Undersite: Tech Stack, SEO & Hosting Checker

See what any site is built with: CMS, plugins, AI builders, tracking tags, SEO, AI crawlers, hosting and DNS. Private by design.

Undersite shows you what's under any website, right in Chrome's side panel. Open a site, click the Undersite icon, and you get a clear breakdown in a couple of seconds. The first card answers the questions most people open a tool like this for: what platform the site runs on, what it was built with, where it is hosted and what powers the front end. WHAT YOU GET - The platform or CMS behind the site, including popular AI website builders, with a clear note when a site was built with AI - A WordPress deep dive: core version, active theme and the plugins loading on the page, with an optional check that flags outdated plugins - Page builders, JavaScript frameworks and libraries, with versions where the page exposes them - Analytics, ad and marketing tags, with each tracking ID ready to copy - Live chat and AI assistant widgets - Hosting company, IP address, CDN, DNS provider, email provider and the raw DNS records SEO AND AI SEARCH - An on-page SEO score that explains every point it takes off - A site-wide view of robots.txt and the sitemap, with published pages grouped by type and every URL one click from your clipboard - AI search visibility: which AI crawlers the site allows or blocks, and whether it publishes an llms.txt file Every result shows how confident Undersite is and the exact evidence behind it, so you can judge it for yourself. You can export any scan as a text file or a printable PDF report. PRIVATE BY DESIGN - No account, no sign-up, no analytics, no tracking - Scans run in your browser, and nothing about you is sent anywhere - Results live in session memory and disappear when Chrome closes - Undersite can't see a tab until you click its icon there Made by Sukesh Das, a freelance web developer who checks site stacks every day and wanted a tool that is fast, honest about what it can and cannot see, and respectful of your privacy.