What powers 
sisyfos.cz?
Last seen Oct 2026 · 14 technologies across 11 categories
Analytics
Authentication
CDN
JavaScript libraries
Marketing automation
Miscellaneous
Programming languages
Security
UI frameworks
Web frameworks
Web servers
AI Crawlers
Doesn't mention any of the 33 AI crawlers we track in its robots.txt; all are allowed by default. Checked Nov 2026.
- robots.txt found
- llms.txt not found
- ai.txt not found
AI Crawlers
No AI crawlers blocked
Audience
- 72% phone
- 28% desktop
Czechia
Slovakia
Where the site's Chrome visitors come from, largest estimated audience first.
Open Page Rank
4.58 / 10 · ranked #390,312 of all domains
121 referring domains · OpenPageRank
Core Web Vitals
| LCP | 1.3 s |
| INP | 50 ms |
| CLS | 1.2 |
| TTFB | 400 ms |
Real user p75, Chrome UX Report, Sep 2026.
Page
- Language: Czech
- Weight: 4.3 MB · 100 requests
- Structured data: JSON-LD, OpenGraph, Twitter Cards
Homepage as crawled by the HTTP Archive, Oct 2026.
Organisation
- Czech Skeptics' Club Sisyfos
- Founded: 1994
- Industry: Arts and entertainment (declares
Event) - Country: Czech Republic
From the homepage's own structured data (Oct 2026) and Wikidata (CC0).
Infrastructure
- Registered Jan 2002 (24 years) via Webglobe, s.r.o., renews Jan 2027
- Hosted on IGNUM-AS Webglobe, s.r.o. (217.31.57.146)
- DNS: rozhled.cz
- Email: sisyfos.cz
- Email security: SPF (soft fail), DMARC monitor only
- SSL: Let's Encrypt, RSA 4096, expires Dec 2026
- Common Crawl link graph: rank 752,567, 4 hosts
DNS records as swept Nov 2026, certificate as seen Nov 2026, registration from the registry's RDAP service. How the web is hosted