Website Uptime Monitor
Monitor website availability and server information for any domain
cat.or.jp
Uptime & Server Information
Current Status
Observed Changes
| Date | Status | Server |
|---|---|---|
| 6/6/2026, 6:57:35 AM | Active | nginx |
| 3/2/2026, 4:35:33 AM | Active | nginx |
Don't just check uptime once — watch it 24/7
This is a one-time check. Turn on monitoring and we'll watch the domains that matter to you 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.
About Website Uptime Monitoring
Use the Who.is uptime information to track the availability and server information of websites. This helps track:
- Website availability and response status
- Server software and configuration
- Meta information including titles and descriptions
- Historical uptime patterns
This information is valuable for website owners, system administrators, and anyone interested in monitoring website reliability and performance.
What this page reports
- Last status change: When we last saw a site switch between reachable and unreachable
- Last downtime: When a site was most recently seen down, and whether it has come back
- Server and meta information: The server software, page title and meta tags we last observed
We check a domain at most once a day and record an observation only when something changes, so these are the times a change was seen rather than the exact moment it happened. For continuous, minute-by-minute checks with alerting, use website monitoring.
Disclaimer: Who.is is not affiliated with, endorsed by, or connected to any of the domains displayed on this page. We provide this information as a public service for informational purposes only.