A tech stack checker shows what technologies a website is built with by reading what the site sends to every visitor: HTTP headers, HTML, scripts, and cookies. Enter any URL below and Groooh's free checker reports its framework, CMS, hosting, analytics, and libraries in seconds, with no signup.
For a quick lookup of one website, this tool covers it. For bulk lead lists, technology history, or change alerts, see the comparison further down this page.
A website technology detector requests a page like a normal visitor, then compares what comes back against a library of known fingerprints: response headers, cookie names, meta tags such as the generator tag, script file URLs, and HTML or JavaScript patterns. Each match points to a specific technology.
The checker requests the URL you enter and records the response headers, the HTML, and the scripts it references.
Servers announce themselves in headers, frameworks leave marks in script paths and page attributes, and platforms such as WordPress and Shopify set telltale cookies and meta tags.
Each signal is compared with rules for known technologies. A script path that contains /_next/, for example, points to Next.js.
Some detections imply others. Finding WordPress, for instance, implies PHP.
Weak matches are less reliable than strong ones, so Groooh's report includes a confidence rating for each detection.
Groooh's checker reads response headers, script sources, meta tags, DNS hints, and DOM attributes and compares them with more than 150 technology signatures.
Wappalyzer-style detectors check a page when you ask, using fingerprint rules. BuiltWith works differently: it says it indexes the internet the way a search engine does and takes no data from third parties, which is how it keeps years of history (BuiltWith plans). A live check and a crawled database can show different results for the same site.
Groooh's checker detects frontend frameworks, styling libraries, CMS and e-commerce platforms, hosting and CDN providers, and analytics and tracking tools. Each detection is grouped by category in the report.
| Category | Examples it detects | Typical signals |
|---|---|---|
Frontend frameworks | React, Next.js, Vue.js, Nuxt, Angular, Svelte, Remix, Gatsby, Astro | Script bundle paths, page attributes, JavaScript globals |
Styling and CSS | Tailwind CSS, Bootstrap, Emotion, Styled Components, MUI, Chakra UI, Sass | Stylesheet and class patterns, loaded style libraries |
CMS and e-commerce | WordPress, Webflow, Shopify, WooCommerce, Medusa, Strapi, Ghost, Sanity | Generator meta tags, content paths, platform cookies, API endpoints |
Hosting and CDN | Vercel, AWS, Cloudflare, Netlify, DigitalOcean, Fastly, Google Cloud | Response headers, DNS hints |
Analytics and tracking | Google Analytics 4, Google Tag Manager, PostHog, Mixpanel, Hotjar, Segment, Heap, Plausible | Script URLs, inline snippets, tag containers |
The examples are a sample, not the full list. The report also shows server technology and a confidence rating for each match, and you can export results as JSON or CSV.
Paste the website's address into a tech stack checker and read the categorized report. With Groooh's checker the whole process takes a few seconds and needs no account.
Type a live address such as stripe.com or shopify.com into the box above.
Select Analyze Website. The checker fetches the page and compares its signals with the technology signatures.
Detections are grouped by category, such as frameworks, CMS, hosting, and analytics, each with a confidence rating.
Download the results as JSON or CSV, or run a second site and compare the two.
You can find many clues yourself. Open the page source and search for a generator meta tag, which often names the CMS. Look for paths such as /wp-content/, which indicate WordPress. In your browser's developer tools, open the Network tab, select the page request, and read the response headers, where the server, CDN, and hosting provider often show up. A checker does the same work faster and across many more signatures.
For a quick lookup of one website, free options include Groooh's checker, WhatRuns, and BuiltWith's own free lookup. For lead lists, bulk data, history, or alerts, the established paid options are Wappalyzer, from $250 a month, and BuiltWith, from $295 a month. Both BuiltWith and Wappalyzer offer a free way to check a single site, so what separates these tools is what you need beyond one lookup.
| Tool | Best for | Free option | Paid plans | Main limits |
|---|---|---|---|---|
This ToolGroooh Tech Stack Checker | Fast one-site lookups with no account | Free, no signup, JSON and CSV export | None | More than 150 signatures. Not built for bulk lists, history, or alerts |
| Wappalyzer | Lead lists, API access, and CRM enrichment | Free account with 50 technology lookups a month | Pro $250 a month, Business $450, Enterprise from $850 | Lead lists, APIs, and CRM integrations need a paid plan |
| BuiltWith | Market research, technology history, and lead lists | Free individual site lookups | Basic $295 a month, Pro $495, Team $995 | Monthly plans have a one-month minimum and yearly plans a one-year term |
| WhatRuns | A free browser extension | Free Chrome extension, no signup | No paid plan listed on its homepage | Extension only, and focused on single sites |
| WhatWeb | Developers who prefer the command line | Free and open source | None | Command line only |
Prices checked on October 20, 2026 from each vendor's own page, and they change often, so confirm before you buy. Sources: Wappalyzer pricing, BuiltWith plans, WhatRuns, and Koala's roundup of Wappalyzer alternatives for WhatWeb.
Any of the free options. Pick the one that fits how you work, such as a web page, a browser extension, or a command line.
Wappalyzer or BuiltWith.
BuiltWith, which keeps years of history.
WhatWeb, or the Wappalyzer or BuiltWith APIs on a paid plan.
Tech stack detection is reliable for technologies a site exposes publicly, and blind to everything it keeps private. A checker can only report what any visitor's browser also receives.
Internal databases such as PostgreSQL, MySQL, or MongoDB sit behind the server and cannot be queried from outside. A checker can only flag client-exposed interfaces, such as Firebase, Supabase, GraphQL endpoints, or headless CMS APIs.
If a site sits behind a service such as Cloudflare, you will see the CDN, not necessarily the host or server behind it.
Tools that read only the initial page response may not see scripts that JavaScript loads afterward.
Many sites hide version numbers in headers and meta tags.
New tools appear faster than detection rules, so a very new library may not be recognized yet. That is why each detection carries a confidence rating.
Sites with bot protection or firewalls may refuse the request or return a partial page.
Developers, agencies, marketers, founders, and security teams use tech stack checkers to learn what a site runs on before they make a decision about it.
| Who | What they use it for | Example |
|---|---|---|
| Developers and agencies | Scoping a redesign, rebuild, or migration | Finding out whether a client's site runs WordPress or a custom framework before quoting the work |
| Product and marketing teams | Competitor research | Seeing which analytics, CMS, and hosting stack a competitor uses |
| Founders and learners | Learning from sites they admire | Checking whether a popular product is built on Next.js, Remix, or Astro |
| Sales teams | Qualifying a single prospect | Confirming a company uses a platform before outreach. For lists by technology, use Wappalyzer or BuiltWith |
| Security and IT teams | Spotting exposed or outdated technology | Noticing an unexpected service or an old library on a public site |
If your check shows a site that needs modernizing, our team can help. We build and rebuild web and mobile products, from web development to mobile apps.
Contact EngineeringDirect, transparent answers regarding website technology detection, accuracy, legality, and competitor tools.
Enter the site's URL into a tech stack checker such as Groooh's free tool, and it reports the framework, CMS, hosting, and analytics it detects. You can also check by hand: view the page source for a generator meta tag, and read the response headers in your browser's developer tools.
Yes, it is free and needs no signup, registration, or browser extension. Results can be exported as JSON or CSV.
For a quick lookup of one website, yes. For bulk lead lists, technology history, change alerts, or CRM integrations, no, because Wappalyzer and BuiltWith are built for that. Both also offer free single-site checks, so choose by what you need beyond one lookup.
A detector requests a page like a visitor, then matches response headers, cookie names, meta tags, script URLs, and HTML or JavaScript patterns against known technology fingerprints. Some detections imply others, such as WordPress implying PHP, and a confidence rating shows how strong each match is.
No. Private databases such as PostgreSQL, MySQL, or MongoDB sit behind the server and cannot be seen from outside. A checker can only flag interfaces the site exposes to browsers, such as Firebase, Supabase, GraphQL endpoints, or headless CMS APIs.
Run the URL through a tech stack checker and look at the CMS category. To check by hand, view the page source for a generator meta tag, or look for paths such as /wp-content/, which indicate WordPress. Platforms such as Shopify and Webflow also leave recognizable signals.
A checker reads only public information that every visitor's browser already receives, similar to loading the page. Respect each site's terms and avoid scanning at a volume that could strain it. This is general information, not legal advice.
Tools use different methods. Some check the live page with fingerprint rules, while others, like BuiltWith, keep a crawled database. They also differ in rule versions, whether they run JavaScript, and how they treat weak matches, so results can vary at the margins.
If the report shows a stack that is holding a site back, or you are planning a new web or mobile product, Groooh designs and builds production-ready software. Tell us what you are working on and we will recommend a practical stack.
Built and maintained by the Groooh engineering team. Last updated October 19, 2026.