Tech stack checker
See what a website is built on — the CMS, the framework, the analytics, the CDN.
What it looks at
The public HTML of the home page and the headers the server sends back with it. Thirty signatures cover the platforms most sites are built on, the frameworks behind them, the analytics and advertising scripts loaded into them, and the CDN in front.
Nothing is logged into and nothing is scanned. This is the same information any visitor could read by opening the page source — it is simply read faster and organised.
The version number problem
WordPress publishes its exact version in a generator meta tag unless somebody removes it. So do several other systems. That is a convenience for the software and a gift to anyone running a scanner: a list of sites on a version with a known vulnerability is trivial to assemble.
If this check reports a version number, that number is public. Removing the tag is not security by itself — you still have to apply the update — but there is no reason to advertise which update you have not applied yet.
Why you might be checking someone else
Most people run this on a competitor, a site they admire, or one they are about to inherit. All three are legitimate: the technology behind a public website is public.
If you are looking at a site you are about to take over, the useful question is not which CMS it uses but how many page builders are stacked on top of each other. A WordPress site running two builders and forty plugins is a rebuild, not a redesign, and it is better to know that before quoting.