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 on-u.jp
Valid- Issued by (CA)
- Let's Encrypt
- Subject
- www.on-u.jp
- Valid from
- Jun 5, 2026
- Valid until
- Sep 3, 2026 (32 days remaining)
- Public key
- RSA 2048-bit
- Serial
- 06520BC6D5DB30875239BC7EB1EAC75EB8A1
- SHA-256 fingerprint
- 65:04:71:DB:56:32:33:05:0D:BA:13:2C:67:68:36:B3:FB:E5:93:5A:69:99:63:A4:78:16:C3:05:1C:DA:84:09
- 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 on-u.jp's certificate expiring
This is today's certificate. Turn on monitoring and we'll watch on-u.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.
Free for your first domain: uptime, DNS, and certificate together. No credit card.