What powers f21.vn?
Last seen Aug 2026 · 16 technologies across 10 categories
Analytics
Ecommerce
Bizweb
since Jul 2026
Cart Functionality
since Jul 2026
JavaScript frameworks
JavaScript libraries
FingerprintJS
since Jul 2026
Swiper
since Jul 2026
Miscellaneous
Open Graph
since Jul 2026
Programming languages
Sass
since Jul 2026
Security
HSTS
since Jul 2026
Tag managers
Google Tag Manager
since Jul 2026
Video players
YouTube
since Jul 2026
Web servers
Nginx
since Jul 2026
AI Crawlers
Doesn't name any of the 33 AI crawlers we track in its robots.txt. Catch-all rules (User-agent: *) restrict some paths for every crawler, AI or not. Checked Aug 2026.
- robots.txt found
- llms.txt not checked
- ai.txt not checked
AI Crawlers
No AI crawlers blocked
Audience
- 76% phone
- 17% desktop
- 7% tablet
Vietnam
Where the site's Chrome visitors come from, largest estimated audience first.
Open Page Rank
0.47 / 10 · ranked #27,147,051 of all domains
1 referring domains · OpenPageRank
Core Web Vitals
| LCP | 3.1 s |
| CLS | 0 |
| TTFB | 1000 ms |
Real user p75, Chrome UX Report, Aug 2026.
Page
- Language: Vietnamese
- Weight: 9.6 MB · 132 requests
- Structured data: OpenGraph
Homepage as crawled by the HTTP Archive, Aug 2026.