The [JavaScript client](xref:signalr/javascript-client) runs on the current [Node.js long-term support (LTS) release](https://nodejs.org/about/releases/) and the following browsers:
The JavaScript client doesn't support Internet Explorer and other older browsers. The client might have unexpected behavior and errors on unsupported browsers.
The [.NET client](xref:signalr/dotnet-client) runs on any platform supported by ASP.NET Core. For example, [Xamarin developers can use SignalR](https://github.com/aspnet/Announcements/issues/305) for building Android apps using Xamarin.Android 8.4.0.1 and later and iOS apps using Xamarin.iOS 11.14.0.4 and later.
If the server runs IIS, the WebSockets transport requires IIS 8.0 or later on Windows Server 2012 or later. Other transports are supported on all platforms.