How Each Major CMS Reveals Itself
Hosted platforms are the easiest to detect because their assets are always served from a fixed, platform-owned domain. Shopify assets load from cdn.shopify.com regardless of the store's own domain. Webflow assets load from uploads-ssl.webflow.com or assets.website-files.com. Squarespace assets load from static1.squarespace.com. Wix assets load from static.wixstatic.com. None of these domains change based on which store or site is using the platform, which makes them close to deterministic detection signals.
Self-hosted platforms like WordPress and Drupal are detected differently, since assets are served from the site's own domain rather than a platform-owned CDN. WordPress is identified by its wp-content/ and wp-includes/ directory structure appearing in asset paths, plus a generator meta tag when not removed for security hardening. Drupal is identified by its sites/default/files/ asset path structure and Drupal-specific JavaScript settings object.
What Happens When a Site Doesn't Match Any Known CMS
Not every website runs on a recognizable CMS. Custom-built sites using a framework like Next.js, Ruby on Rails, or a hand-coded static site have no CMS to detect — the result in this case correctly shows no CMS match rather than forcing an incorrect guess. This is a common and expected result for sites built by development agencies or in-house engineering teams rather than on a packaged content platform.
Headless CMS setups are a middle case — the content management system (Contentful, Sanity, Strapi) exists, but it doesn't render the front-end directly, so the public-facing site shows the front-end framework (often Next.js or Gatsby) rather than the headless CMS itself, since the CMS's signature isn't present in what the browser receives.