Of course, you can use it. Tools are under products at <a href="http:&#x2F;&#x2F;open.xamarin.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;open.xamarin.com&#x2F;</a><p>Microsoft has not open sourced Visual studio (VS) so similarly they will not open source Xamarin. You can also use .net framework without using VS. Just use command line tools