SSL/TLS Certificate Lookup
Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted
a-ku.co.jp
SSL/TLS Certificate
SSL/TLS Certificate for a-ku.co.jp
Valid- Issued by (CA)
- Let's Encrypt
- Subject
- www.a-ku.co.jp
- Valid from
- Jul 20, 2026
- Valid until
- Oct 18, 2026 (45 days remaining)
- Public key
- RSA 2048-bit
- Serial
- 05295D535AEDBD6C950CA633EEB5EF08A1AF
- SHA-256 fingerprint
- BF:FE:5B:C3:21:9B:1C:01:D3:2C:C0:0B:E4:2A:EE:74:75:A2:B3:8F:0A:58:B9:F9:73:0D:2D:EC:EB:E2:E8:95
- 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.
This certificate has been served since Aug 31, 2026.
Never get surprised by a-ku.co.jp's certificate expiring
This is today's certificate. Turn on monitoring and we'll watch a-ku.co.jp 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.
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