What powers 
challenging.jp?
Last seen Oct 2026 · 15 technologies across 12 categories
Analytics
CMS
WordPress
since Jan 2025
Databases
MySQL
since Jan 2025
Font scripts
Google Font API
since Apr 2026
JavaScript libraries
Miscellaneous
RSS
since Jan 2025
Page builders
WordPress Block Editor
since Jan 2025
Performance
LazySizes
since Jan 2025
Programming languages
Web servers
Apache HTTP Server
since Jan 2016
Nginx
since Jan 2025
Webmail
Microsoft 365
since Oct 2022
WordPress plugins
WP-Optimize
since Jan 2025
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
- 100% desktop
Japan
Where the site's Chrome visitors come from, largest estimated audience first.
Open Page Rank
4.69 / 10 · ranked #356,432 of all domains
57 referring domains · OpenPageRank
Core Web Vitals
| LCP | 0.3 s |
| INP | 25 ms |
| CLS | 0 |
| TTFB | 100 ms |
Real user p75, Chrome UX Report, Oct 2026.
Page
- Language: Japanese
- Weight: 1.7 MB · 66 requests
Homepage as crawled by the HTTP Archive, Oct 2026.
Infrastructure
- Hosted on BBTower - BroadBand Tower, Inc. (211.14.31.161)
- DNS: bbtower.ne.jp
- Email: Microsoft 365
- Email security: SPF (soft fail), DMARC monitor only
- Common Crawl link graph: rank 11,537,094, 5 hosts
- Verified with: Microsoft 365
DNS records as swept Nov 2026. How the web is hosted
Subdomains
| Host | Techs |
|---|---|
| blog.challenging.jp | 12 |
| www.challenging.jp | 6 |
| ad.challenging.jp | 5 |