What powers 21b.app?
Last seen Jul 2026 · 19 technologies across 13 categories
CDN
CMS
Ecommerce
IaaS
Issue trackers
JavaScript frameworks
JavaScript libraries
Miscellaneous
PaaS
Performance
Security
UI frameworks
AI Crawlers
Blocks 1 of 33 AI crawlers we track by name in its robots.txt. Checked Sep 2026.
Search and AI assistants
- PetalBot Blocked
The other 32 AI crawlers we track are not mentioned and only inherit the catch-all rules that apply to every crawler.
- robots.txt found
- llms.txt found
- ai.txt not checked
AI Crawlers
1 of 33 AI crawlers blocked
Standards: llms.txt
Audience
- 100% desktop
United States
Where the site's Chrome visitors come from, largest estimated audience first.
Open Page Rank
1.44 / 10 · ranked #7,032,392 of all domains
3 referring domains · OpenPageRank
Search traffic
13 est. monthly organic visits (US)
23 keywords in Google's top 30
Core Web Vitals
| LCP | 1.4 s |
| CLS | 0 |
| TTFB | 500 ms |
Real user p75, Chrome UX Report, Sep 2026.
Infrastructure
- Email: Google Workspace
- Email security: no SPF record, no DMARC record, DNSSEC signed
- SSL: Let's Encrypt, RSA 2048, expires Oct 2026
- Common Crawl link graph: rank 8,193,579, 2 hosts
DNS records as swept Sep 2026, certificate as seen Sep 2026. How the web is hosted