semmle.net

We performed a comprehensive analysis of semmle.net on 2026-07-06. The website returned an HTTP 200 status code with a server response time of 14164ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 564 KB. Warning: The website does not have a valid SSL certificate. Visitors may see security warnings in their browser, and data transmitted to and from this website is not encrypted. The security headers analysis reveals a score of 85/100 (good). The following security headers are properly configured: Content-Security-Policy, Strict-Transport-Security (HSTS), X-Frame-Options, X-Content-Type-Options, and Referrer-Policy. However, the site is missing 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 semmle.net. The detected stack includes React. The UI is built with React. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, semmle.net receives an overall trust score of 73/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, semmle.net 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, HSTS (HTTP Strict Transport Security) enforcement preventing protocol downgrade attacks, SPF (Sender Policy Framework) email authentication preventing email spoofing, and DMARC email authentication with a none policy. Areas of concern include: 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 semmle.net 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 semmle.net 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. UI Library: React — handles the user interface rendering and component management for semmle.net.

semmle.net delivers its homepage in 14164ms (server response time), which is considered slow by industry standards. The total page weight is 564 KB, and we detected 282 resource requests loading assets from 31 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 34 CSS files and 0 out of 77 JavaScript files are minified. Minifying the remaining 111 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 semmle.net produces approximately 0.28g of CO₂, earning a carbon rating of C. This is an average carbon footprint. Optimizing images and reducing unnecessary scripts could further improve this score. For reference, the average web page produces about 0.5g of CO₂ per page view. The page weight of 564 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for semmle.net. 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.

semmle.net resolves to the IPv4 address 140.82.114.18, 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 4 name servers: dns1.p09.nsone.net, dns2.p09.nsone.net, dns3.p09.nsone.net, and dns4.p09.nsone.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 semmle.net 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 not enabled for semmle.net. 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 semmle.net contains 1,143 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 7 H2 headings, 14 H3 headings, 11 H4 headings. The page includes 4 images. 2 images (50%) 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 50% 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 38 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 77 external JavaScript files, 34 CSS stylesheets, and 0 iframes on the page. The site implements the following web standards and features: Progressive Web App (PWA) manifest (enabling app-like installation). Notable missing features: XML Sitemap, robots.txt, and Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility. We detected the following payment methods accepted on semmle.net: Discover. Offering multiple payment options including credit cards and digital wallets improves customer trust and can increase conversion rates. The website has social media presence across 5 platforms: Twitter (@github), Instagram (@github), Linkedin (@github), Tiktok (@github), and Github (@cmc_internal). An active social media presence is a positive trust indicator and helps build brand awareness and customer engagement.

The title tag for semmle.net is too long at 76 characters: "GitHub Advanced Security · Built-in protection for every repository · GitHub". At 76 characters, the title will likely be truncated in Google search results (recommended: 50-60 characters). Consider shortening it while keeping the most important keywords at the beginning. The meta description is 142 characters (well-optimized): "GitHub is where people build software. More than 150 million people use GitHub to discover, fork, and contribute to over...". 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://github.com/security/advanced-security, preventing duplicate content issues, the page language is declared as en, and a favicon is configured. Open Graph meta tags are configured with 4/4 recommended fields: OG title ("GitHub Advanced Security · Built-in protection for every rep..."), OG description, OG image (social sharing thumbnail), OG type (object). 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.