lupa.cz

We performed a comprehensive analysis of lupa.cz on 2026-06-30. The website returned an HTTP 200 status code with a server response time of 37133ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 290 KB. The website uses a secure HTTPS connection with a valid SSL certificate issued by Let's Encrypt (DV type). The connection is encrypted using TLS 1.2 with the ECDHE-RSA-AES256-GCM-SHA384 cipher suite and sha256WithRSAEncryption signature algorithm. The certificate covers 12 domain(s) (Subject Alternative Names) and expires on 2026-09-18, which is 80 days from now. The security headers analysis reveals a score of 55/100 (moderate). The following security headers are properly configured: Content-Security-Policy, Strict-Transport-Security (HSTS), and X-Frame-Options. However, the site is missing X-Content-Type-Options, Referrer-Policy, and Permissions-Policy, which could expose the site and its users to cross-site scripting (XSS), clickjacking, and other web-based attacks. Our technology detection scan identified 5 technologies across 5 categories powering lupa.cz. The detected stack includes React, Google Tag Manager, Google AdSense, Google Fonts, and jQuery. The UI is built with React. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, lupa.cz receives an overall trust score of 77/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, lupa.cz receives a trust score of 77/100, which places it in the "Likely Safe" category. This score is calculated by evaluating multiple factors including SSL certificate validity, domain registration history, email authentication protocols, security header configuration, and blacklist status across major threat intelligence databases. The analysis identified several positive trust signals: a valid HTTPS connection protecting data in transit, HSTS (HTTP Strict Transport Security) enforcement preventing protocol downgrade attacks, a valid SSL certificate issued by Let's Encrypt with 80 days until expiration, SPF (Sender Policy Framework) email authentication preventing email spoofing, DMARC email authentication with a none policy, and DNSSEC providing authenticated DNS responses. Areas of concern include: missing Referrer-Policy, potentially leaking URL information to third parties and the domain's WHOIS information is hidden behind a privacy service, making it harder to verify the owner's identity. While these issues don't necessarily indicate malicious intent, they represent areas where the website's security posture could be improved. We checked lupa.cz against 8 major blacklist databases including Google Safe Browsing, Phishtank, Urlhaus, Openphish, Dnsfilter, Spamhaus Dbl, Surbl, and Virustotal. The domain passed all 8 checks with a clean status, meaning it has not been flagged for phishing, malware distribution, spam, or other malicious activities by any of the tested threat intelligence providers.

Our technology detection engine scanned lupa.cz and identified 5 distinct technologies across 5 categories. This analysis is performed by examining HTTP response headers, HTML source code patterns, JavaScript library fingerprints, CSS framework signatures, and DNS records. UI Library: React — handles the user interface rendering and component management for lupa.cz. Tag Manager: Google Tag Manager — manages marketing and analytics tags without code changes for lupa.cz. Advertising: Google AdSense — handles advertising pixel tracking and conversion measurement for lupa.cz. Fonts: Google Fonts — delivers web fonts for typography for lupa.cz. JavaScript Library: jQuery — provides utility functions and DOM manipulation for lupa.cz. We also extracted the following tracking identifiers: Google Tag Manager container GTM-P6PN6D. These IDs can be used to identify other websites operated by the same organization.

lupa.cz delivers its homepage in 37133ms (server response time), which is considered slow by industry standards. The total page weight is 290 KB, and we detected 176 resource requests loading assets from 7 third-party domains. A high number of third-party domains can significantly impact page load time due to additional DNS lookups and TLS handshakes required for each domain. The website uses Gzip compression for text-based assets, achieving an estimated 60.0% reduction in transfer size. This reduces bandwidth usage and improves page load times, especially for visitors on slower connections. Asset minification status: 0 out of 0 CSS files and 0 out of 13 JavaScript files are minified. Minifying the remaining 13 unminified file(s) could further reduce page weight by 10-30% for those assets. Minification is a best practice that reduces download sizes without affecting functionality. From an environmental perspective, each page view of lupa.cz produces approximately 0.14g of CO₂, earning a carbon rating of A. This places the website among the cleanest on the web, demonstrating efficient use of server resources and optimized content delivery. For reference, the average web page produces about 0.5g of CO₂ per page view. The page weight of 290 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for lupa.cz. This typically means the site doesn't have enough real-world Chrome user traffic to generate statistically significant field data, or the domain is not included in the CrUX dataset. Core Web Vitals (LCP, INP, CLS) are important Google ranking factors that measure real user experience.

lupa.cz resolves to the IPv4 address 91.213.160.123 and also supports IPv6 (2001:67c:68::7b), demonstrating modern network infrastructure readiness. The domain has 1 A record(s) configured. The domain name system is managed by 2 name servers: ns.iinfo.cz and ns6.adminit.cz. Having 2 name servers provides good redundancy — if one fails, the others can continue serving DNS queries. The choice of name servers often indicates the DNS hosting provider or CDN service being used. Email for lupa.cz is handled by Google Workspace with 5 MX records configured: ASPMX.L.GOOGLE.COM, ALT1.ASPMX.L.GOOGLE.COM, and ALT2.ASPMX.L.GOOGLE.COM and 2 more. Multiple MX records provide failover redundancy — if the primary mail server is unavailable, email will be routed to the next available server. SPF (Sender Policy Framework) is configured, which specifies which mail servers are authorized to send email on behalf of this domain. This helps prevent email spoofing and improves email deliverability. DMARC (Domain-based Message Authentication, Reporting and Conformance) is configured with a none policy — a monitoring-only setting that doesn't enforce any action on unauthorized emails. DKIM was not detected. Without DKIM, recipients cannot cryptographically verify that emails claiming to be from this domain are authentic. DNSSEC is enabled for lupa.cz, providing an additional layer of security by cryptographically signing DNS records. This prevents DNS cache poisoning and man-in-the-middle attacks that could redirect visitors to malicious websites.

The homepage of lupa.cz contains 1,402 words of visible text content. This is a substantial amount of content that provides good opportunities for search engine indexing. The page is structured with 5 H2 headings, 35 H3 headings, 0 H4 headings. The page includes 23 images. 2 images (9%) are missing alt text attributes, which is a significant concern for both accessibility and SEO. Screen readers rely on alt text to describe images to visually impaired users, and search engines use alt text to understand image content. Only 91% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 112 internal links pointing to other pages on the same domain and 2 external links pointing to third-party websites. The high number of internal links suggests a well-interconnected site structure, which helps search engines discover and crawl all pages efficiently. There are 13 external JavaScript files, 0 CSS stylesheets, and 2 iframes on the page. The site implements the following web standards and features: XML Sitemap (helps search engines discover all pages), robots.txt (controls search engine crawling behavior), Progressive Web App (PWA) manifest (enabling app-like installation), and RSS feed for content syndication. Notable missing features: Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility.

The title tag for lupa.cz is well-optimized at 35 characters: "Lupa.cz - server o českém Internetu". The length falls within the ideal range for Google search results, ensuring the full title is displayed without truncation. The meta description is 129 characters (well-optimized): "Svět IT, dění na trhu, bezpečnost na internetu, připojení k internetu, mobilní internet, online média a reklama, cloudov...". Google typically displays up to 155-160 characters of the meta description in search results. A compelling meta description with a clear call-to-action can significantly improve click-through rates from search results. The canonical url is correctly set to https://www.lupa.cz/, preventing duplicate content issues, the page language is declared as cs, the meta robots directive is set to index, follow, max-image-preview:large, and a favicon is configured. Open Graph meta tags are configured with 4/4 recommended fields: OG title ("Lupa.cz - server o českém Internetu..."), OG description, OG image (social sharing thumbnail), OG type (article). These tags control how the page appears when shared on Facebook, LinkedIn, and other social media platforms that support the Open Graph protocol. A Twitter Card of type summary_large_image is configured, which controls how links appear when shared on Twitter/X. The "summary_large_image" type displays a large image preview, which typically generates higher engagement rates than the basic card type.