zsplavani.cz

We performed a comprehensive analysis of zsplavani.cz on 2026-07-05. The website returned an HTTP 200 status code with a server response time of 7056ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 35 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 1.3 with the TLS_AES_128_GCM_SHA256 cipher suite and ECDSA-SHA384 signature algorithm. The certificate covers 1 domain(s) (Subject Alternative Names) and expires on 2026-08-10, which is 36 days from now. The security headers analysis reveals a score of 45/100 (below average). The following security headers are properly configured: X-Frame-Options, X-Content-Type-Options, and Referrer-Policy. However, the site is missing Content-Security-Policy, Strict-Transport-Security (HSTS), and Permissions-Policy, which could expose the site and its users to cross-site scripting (XSS), clickjacking, and other web-based attacks. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, zsplavani.cz receives an overall trust score of 73/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, zsplavani.cz receives a trust score of 73/100, 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, a valid SSL certificate issued by Let's Encrypt with 36 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: the absence of a Content-Security-Policy header, which leaves the site more vulnerable to cross-site scripting (XSS) attacks 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 zsplavani.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 automated technology detection scan was unable to identify specific technologies on zsplavani.cz. This could indicate that the site uses server-side rendering without client-side technology fingerprints, employs aggressive code obfuscation, or uses custom-built solutions that don't match known technology signatures.

zsplavani.cz delivers its homepage in 7056ms (server response time), which is considered slow by industry standards. The total page weight is 35 KB, and we detected 56 resource requests loading assets from 8 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 1 CSS files and 0 out of 1 JavaScript files are minified. Minifying the remaining 2 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 zsplavani.cz produces approximately 0.02g 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 35 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for zsplavani.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.

zsplavani.cz resolves to the IPv4 address 80.211.209.211 and also supports IPv6 (2001:15e8:110:50d3::1), demonstrating modern network infrastructure readiness. The domain has 1 A record(s) configured. The domain name system is managed by 4 name servers: ns.wedos.com, ns.wedos.cz, ns.wedos.eu, and ns.wedos.net. Having 4 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 zsplavani.cz is handled by wedos.net with 3 MX records configured: wes1-mx1.wedos.net, wes1-mx2.wedos.net, and wes1-mx-backup.wedos.net. 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 zsplavani.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 zsplavani.cz contains 580 words of visible text content. This is a moderate amount of content. The page is structured with 2 H2 headings, 11 H3 headings, 0 H4 headings. The page includes 11 images. 11 images (100%) 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 0% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 32 internal links pointing to other pages on the same domain and 9 external links pointing to third-party websites. There are 1 external JavaScript files, 1 CSS stylesheets, and 0 iframes on the page. Notable missing features: XML Sitemap, robots.txt, and Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility. The website has social media presence across 3 platforms: Facebook (@zsprodeti), Instagram (@zsprodeti), and Youtube (@zsprodeti5929). An active social media presence is a positive trust indicator and helps build brand awareness and customer engagement.

The title tag for zsplavani.cz is good at 18 characters: "Naše kurzy plavání". The length is acceptable, though it may be slightly truncated in some search result displays. The meta description is 200 characters (slightly long): "ZŠ PLAVÁNÍ spojuje plaveckou výuku, školu v přírodě, sportovní a zábavní program. Děti absolvují deset devadesátiminutov...". 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://zsprodeti.cz/plavani/kurzy, preventing duplicate content issues, the page language is declared as cs, and a favicon is configured. Open Graph meta tags are configured with 4/4 recommended fields: OG title ("Naše kurzy plavání..."), OG description, OG image (social sharing thumbnail), OG type (website). These tags control how the page appears when shared on Facebook, LinkedIn, and other social media platforms that support the Open Graph protocol.