Download websites that use Mono

About Mono

Server side runtimes are the hardest thing to count from outside a network, because a runtime has no reason to announce itself to visitors. Mono is a good example of the problem and of why the answer is still worth having. The runtime is an open implementation of the .NET framework built to run application code on Linux, macOS and other platforms that Microsoft originally did not target, and it does its work long before anything reaches the browser.

What a detection implies is a deployment decision rather than a design preference. A public site associated with this runtime usually means C# application code running on hardware or an operating system where the official stack was not an option at the time the system was built. The runtime dates to 2004, passed from its original authors through Xamarin into corporate stewardship, and has since been handed on again to the WineHQ organisation, so the WineHQ value recorded here names one stage of that chain rather than the project's current home. The code remains under a MIT license. Since official cross platform support arrived later and absorbed the mainstream case, web facing installs now skew towards older applications, appliance interfaces, vendor shipped software and embedded control panels that were never rewritten.

Those are precisely the systems that interest a modernisation practice or a security team. A runtime that no longer receives first class attention still carries the application it was chosen for, and knowing which public hosts sit on top of one is the starting point for both a migration pitch and a risk inventory. Hosting providers and infrastructure vendors have a similar interest in knowing which of their customers are pinned to it.

Honesty about method matters more here than in the browser facing categories. Evidence comes from response headers, error output and occasional path conventions, and every one of those can be stripped by an administrator, rewritten by a reverse proxy or hidden behind a content delivery network. As of October 2026 we detect 288 sites in the Development grouping, and the correct interpretation is a floor. Real deployment is larger, and the gap is not measurable from outside, so we do not pretend to know its size.

That limitation is also the argument for a list instead of a lookup. Checking one domain tells you whether the headers happen to be exposed on that host today. A full export lets you work with the population that does expose itself: which web servers front these hosts, which countries and top level domains they cluster under, which other server side technologies travel with them, and how the set shrinks as applications get rewritten. Trends in a leaky signal are still informative, and trends need the whole set.