Tech Stack Checker
What is that site built with? We fetch the page and detect frameworks, CMS, analytics, hosting, and payment tools from live signatures.
What it detects
The checker looks for the fingerprints technologies leave in a page's HTML and response headers: Next.js's /_next/ assets, WordPress's wp-content paths, Shopify's CDN, Tailwind's utility classes, analytics snippets from Google, Plausible, PostHog and Segment, and hosting signatures from Cloudflare, Vercel, and Netlify. Detection is signature-based, so heavily customized or server-rendered-only stacks may show fewer results than a browser extension would.
How it works, and who it is for
When you submit a URL, the tool makes a single request to that page from our server with a nine-second timeout and reads the first 400 KB of the response. It never executes the page's JavaScript, so what you see is the stack visible in the delivered HTML and headers: the generator meta tag, asset paths such as /_next/ or /wp-content/, third-party script domains, and infrastructure headers like cf-ray or x-vercel-id. Around three dozen signatures are checked and grouped into framework, CMS, site builder, CSS, analytics, support, marketing, payments, hosting, fonts, and monitoring.
That makes it a fast first pass rather than a forensic audit. Competitive researchers use it to see which analytics and payment stack a rival ships, developers use it to check what platform a site they are about to integrate with runs on, and founders comparing site builders use it to see what companies at a similar stage actually chose. Because detection is signature-based, an empty result means no known fingerprint appeared in the HTML — not that the site uses nothing.
Frequently asked questions
›How do I find out what a website is built with?
Paste the domain into the box above and the checker fetches the page, then matches its HTML and response headers against a library of known technology signatures. It reports the framework or CMS, CSS toolkit, analytics, support and payment widgets, and the hosting or CDN layer. No extension or install is needed — the request runs on our server, not in your browser.
›Is the tech stack checker free?
Yes, it is free and needs no account or signup. Checks are rate-limited to 20 per minute per IP address to keep the service available; if you hit the limit, wait a minute and try again.
›Why does it detect fewer technologies than a browser extension?
Extensions run inside a real browser, so they see JavaScript that has already executed and the network requests it triggered. This checker reads the raw HTML response and headers only. Anything injected after page load — a tag manager firing a second-stage script, for example — will not appear, and heavily customised or fully server-rendered sites can look emptier than they are.
›Can it tell me who hosts a site or which CDN it uses?
Often, yes. Hosting and CDN detection comes from response headers rather than page content: Cloudflare via cf-ray, Vercel via x-vercel-id, Netlify, Fastly, and AWS CloudFront each leave identifiable headers. If a site sits behind a proxy that strips those headers, the origin host will not be detectable.
›Will the site owner see that I checked their site?
The check makes a single ordinary GET request to the homepage, which appears in the site’s server logs like any other visit. The request identifies itself with a NeuronFeedTools user agent. Nothing else is sent, no forms are submitted, and no pages beyond the URL you enter are crawled.
›Are the results always accurate?
Treat them as strong signals rather than proof. Signature matching can produce false positives — a page that merely mentions a library name, for instance — and false negatives when a site self-hosts scripts or renders everything server-side. Confirm anything important against the site’s own documentation or job listings.