SEO Render Diff: Initial vs Rendered DOM

Compare the HTML the server sends with the DOM after JavaScript, and see which SEO elements only exist once the page renders.

See what JavaScript changes on any page, and what search engines and AI crawlers get before it runs. SEO Render Diff compares the initial DOM (the HTML the server sends) with the rendered DOM (the page after JavaScript runs), side by side, with the differences highlighted: green for what JavaScript adds, red for what it removes. THREE VIEWS, SIDE BY SIDE • Initial DOM, Rendered DOM and Difference, formatted and syntax highlighted. • Find and filter in one view or in all three at once, with match counter and previous/next. • "Only show this" focuses one view and folds the others into side tabs. • Copy or download each view; download the changes as CSV. PREVIEW WITHOUT JAVASCRIPT • Switch the initial DOM to Preview and see the page as a crawler that does not render sees it: scripts off, <noscript> content on. • Put it next to the rendered preview and the missing content is obvious at a glance. SEO SIGNALS • The main on-page SEO elements (title, meta tags, canonical, headings, structured data, links and more) in the initial and the rendered DOM, with a status for each one: same, changed by JS, only after JS, removed by JS. • Links that only exist after JavaScript. • JS dependency: the share of the rendered text that only exists after JavaScript runs, in red above 50%. • Download everything as CSV. ROBOTS.TXT ACCESS PER BOT • Reads the site's robots.txt and evaluates it with Google's matching rules for the main search engine and AI crawlers. • Shows whether each bot may crawl the URL, and the exact rule and line that decide it. BROWSER VS BOT • Fetch the initial DOM as a search engine or AI crawler and compare it with what your browser received, HTTP status included. • Catches dynamic rendering, cloaking and firewalls that block AI crawlers with a 403. PRIVATE BY DESIGN • All the analysis runs in your browser. Nothing is sent to any server. • No account, no tracking, no analytics. • Asks for access to a site only when you fetch it as a bot, one site at a time. English and Spanish interface. Made by Cristobal Cazor, technical SEO consultant: https://cristobalcazor.com