What powers challenge-zero.jp?
Last seen Oct 2026 · 16 technologies across 12 categories
Advertising
Twitter Ads
since Jul 2021
Analytics
Google Analytics
since May 2021
Authentication
Facebook Login
since Jul 2021
CDN
Cloudflare
since Mar 2025
Google Hosted Libraries
since Feb 2022
Font scripts
Google Font API
since Sep 2020
Hosting
Sakura Internet
since Sep 2022
JavaScript libraries
Miscellaneous
Open Graph
since Sep 2022
Programming languages
Java
since Sep 2021
Security
Cloudflare Bot Management
since Mar 2025
HSTS
since Sep 2022
Web servers
Apache HTTP Server
since Sep 2020
Widgets
Twitter
since Sep 2020
AI Crawlers
No robots.txt, so all AI crawlers are allowed by default. Checked Nov 2026.
- robots.txt not found
- llms.txt not found
- ai.txt not found
AI Crawlers
No robots.txt, all AI crawlers allowed
Audience
Japan
Where the site's Chrome visitors come from, largest estimated audience first.
Open Page Rank
4.65 / 10 · ranked #379,562 of all domains
55 referring domains · OpenPageRank
Search traffic
2 est. monthly organic visits (US)
33 keywords in Google's top 30
Core Web Vitals
| LCP | 2.6 s |
| INP | 50 ms |
| CLS | 0.05 |
| TTFB | 1300 ms |
Real user p75, Chrome UX Report, Oct 2026.
Page
- Language: Japanese
- Weight: 2.4 MB · 80 requests
- Structured data: OpenGraph
Homepage as crawled by the HTTP Archive, Oct 2026.
Infrastructure
- Hosted on Sakura Internet (153.127.12.234)
- DNS: Sakura Internet
- Email: no MX record returned
- Email security: SPF (hard fail), DMARC monitor only
- SSL: Let's Encrypt, ECDSA P256, expires Feb 2027
- Common Crawl link graph: rank 1,201,239, 2 hosts
DNS records as swept Nov 2026, certificate as seen Nov 2026. How the web is hosted
Full technology history →
Report an incorrect detection
Recent changes
- detected Cloudflare May 2026
- detected Cloudflare Bot Management May 2026
- dropped Pocket Apr 2026