01
Domain & registration
Registrar, registration and expiry dates, EPP status codes, DNSSEC signing and the authoritative nameservers — read from the registry over RDAP, the IETF successor to WHOIS.
Free Tool
See what any website is actually built on — with the evidence, not a guess.
Enter a URL and get its hosting, CDN, registrar, SSL certificate, DNS, email provider, frameworks and every third-party service it loads. Each finding shows the header, record or asset it was derived from, so you can check the work.
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Public data only
Evidence on every finding
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What it reads
Six independent sources, cross-referenced
Any one signal can mislead. A CDN masks the origin, a header can be stripped, a framework can be silent. Reading all six together is what turns a list of clues into a picture of the stack.
02
SSL / TLS certificate
Issuer, subject, validity window, days remaining, negotiated protocol and cipher, whether the chain validates, and every hostname the certificate covers. A certificate spanning thousands of unrelated names tells you who really terminates TLS.
03
Hosting, cloud & CDN
The IP addresses the site resolves to, their reverse DNS, and the autonomous system that announces them — which names the actual network operator even when the site advertises nothing in its headers.
04
DNS & email
A, AAAA, CNAME, NS, MX and TXT records, with SPF and DMARC pulled out and read. MX records identify the mail provider; SPF includes reveal transactional email vendors that appear nowhere else.
05
Frameworks & CMS
Server software, language runtime, frontend framework, CMS and ecommerce platform — matched from response headers, cookie names, runtime markers in the HTML and asset paths, with a version number wherever the evidence carries one.
06
Third-party services
Every external host the page loads from, resolved into named vendors: analytics, tag managers, payment processors, chat widgets, error monitoring, fonts and media CDNs. Each one is a data processor and an uptime dependency.
What it cannot see
The honest limits of any tool like this
Want the SEO side? The free SEO checker scores the same site on indexing, on-page and Core Web Vitals. Building with AI? Our directory of MCP servers, agent frameworks and dev tools lists what each one does, who it suits, and the trade-off.
- It does not run JavaScript. Anything injected after page load — most commonly scripts fired by a tag manager — will not appear.
- It reads the homepage only. A checkout, an app subdomain, or anything behind a login can be built on a completely different stack.
- Server-side technology that does not announce itself is invisible. Stripped headers usually mean a careful team, not an empty stack.
- A CDN or bot-management edge can hide the origin entirely, in which case the result describes the edge rather than the site.
- Registrant identity is redacted by registries under GDPR. No public tool can show it, whatever it claims.
FAQ
How this works, answered directly
01
How does a website technology checker work?
It gathers public evidence from five independent sources and matches it against known signatures. DNS records reveal the nameservers, mail provider and any services verified against the domain. The TLS handshake exposes the certificate, its issuer and every hostname it covers. HTTP response headers frequently name the server, framework and CDN outright. The HTML names the analytics, payment, chat and font providers the page loads. Finally, the IP address maps to an autonomous system, which identifies the network operator. No part of this requires access to the site — every signal is something the site already publishes to every visitor.
02
Is scanning a website like this legal?
Yes. This tool reads only what a site publishes publicly: DNS records, the certificate presented in a normal TLS handshake, the response headers and HTML sent to any browser, and public internet registry data. It makes a single ordinary GET request to the homepage — the same request your browser makes when you visit. It does not attempt authentication, probe for vulnerabilities, scan ports, enumerate directories, or send unusual traffic. That is the line between reconnaissance of public information and unauthorized access, and this stays firmly on the public side of it.
03
Why does the registrant's name and address not appear?
Because the registry no longer publishes it. Since GDPR took effect in 2018, most generic top-level domain registries redact registrant contact details from public WHOIS and RDAP responses, replacing them with the registrar's own details or a privacy service. The data still exists and is available to law enforcement and accredited requesters through formal channels, but no public lookup tool can show it. Any service that appears to have it is showing you either a pre-GDPR cached record or a paid third-party dataset.
04
How accurate is technology detection?
It depends entirely on the evidence, which is why every finding on this page shows the evidence it came from and a confidence level. A response header saying `x-powered-by: Next.js` is conclusive — that string does not appear by accident. An asset loaded from a vendor's CDN is strong but not conclusive, because a copied code snippet or an embedded widget can produce the same signal. A conventional file path is weakest, since unrelated software uses the same conventions. Detection also only sees the homepage: a checkout built on a different stack, or anything behind a login, is invisible to it.
05
What do missing security headers actually mean?
Each missing header is a browser-side defense the site has chosen not to enable, not a vulnerability in itself. No Content-Security-Policy means that if an attacker ever gets script onto a page, nothing constrains what it can do. No Strict-Transport-Security means a visitor's first request can be intercepted before the redirect to HTTPS. No X-Frame-Options means the site can be framed by another and used for clickjacking. A site can be perfectly secure with a low score here and badly broken with a perfect one — treat it as a quick signal about engineering hygiene rather than a verdict.
06
Why does the tool show fewer technologies than I expected?
Three common reasons. Server-side technology leaves no trace unless it announces itself, and many teams deliberately strip identifying headers — an absent framework is often good practice, not a detection failure. Scripts injected after page load by a tag manager are invisible to a single fetch, because nothing here executes JavaScript. And sites behind an aggressive bot-management edge may serve a challenge page rather than the real one, in which case you are seeing the edge's stack rather than the site's.
Free Engagement
We read stacks for a living.
Inheriting a codebase, evaluating an acquisition, or wondering why your own site is slow? A scan is the first ten minutes of that work. The rest is knowing what the findings mean and what to do about them.
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