Tech Stack Checker: Detect the CMS, Framework, and Tools Behind Any Site
Paste any URL and RankNibbler identifies the content management system, JavaScript framework, analytics tools, CDN, CSS framework, and 40+ other technologies powering the site. Free, instant, no signup. Use it for competitor research, sales qualification, or technical due diligence.
What Is a Tech Stack?
A tech stack is the collection of software technologies a website uses to run. On the front end, that typically means a CMS or static site generator, a JavaScript framework, a CSS framework, and third-party integrations. On the back end, it includes hosting infrastructure, CDN, analytics, marketing automation, and payment providers. Some of these leave clear fingerprints in the page HTML; others are harder to detect from the outside.
Knowing a competitor's tech stack is genuinely useful information. It tells you what their engineering capacity looks like, which integrations they rely on, how they handle scale and performance, and what tools to benchmark against if you are shopping for your own stack.
What RankNibbler Detects
| Category | Technologies Identified |
|---|---|
| CMS | WordPress, Shopify, Squarespace, Wix, Drupal, Joomla, Ghost, Webflow, HubSpot, Magento, Craft CMS, Sanity, Contentful |
| E-commerce | WooCommerce, BigCommerce, PrestaShop, Magento, Shopify |
| JS Frameworks | React, Next.js, Nuxt.js, Angular, Vue.js, Svelte, SvelteKit, Gatsby, Astro, Remix |
| Analytics | Google Tag Manager, Google Analytics, Hotjar, Microsoft Clarity, Plausible, Matomo, Fathom |
| CDN | Cloudflare, CloudFront, Akamai, Fastly, Vercel, Netlify, Cloudflare Pages |
| CSS Frameworks | Bootstrap, Tailwind CSS, Bulma, Material UI, Chakra UI, Font Awesome |
| SEO Plugins | Yoast SEO, Rank Math, All in One SEO, Schema Pro |
| Marketing / Chat | Intercom, Zendesk, Drift, Crisp, HubSpot, Tawk.to |
| Email / CRM | Mailchimp, Klaviyo, ConvertKit, ActiveCampaign, HubSpot |
| Other | jQuery, reCAPTCHA, hCaptcha, cookie consent platforms, payment processors |
How Detection Works
Tech detection relies on fingerprints — patterns in the page source that are unique to specific technologies. Common signals include:
- Script URLs. A script loaded from
cdn.shopify.comstrongly implies Shopify; a bundle named_next/static/chunksimplies Next.js. - Meta tags. WordPress outputs
<meta name="generator" content="WordPress">; Ghost includes similar identifying meta. - HTML comments. Some CMSs leave identifying comments in generated HTML.
- CSS class patterns. Tailwind's utility classes (
flex,text-xl,p-4) are distinctive; Bootstrap usescontainer,row,col-. - File paths.
/wp-content/→ WordPress;/_astro/→ Astro. - HTTP headers. Server headers often identify the CDN (Cloudflare, Fastly) or origin infrastructure.
- Cookies. Session cookie names can reveal platforms.
The checker combines these signals to produce confident detection. Some technologies are harder to detect than others — headless CMSs (Contentful, Sanity) leave few fingerprints in the rendered output because the front end could be any framework.
Why Detect a Site's Tech Stack?
Competitor Research
Understanding what your competitors run tells you what they prioritise. A competitor on Shopify Plus is handling meaningful e-commerce scale. A competitor on a headless stack has invested in engineering resources. A competitor on WordPress with 50 plugins probably cannot iterate fast.
Sales Qualification (SaaS and Agencies)
SaaS sales teams check prospect tech stacks before reaching out. A company on WooCommerce is a prospect for e-commerce SaaS; a company on Webflow might want content-heavy integrations. Agencies check stacks to scope migration projects.
Platform Shopping
If you are deciding between Shopify, WooCommerce, and BigCommerce, see what competitors in your niche actually run — real adoption data beats marketing pages.
Security & Vulnerability Research
Security teams scan their own sites' tech stacks to verify no unexpected libraries or outdated frameworks are loaded.
Technical Due Diligence
During acquisitions or investments, understanding the target company's tech stack is part of due diligence — old jQuery-based sites require different remediation than modern React SPAs.
Limitations of Tech Detection
Tech detection from public HTML has blind spots:
- Backend languages. Cannot tell PHP from Python from Node.js from raw HTML.
- Databases. PostgreSQL vs MySQL vs MongoDB is usually invisible externally.
- Server-side frameworks. Django vs Rails vs Laravel rarely leaves front-end fingerprints.
- Headless CMS. Content could come from Contentful, Sanity, or a custom API — externally indistinguishable.
- Single-page apps. React apps can be built with any backend; the rendered output reveals React but not the API layer.
Related Tools
- HTTPS checker — related security and URL structure audit.
- CSS/JS file counter — understand request profile.
- Website speed test — tech stack affects performance.
- Site Audit — tech stack detection plus 30+ other checks.
- SEO Compare — compare tech and SEO signals across multiple sites.