Free tool — no signup required
A free website tech stack checker: CMS, JavaScript framework, analytics, CDN, e-commerce platform and more — each with a confidence score and the exact evidence it was detected from.
Tech detection is one of nine checks in the full API — SEO audit, security-header grading, public contacts, product data, and AI-ready Markdown, all from the same one HTTP call. Free tier, 1,000 requests/month, no card required.
Try the full API free →Paste any URL above and this free tool fingerprints the technologies running behind the page. It groups what it finds by category and scores each detection so you can tell a certain match from a weak signal:
Every match comes with a confidence score from 0 to 100% and the exact evidence it was detected from — a script URL, a header, a meta tag or a cookie — so you can verify it yourself instead of trusting a black box.
The checker reads only what the page already sends to any visitor's browser. It never logs in, never runs the site's JavaScript and never scans for vulnerabilities. Detection comes from four passive signals:
<meta name="generator"> tag/wp-content/, cdn.shopify.com or /_next/static/Server, X-Powered-By and CF-RayBecause it is a passive check, a site with a custom in-house backend or a heavy reverse proxy in front of it may expose few fingerprints or none at all. That is a limitation of every website technology checker, this one included — a blank result usually means "nothing detectable from the outside," not "nothing there."
| This tool | Wappalyzer | BuiltWith | |
|---|---|---|---|
| Price for a URL lookup | Free, unlimited | Free (extension) | Limited free |
| Signup or API key to start | None | Account for API | Account for API |
| Free JSON API | Yes — 1,000 req/mo | Paid only | Paid only |
| Confidence score + evidence shown | Yes | Partial | No |
| Open source detector | Yes (MIT) | No | No |
| Historical / ownership data | No | No | Yes |
BuiltWith is the better choice if you need historical adoption trends or firmographic lookups across millions of domains. For a quick, honest "what is this site built with" answer — with the evidence attached and a free API behind it — this tool is built for that.
Need this for many sites, or wired into a spreadsheet or a workflow? The full API returns the same tech-stack data as JSON from one HTTP call, alongside eight other checks — SEO audit, security headers, metadata, public contacts and AI-ready Markdown — on a free tier of 1,000 requests a month.
Paste the website's URL into the box above and press Check. The tool fingerprints the CMS, JavaScript framework, analytics, CDN and e-commerce platform from the page's HTML, script URLs, response headers and cookies, and shows each one with a confidence score and the evidence it matched on. No signup and no API key.
Yes. This page is completely free with no account, no API key and no limit on how many URLs you can check. The API it is built on also has a free tier of 1,000 requests a month if you want the same tech-stack data as JSON.
Enter the address and the checker groups everything it detects by category: CMS, framework, analytics, CDN, e-commerce, UI library and fonts. It works from signals the page already sends to any browser, so you get an answer in a second or two without installing anything.
It is a passive check, so it is reliable for anything that leaves a fingerprint in the HTML, scripts, headers or cookies, which covers most mainstream CMSs, frameworks, analytics tools and CDNs. Custom in-house backends and heavily proxied sites expose little and may return few results. Every tech-stack checker shares this limit.
Yes. React, Next.js, Vue, Nuxt, Angular, Svelte, Gatsby and similar frameworks are detected from their build output and runtime markers, each with a confidence score.
Not on this page, which handles one URL at a time. The full API takes one URL per call plus a batch endpoint for up to 10 URLs, returning the same data as JSON. The free tier is 1,000 requests a month.
Wappalyzer is mainly a browser extension plus a paid API. This is a URL-based check with a free JSON API and an open-source (MIT) detector, and every result here shows the evidence each technology was matched on.