Website tech stack checker

See what any website is built with. Enter a URL and we detect the CMS, JavaScript framework, ecommerce platform, analytics, hosting and CDN from its public code and response headers.

How it works

  • We fetch the page's public HTML and response headers and match them against a curated table of fingerprints: script and stylesheet URLs, the generator meta tag, cookies, and headers like server and x-powered-by.
  • Each signature is deliberately specific, for example wp-content/ for WordPress or /_next/static/ for Next.js, so a technology is only reported when a clear marker is genuinely present in the page source.
  • The table covers CMS platforms, ecommerce systems, JavaScript frameworks and libraries, CSS frameworks, analytics and tag managers, marketing and support widgets, plus hosting, CDN and web server signals from the response headers.
  • It only sees what any visitor's browser sees on the initial load, with no JavaScript executed, so heavily server-rendered, proxied, or interaction-only sites may reveal less. Nothing is stored.

What to do with the results

  • Sizing up a competitor before you build against them. Their CMS and ecommerce platform hint at how fast they can ship changes, and their analytics and marketing tags show which channels they invest in.
  • Spotting a replatform early. A shift from WooCommerce to Shopify, or a new tag manager appearing, usually precedes a bigger commercial move, like a new pricing page or checkout flow.
  • Auditing your own site. Confirm old analytics snippets or unused libraries have actually been removed after a migration, rather than assuming the deploy cleaned everything up.
  • Nothing detected doesn't mean nothing is there. Try another page on the same site; a heavily optimised home page often exposes fewer markers than a product or blog page.

A single check only shows the stack right now. For ongoing competitor monitoring that alerts you the moment a rival changes their platform, tags, or code, SiteGauge can watch their pages on a schedule and show you a before/after diff.

Frequently asked questions

It fetches the page's public HTML and response headers, then matches them against a curated table of fingerprints: script and stylesheet URLs, the generator meta tag, cookies, and headers like server and x-powered-by. Each signature is deliberately specific, for example wp-content/ paths for WordPress or /_next/static/ for Next.js, so a technology is only reported when a clear marker is actually present in the page source.

The fingerprint table covers CMS platforms (WordPress, Drupal, Webflow, Wix, Squarespace, Ghost and others), ecommerce systems (Shopify, WooCommerce, Magento, BigCommerce), JavaScript frameworks and libraries (Next.js, Nuxt, React, Vue, Angular, Svelte, Astro, jQuery), CSS frameworks, analytics and tag managers, marketing and support widgets, plus hosting, CDN and web server signals taken from response headers.

This checker reads one page's HTML and headers without executing JavaScript or crawling the rest of the site, and it only claims a match on a reasonably specific marker. Browser extensions can watch live network traffic and inspect the rendered DOM, so they surface more, including some guesses. The trade-off here is confidence: everything listed was genuinely found in the page the server sent.

Some sites render entirely on the server and ship HTML with no framework markers, strip identifying headers at a proxy or CDN, or load their JavaScript only after interaction. If the marker never appears in the initial HTML or headers, the tool cannot see it. Try another page on the same site; product, blog or app pages often expose more than a heavily optimised home page.

Re-run the check periodically and compare, or automate it. A replatform, say WooCommerce to Shopify, or a new analytics and A/B testing tag is exactly the kind of early signal worth catching, because it usually precedes bigger commercial changes. SiteGauge can watch competitor pages on a schedule and alert you when their code or content changes, with a before/after diff, so stack drift gets noticed without manual re-checking.