SEO Institute HTML Checker

Multilingual HTML, SEO, link, security, technology, and AI protocol checker.

SEO Institute HTML Checker is a browser extension designed to inspect the HTML structure and technical SEO settings of your current webpage. Simply select the categories you want to inspect, configure your request delay and link-checking scope, and initiate the analysis. The tool provides real-time progress updates and organizes findings into intuitive statuses: Passed, Failed, Found, or Not Found. Key Capabilities : (1)Core Technical Analysis: Analyze HTTP response codes, verify HTTPS usage, and smoothly detect broken links, soft 404 pages, and mixed content issues. (2)Structure & Directives: Validate essential document structures (HTML, HEAD, BODY), language declarations, and viewport settings. The tool thoroughly inspects crawling directives including Meta Robots, X-Robots-Tag, canonical URLs, alternate links, and hreflang implementations. (3)Content & Metadata: Evaluate on-page elements such as page titles, meta descriptions, H1–H6 heading hierarchies, and image ALT attributes. It also identifies social sharing metadata (Open Graph and Twitter Cards) alongside XML Sitemaps and RSS/Atom feeds. (4)Structured Data & Tech Stack: Automatically detect Schema.org configurations (JSON-LD, Microdata, RDFa), identify common CMS platforms or frontend frameworks, and verify active tracking integrations like Google Analytics 4, Tag Manager, Search Console, and Bing Webmaster Tools. (5)AI Protocol Integration: Check for modern AI web protocols and configuration standards. The extension seamlessly detects UCP, WebMCP, and various large language model text configuration formats (including standard, full, and context-specific LLM files). (6)Data Export: Instantly export your complete audit results into a well-formatted UTF-8 Markdown report. Global Localization : Built for a worldwide audience, the user interface natively adapts to several major languages. Users can navigate comfortably in English, access European localizations like French, Spanish, or German, and utilize comprehensive Asian language support covering Japanese as well as both Traditional and Simplified Chinese. Privacy & Operation : The extension strictly inspects only the webpage currently selected by the user, and no page content is permanently stored. Inspection progress and results are temporarily preserved while operating within the same browser tab, ensuring a seamless experience even if the popup is temporarily closed. Switching tabs will automatically clear these temporary results. Note: Certain advanced features—such as soft 404, CMS, frontend framework, and tracking-code detection—rely on visible technical signals and may require manual verification.