sudoku-online.org

We performed a comprehensive analysis of sudoku-online.org on 2026-06-30. The website returned an HTTP 200 status code with a server response time of 3838ms. The page is served over HTTP/1.1 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 74 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_256_GCM_SHA384 cipher suite and sha256WithRSAEncryption signature algorithm. The certificate covers 2 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 0/100 (poor). No security headers are configured, which is a significant security concern. However, the site is missing Content-Security-Policy, Strict-Transport-Security (HSTS), X-Frame-Options, 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 sudoku-online.org. The detected stack includes Google Analytics 4, Google Tag Manager, Google AdSense, reCAPTCHA v3, and Google Fonts. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, sudoku-online.org receives an overall trust score of 63/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, sudoku-online.org receives a trust score of 63/100, 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 80 days until expiration, and DMARC email authentication with a none policy. Areas of concern include: the absence of a Content-Security-Policy header, which leaves the site more vulnerable to cross-site scripting (XSS) attacks, no X-Frame-Options header, which could allow the site to be embedded in malicious iframes (clickjacking), missing Referrer-Policy, potentially leaking URL information to third parties, the domain's WHOIS information is hidden behind a privacy service, making it harder to verify the owner's identity, and DNSSEC is not enabled, leaving DNS queries vulnerable to spoofing attacks. While these issues don't necessarily indicate malicious intent, they represent areas where the website's security posture could be improved. We checked sudoku-online.org 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 sudoku-online.org 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. Analytics: Google Analytics 4 — tracks visitor behavior and provides traffic insights for sudoku-online.org. Tag Manager: Google Tag Manager — manages marketing and analytics tags without code changes for sudoku-online.org. Advertising: Google AdSense — handles advertising pixel tracking and conversion measurement for sudoku-online.org. Security: reCAPTCHA v3 — provides security features like bot detection and CAPTCHA for sudoku-online.org. Fonts: Google Fonts — delivers web fonts for typography for sudoku-online.org. We also extracted the following tracking identifiers: Google Analytics 4 Measurement ID G-QHBCSYW85V and Google Tag Manager container GTM-NBG2WS76. These IDs can be used to identify other websites operated by the same organization.

sudoku-online.org delivers its homepage in 3838ms (server response time), which is considered slow by industry standards. The total page weight is 74 KB, and we detected 213 resource requests loading assets from 13 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: 1 out of 1 CSS files and 1 out of 5 JavaScript files are minified. Minifying the remaining 4 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 sudoku-online.org produces approximately 0.04g 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 74 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for sudoku-online.org. 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.

sudoku-online.org resolves to the IPv4 address 159.65.203.183, but does not support IPv6. IPv6 adoption is increasingly important as IPv4 address space becomes exhausted, and some ISPs and regions are transitioning to IPv6-only connectivity. The domain has 1 A record(s) configured. The domain name system is managed by 3 name servers: ns1.digitalocean.com, ns2.digitalocean.com, and ns3.digitalocean.com. Having 3 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 sudoku-online.org is handled by Google Workspace with 6 MX records configured: aspmx.l.google.com, alt1.aspmx.l.google.com, and alt2.aspmx.l.google.com and 3 more. Multiple MX records provide failover redundancy — if the primary mail server is unavailable, email will be routed to the next available server. SPF is not configured, meaning any server could potentially send emails pretending to be from this domain. This is a significant email security concern. 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 not enabled for sudoku-online.org. While not critical for most websites, DNSSEC adds an important security layer by ensuring DNS responses haven't been tampered with during transit. Enabling DNSSEC is recommended for domains handling sensitive data or financial transactions.

The homepage of sudoku-online.org contains 1,081 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 6 H2 headings, 3 H3 headings, 3 H4 headings, 5 H5, and 0 H6 headings. The page includes 38 images. 1 images (3%) 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 97% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 142 internal links pointing to other pages on the same domain and 7 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 5 external JavaScript files, 1 CSS stylesheets, and 0 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), Schema.org structured data (AggregateRating, BreadcrumbList, ContactPoint, ImageObject, ListItem, Organization, PostalAddress, VideoGame, WebApplication, WebPage, and WebSite), Progressive Web App (PWA) manifest (enabling app-like installation), and RSS feed for content syndication. The website has social media presence across 2 platforms: Facebook (@sudokudiario) and Twitter (@sudokudiario). An active social media presence is a positive trust indicator and helps build brand awareness and customer engagement.

The title tag for sudoku-online.org is good at 27 characters: "Sudoku Online y Pasatiempos". The length is acceptable, though it may be slightly truncated in some search result displays. No meta description is configured for sudoku-online.org. This is a critical SEO oversight — without a meta description, Google will auto-generate a snippet from page content, which may not accurately represent the page or entice users to click. Adding a unique, compelling meta description of 120-155 characters is strongly recommended. The canonical url is correctly set to https://www.sudoku-online.org, preventing duplicate content issues, the page language is declared as es, and a favicon is configured. Open Graph meta tags are configured with 4/4 recommended fields: OG title ("Sudoku Online y Pasatiempos..."), 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. The site implements Schema.org structured data with the following types: AggregateRating, BreadcrumbList, ContactPoint, ImageObject, ListItem, Organization, PostalAddress, VideoGame, WebApplication, WebPage, and WebSite. Structured data helps search engines understand the page content and can enable rich results (featured snippets, knowledge panels, star ratings) in Google search results, which can significantly increase click-through rates.