 4096-bit
- Serial
- 642676192C74014BFCE227DA3960F36B
- SHA-256 fingerprint
- CE:40:E5:72:B4:32:14:AE:90:E4:F3:66:AA:EB:04:A4:F2:F2:9D:67:86:40:B0:D7:76:34:3F:3B:74:AB:DE:89
- Chain
- Certum DV TLS G2 R39 CA → Certum Trusted Root CA
Certificate Authority Authorization (CAA)
No CAA policy is published for this domain — any certificate authority may issue for it.