What is this website built with? Detect CMS, framework and CDN

Sales research, competitor analysis, migration projects and security reviews all start with the same question: what is this site built with? You can view the source and guess, or ask for a structured answer.

What gives a technology away

A site reveals its stack in the pieces it sends to every visitor:

• Response headers: the web server, a CDN or hosting platform and sometimes the framework.
• Meta tags: many CMSs write a generator tag.
• Script and stylesheet URLs: framework bundles, analytics and tag-manager scripts, support widgets and payment libraries.
• Page markers: classes, attributes and comments that a framework or site builder leaves behind.

A detector reads one page and matches those signals. Each match is only as strong as its evidence, so a good result shows the evidence and a confidence level instead of a bare list of names.

One request

curl "https://api.ambolt.dev/v1/tech-stack-lookup?url=https://www.sitemaps.org/&free=1"

You get the detected technologies grouped by kind (CMS or site builder, framework, CDN and hosting, web server, analytics and tag managers, advertising pixels, support widgets, payments, consent tools), each with the header, meta tag or script URL that triggered it.

Reading the answer

• Evidence first. A detection that rests on a script URL is stronger than one that rests on a generic class name.
• Confidence is a hint, not a guarantee. Sites can hide or proxy their stack, and custom builds leave no trace.
• One page only. The tool reads the page you give it and respects robots.txt; other pages on the same site can use different technologies.

Limits

It does not see anything behind a login and it cannot detect technologies that leave no trace in the page the server returns.

Try it in the free website technology checker, or use the API for lists of URLs.