vnoi.info

We performed a comprehensive analysis of vnoi.info on 2026-06-30. The website returned an HTTP 200 status code with a server response time of 26242ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 90 KB, and the site is served behind a CDN (Content Delivery Network). The website uses a secure HTTPS connection with a valid SSL certificate issued by Google Trust Services (DV type). The connection is encrypted using TLS 1.3 with the TLS_AES_256_GCM_SHA384 cipher suite and ECDSA-SHA256 signature algorithm. The certificate covers 2 domain(s) (Subject Alternative Names) and expires on 2026-08-09, which is 40 days from now. The security headers analysis reveals a score of 15/100 (poor). The following security headers are properly configured: X-Frame-Options. However, the site is missing Content-Security-Policy, Strict-Transport-Security (HSTS), 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 1 technologies across 1 categories powering vnoi.info. The detected stack includes Google Analytics 4. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, vnoi.info receives an overall trust score of 63/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, vnoi.info 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 Google Trust Services with 40 days until expiration, and SPF (Sender Policy Framework) email authentication preventing email spoofing. Areas of concern include: the absence of a Content-Security-Policy header, which leaves the site more vulnerable to cross-site scripting (XSS) attacks, 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 vnoi.info 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 vnoi.info and identified 1 distinct technologies across 1 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 vnoi.info. We also extracted the following tracking identifiers: Google Analytics 4 Measurement ID G-YXGZG6XL9E. These IDs can be used to identify other websites operated by the same organization.

vnoi.info delivers its homepage in 26242ms (server response time), which is considered slow by industry standards. The total page weight is 90 KB, and we detected 266 resource requests loading assets from 10 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 3 CSS files and 2 out of 7 JavaScript files are minified. Minifying the remaining 8 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. The site is served through a Content Delivery Network (CDN), which caches static assets at edge servers around the world. This means visitors from different geographic regions receive content from the nearest edge server, significantly reducing latency. CDN usage is particularly important for websites with a global audience, as it can reduce page load times by 40-60% for distant visitors. From an environmental perspective, each page view of vnoi.info 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 90 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for vnoi.info. 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.

vnoi.info resolves to the IPv4 address 172.67.137.217 and also supports IPv6 (2606:4700:3037::ac43:89d9), demonstrating modern network infrastructure readiness. The domain has 2 A record(s) configured. The domain name system is managed by 2 name servers: tosana.ns.cloudflare.com and ulla.ns.cloudflare.com. 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 vnoi.info is handled by Google Workspace with 6 MX records configured: alt1.aspmx.l.google.com, alt2.aspmx.l.google.com, and alt3.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 (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 is not configured, leaving the domain vulnerable to email spoofing and phishing attacks that impersonate this domain. 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 vnoi.info. 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 vnoi.info contains 5,517 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 10 H2 headings, 14 H3 headings, 13 H4 headings, 5 H5, and 0 H6 headings. The page includes 41 images. 39 images (95%) 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 5% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 140 internal links pointing to other pages on the same domain and 34 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 7 external JavaScript files, 3 CSS stylesheets, and 0 iframes on the page. The site implements the following web standards and features: Schema.org structured data (SearchAction and WebSite), Progressive Web App (PWA) manifest (enabling app-like installation), and RSS feed for content syndication. Notable missing features: XML Sitemap and robots.txt. Adding these could improve search engine discoverability and rich result eligibility. The website has social media presence across 2 platforms: Facebook (@vnoi.wiki) and Github (@VNOI-Admin). An active social media presence is a positive trust indicator and helps build brand awareness and customer engagement.

The title tag for vnoi.info is well-optimized at 35 characters: "Trang chủ - VNOJ: VNOI Online Judge". The length falls within the ideal range for Google search results, ensuring the full title is displayed without truncation. The meta description is 40 characters (acceptable): "VNOJ - Online Judge chính thức của VNOI.". 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://oj.vnoi.info/, preventing duplicate content issues, the page language is declared as vi, and a favicon is configured. Open Graph meta tags are configured with 2/4 recommended fields: OG description, OG image (social sharing thumbnail), 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: SearchAction 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. The meta keywords tag contains 14 terms including VNOJ, VOI, VNOI, HSG, and HSG tin học. Note: Google has officially confirmed that it does not use the meta keywords tag as a ranking signal. However, some other search engines (Bing, Yandex) may still reference it.