Even when it identifies the specific project, it doesn't know C#. I took some scans of some notable CMS websites (so the programming language is provably correct).

WordPress.org (PHP, correctly identified language and framework): https://radar.cloudflare.com/scan/88fcab24-5e27-4c77-8ace-94...

Orchard Core (C#, Modern .Net, correctly identified framework): https://radar.cloudflare.com/scan/88adbf69-c010-4074-a80f-03...

DotNetNuke (C#, .Net Framework, correctly identified framework): https://radar.cloudflare.com/scan/7889b8b9-4fed-43b6-8506-49...

Yeah, it doesn't detect C# for some reason and for some of our own sites, it even failed to detect that those were built with .NET (as we intended;)).

> it even failed to detect that those were built with .NET (as we intended;)

Yeah, I'm pretty embarrassed to like a Microsoft product too.

ASP.NET could mean a bunch of programming languages and I'm assuming that a ASP.NET Server doesn't disclose that. It's probably safe to guess mostly C#, but that requires a different metric.

'Tis true. I used to know an absolute ton of big sites that were written in 100% VB.NET ASP.NET. I'd still be writing all my backend in VB.NET if it wasn't a second tier .Net language these days.

The 10% share for ASP.NET among the top 5,000 domains shows that .NET (and therefore also C#) is a very serious player in building web apps and APIs and for good reason. .NET is a solid, fast, secure, and mature technology, and it's only getting better. All other significant frameworks were JS based, which is no surprise to anyone, as a lot of modern sites are built as SPAs.

Are they using headers for identification? If so, it could be skewed by orgs masking some/all. I’m quite curious myself.