What is this website built with?
Detect the CMS, framework, ecommerce platform, analytics, CDN, and hosting behind any website - in seconds. Free, no signup, passive and read-only.
Detects CMS, frameworks, ecommerce, analytics, CDN & hosting. Passive & read-only - nothing is stored.
What this tech stack checker detects
This free tool fetches any public web page and fingerprints the technologies behind it. It reads the page's HTML and HTTP response headers - exactly what your browser receives - and matches them against a library of known signatures. In a couple of seconds you get a plain-English summary of the primary stack, a grouped breakdown of every detected technology with the evidence used, and a short note on what it all means for performance, security, and your options.
CMS & website builders
WordPress, Shopify, Wix, Squarespace, Webflow, Drupal, Joomla, Ghost, HubSpot CMS, Framer, Duda.
Frameworks & libraries
Next.js, Nuxt, Gatsby, Astro, SvelteKit, Remix, plus React, Vue, Angular, jQuery, Bootstrap, and Tailwind.
Ecommerce & marketing
WooCommerce, Magento, BigCommerce, plus GA4, Google Tag Manager, Meta Pixel, HubSpot, Hotjar, Clarity, Plausible, and Segment.
CDN, hosting & fonts
Cloudflare, Vercel, Netlify, Fastly, Amazon CloudFront, Nginx, Apache, and Google Fonts.
How a CMS detector works
Every platform leaves fingerprints in the code it ships to the browser. A reliable detector cross-references several kinds of evidence rather than relying on any single clue:
- File paths. WordPress serves assets from
/wp-content/and/wp-includes/; Next.js ships from/_next/; Nuxt from/_nuxt/. - The meta generator tag. Many CMSs and static site generators announce themselves in
<meta name="generator">. - Platform CDNs. Assets from
cdn.shopify.comorwixstatic.comare dead giveaways. - Runtime globals.
__NEXT_DATA__,window.__NUXT__, and scoped Vue attributes reveal the front-end framework. - HTTP headers.
Server,X-Powered-By, and vendor-specific headers expose the server, CDN, and sometimes the platform.
This is the same approach popular tools like BuiltWith and Wappalyzer use. Our version is free, requires no signup or extension, and runs the scan server-side so you can use it anywhere.
Who uses a tech stack checker - and why
| Use case | What you learn |
|---|---|
| Sales & lead gen | Whether a prospect runs an outdated or limiting platform you can help them move off. |
| Competitive research | How competitors build, track, and host - and where you can outperform them. |
| Due diligence | The real stack behind a site you're considering buying, partnering with, or acquiring. |
| Migration planning | What you're moving from before scoping a replatform or rebuild. |
| Learning | How a site you admire is architected, down to the framework and CDN. |
When the stack signals it's time to rebuild
The platform a site runs on is one of the strongest predictors of its ceiling. WordPress powers a huge share of the web and is endlessly flexible, but plugin-heavy installs frequently struggle with Core Web Vitals, pile up security and maintenance overhead, and become fragile as they grow. Hosted builders like Wix, Squarespace, and Webflow are excellent for launching quickly, but they cap you on custom functionality, performance tuning, and technical SEO control. And legacy libraries such as old jQuery add weight and can carry known vulnerabilities.
None of those mean you should rebuild today. But if you're outgrowing your platform - slow pages, features you can't ship, a CMS that fights you - a modern custom or headless build (think Astro, Next.js, or a headless CMS) usually loads faster, ranks better, and is far easier to extend. The detector's summary flags these situations so you know when a deeper review is worth it.
Free BuiltWith alternative: how it compares
BuiltWith and Wappalyzer are the best-known tech lookup tools. For checking the stack behind a single site, this tool does the same core job - free, with no extension and no account. The paid tools add historical technology data and lead lists that this tool doesn't; for a quick "what is this built with?" lookup, here's how they stack up.
| Capability | This tool | BuiltWith | Wappalyzer |
|---|---|---|---|
| Detect CMS, framework, ecommerce, analytics, CDN | Yes | Yes | Yes |
| Instant single-URL scan, nothing to install | Yes | Yes | Browser extension or account |
| No signup or usage limits | Yes | Free lookups are limited | Free tier is limited |
| Plain-English "is it time to rebuild?" guidance | Yes | No | No |
| Historical tech data & lead lists | No | Yes (paid) | Yes (paid) |
| Cost | Free | Free tier; paid plans | Free tier; paid plans |
Frequently asked questions
- What is a website tech stack checker?
- A tool that fetches a website and identifies the technologies behind it - CMS, framework, ecommerce, analytics, CDN, and hosting - by reading the page's HTML and HTTP headers for known fingerprints.
- How do you detect what CMS a website uses?
- By cross-referencing file paths (e.g. /wp-content/), the meta generator tag, platform CDNs, runtime globals, and HTTP headers like Server and X-Powered-By.
- Is this tech stack checker free?
- Yes - completely free, no signup, no usage limits. The scan is passive and read-only, and nothing is stored.
- What technologies can it detect?
- CMS and builders, ecommerce platforms, JavaScript frameworks and libraries, analytics and marketing tools, CDN and hosting, and Google Fonts - 40+ technologies in total.
- Is checking a website's technology legal?
- Yes. The tool only requests the public page like any browser does and reads information the site already sends to every visitor. It never logs in or probes private endpoints.
- Why can't it detect anything on some sites?
- Some sites are hand-built, strip fingerprints via server-side rendering, sit behind caching/bot protection, or block automated requests. The tool then reports what it can and notes the uncertainty.
- Why would I want to know a site's tech stack?
- Common reasons include competitive research, lead generation and sales (spotting a prospect on an outdated platform), vendor due diligence before buying or partnering, planning a migration or rebuild, and simply learning how a site you admire is built.
- Should I rebuild a site that's on WordPress or a builder?
- Only if you're hitting limits on performance, functionality, SEO, or maintenance. A short technical review will tell you whether a custom or headless rebuild is worth it.
- Is this a free alternative to BuiltWith?
- Yes - for looking up a single site's stack it's a free, no-signup, no-extension alternative to BuiltWith and Wappalyzer. Their paid plans add historical tech data and lead lists this tool doesn't; for a quick lookup, this covers it.
Go deeper on the sites you check
Once you know the stack, see how it actually performs:
- DNS lookup - confirm the A, CNAME, and hosting records that reveal where a site really runs.
- Domain age & WHOIS checker - see how established the domain is and who registered it.
- Website speed test - Core Web Vitals and performance, where heavy platforms often fall down.
- Website modernization checker - a full scan for outdated design, mobile, and security signals.
- On-page SEO checker - see how well any page is optimized for search and AI.
- SSL & security headers checker - check how well the site is hardened.
For background on detection methodology, see the open-source Wappalyzer project.
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