Website Technology Stack Checker - Free Scan

A website technology stack checker shows what a site is built with. Enter any URL or domain in this free tool and it detects the programming language, backend framework, CMS, analytics, ads, payments, server, CDN and DNS setup, giving each technology a probability score so you know how much to trust it.

What Is a Website Technology Stack?

A website technology stack is the combination of languages, frameworks, software and services that build and run a site. Think of it as the parts list behind the pages you see.

The stack has several layers. The backend holds the programming language (PHP, Python, Ruby, Java) and any framework on top of it. A content management system (CMS) such as WordPress or Shopify usually sits on that layer. The delivery layer covers the web server software, a content delivery network (CDN) and DNS. Third-party services then add analytics, advertising and payment processing.

Sites do not publish this list, but they leak clues. Response headers can name the server, cookies often hint at the backend language, page markup carries generator tags and script paths, and DNS records show where a domain points. This tool reads those signals and turns them into a ranked list of likely technologies.

How to Use the Website Technology Stack Checker

You need only a domain or address, and the scan takes a few seconds. Follow these steps:

1. Type or paste a domain or full address into the Website URL or Domain field. Entering example.com works. If you leave off the protocol, https is added for you.
2. Click Detect Technologies. The button changes to "Detecting..." while the scan runs.
3. Read the summary strip: the host, the HTTP status, how many technologies were found, response time in milliseconds, page size in KB and any redirects. The Server and X-Powered-By values appear there when the site sends them.
4. Review Languages & Backend Frameworks first, then the other groups below it. Each technology shows a percentage and, when detectable, a version number.
5. Open Detection evidence to see which signals triggered each result. Open DNS Records and All response headers for the raw data.
6. Click Copy results to paste the list elsewhere, or Download JSON to save the full analysis.

Worked Example: Scanning a WordPress Blog

Here is a realistic, illustrative scan showing how to turn a result into a conclusion. Suppose you enter a food blog's domain, and the tool returns HTTP 200, 7 technologies and a response time of 640 ms.

• Languages & Backend Frameworks: PHP at 92%.
• CMS: WordPress at 97%, with a version number.
• Server: Nginx at 90%.
• CDN: Cloudflare at 95%.
• Analytics: Google Analytics at 85%.

WordPress scores high because several independent signals agree, such as page markup, URL patterns and a PHP cookie or header. The Detection evidence panel lists them one by one. The practical reading: the blog runs on PHP with WordPress, sits behind Cloudflare, and tracks visits with Google Analytics. If you are a competitor, a developer pitching a rebuild, or a freelancer scoping a migration, you now know the platform without asking anyone.

How Do You Read the Probability Scores?

A probability score is the tool's confidence that a technology is really in use, based on how many independent signals point to it. Scores are capped at 99%, because no outside check can be 100% certain.

These ranges are a practical reading guide, not official thresholds:

What the summary strip tells you

The HTTP status shows whether the page loaded normally. A 200 is healthy, while a 403 or 503 often means a firewall or bot filter limited what the tool could see. The redirect count matters too: a result of 2 redirects usually means the address you typed bounced to another version, such as www or https. Page size and response time give a quick performance snapshot, and you can follow up with the GZIP compression checker if the page looks heavy.

What the evidence and headers tell you

The Detection evidence list is the part to trust over the percentage. A technology backed by a specific header plus a file path is stronger than one backed by a single text match. The full header list is also useful for troubleshooting caching and security settings, and the HTTP header checker goes deeper on that.

Who Needs a Website Tech Stack Lookup?

Anyone who works with websites benefits from knowing what runs underneath one. Common situations include:

• Competitor research: see whether rivals use Shopify, WordPress or a custom build, and which analytics and ad tools they run.
• Migration planning: confirm the current CMS and server before quoting a move or a redesign.
• Sales prospecting: agencies and SaaS teams find sites that use a specific platform or lack a CDN.
• Security review: a visible version number on an old CMS is a reason to patch or hide it.
• Learning: developers see how well-known sites combine languages, hosting and third-party services.

After you map the stack, a website reviewer audit shows how that stack performs for SEO, and the website value calculator helps put a price on a site you are evaluating.

Best Practices and Troubleshooting

Better input gives better output, and most surprises have a simple cause.

The tool says "Please enter a valid URL"

Check for spaces, typos or a missing dot in the domain. Use a plain domain or one full address. The address must also be publicly reachable, so local and private addresses are rejected.

The tool says "Could not fetch that URL"

The site may be down, blocking automated visits or timing out. Run it through the website down checker to see whether the site responds at all, then try again.

No technologies were identified

This happens when a site hides its signature behind a proxy, uses a static or JAMstack setup, or runs custom code. It does not mean the site has no stack. Look at the DNS Records and All response headers panels, since a CNAME or a custom header can still point you to a host or CDN.

The result differs from what you expected

Scan the exact page you care about. A marketing site on one platform may have a store or blog on a subdomain with a different one, so test each subdomain separately. Save a JSON export before and after a migration to document the change.

What Are the Limits of Technology Detection?

Detection from the outside is an informed inference, not a look inside the server. Heavily client-side apps may under-report because most of their code loads after the first response. A CDN or security layer can mask the origin server, and a site owner can remove version strings and generator tags on purpose. Backend databases and private services are rarely visible at all.

Treat the output as a strong starting point, then confirm anything important with another source such as the site owner, a code repository or hosting records.

Run the website technology stack checker above on your own domain or a competitor's, read the evidence behind each score, and export the results as JSON for your notes. For more diagnostics, browse the Website Audit & Performance tools.