Website CMS Detector - What CMS Is That Site?

Website CMS Detector tells you what a website is built with, and shows you why. Open any site and click the toolbar icon. The extension reports the content management system powering the page, how confident it is, and the version when the page exposes one. Instead of a black-box guess, every verdict comes with an evidence chain you can check yourself. WHAT IT DOES • Identifies the platform behind the page you are viewing, with a confidence level and version information when available. • Shows a verifiable evidence chain: each conclusion lists the observations behind it, such as the matched snippet from the page, a response header, a hostname rule, or the HTTP status of a verification probe. • Covers more than 160 self-hosted, hosted and headless systems, including website builders and e-commerce platforms. • Provides a WordPress deep dive, identifying the active theme with its version and author, along with installed plugins resolved from asset paths, inline signatures and the REST API. • Screens the page for adult content in a separate pass, which is useful for brand safety checks and compliance review. • Warns you when two platforms score close together, instead of handing you a confident wrong answer. PRIVATE BY DESIGN Detection runs entirely in your browser. There is no account, no sign-in and no tracking, and page content never leaves your machine. Reporting of detected sites is off by default and only starts if you explicitly choose Allow; even then it sends only the site URL, never page content or your results. HOW TO USE IT 1. Browse to any website. 2. Click the extension icon. The badge shows CMS when a platform is identified, ? when the match is uncertain, and 18+ for adult content. 3. Open the popup for the full evidence chain, candidate list and confidence levels. 4. Choose Deep verify to run a small set of verification probes and to resolve the active theme and installed plugins. GOOD TO KNOW • Deep verify sends a few probe requests to the target site from your own IP address. It never runs automatically. • Response headers may be unavailable for pages served from cache or pre-rendered, which can remove a few evidence items but rarely changes the verdict. • Very large pages are analyzed up to 2.5 MB of HTML. • Site counts, historical records and directory pages live on our website, not in the extension. WHO IT IS FOR Developers auditing a stack, SEO and marketing teams researching competitors, agencies qualifying leads, security analysts doing reconnaissance, and anyone who has ever wondered what a website is built with. PERMISSIONS, AND WHY • webRequest: reads the response headers of the page you are on. It is read-only, nothing is blocked or modified. • storage: remembers your settings and the current tab result. • tabs: shows the result for the tab you are viewing. • Access to all sites: required, because you can inspect any website you visit. ABOUT THE ENGINE The detection engine and fingerprint library are generated from the same source as our server side detector, so the extension and the website give you the same answer. If a site is detected incorrectly, tell us: the evidence chain makes it easy to show exactly what went wrong and to fix it fast.