Some of us who have joined the "dark side" of the force enjoy finding at least minimal Vi emulation modes, with most common edit operations available. However, a more complete version of Vi emulation would be nice, but adding regex would be drop-in, right?

I would like to embed the Widget on my and to preform functions on it such as load a snippet to the editor or append and remove lines.
This would allow me to create tutorials like tryfsharp.org

Why is the list limited to 10 fiddles? We should be able to see all of them, or at least have a page size option.

Could you add support for snippets? E.g. typing 'ctor' and pressing 'Tab' key 2 times should generate a class constructor just as it does in Visual Studio.
For some developers it could increase productivity.

please! Make app for windows phone. It will be wonderfull!

Given that MS have stopped supporting 4.5.1 and dotnet core has been released, it would be a good time to update the examples.

I would love to use .NET Fiddle in the documentation pages for my OSS projects, but I can't install the packages (I think because of the Framework verisons)

I'd like to have an option do not use "Console.WriteLine"...

Instead of
===============================
using System;
using System.Globalization;
using System.Text.RegularExpressions;

public class Program
{
public static void Main()
{
Console.WriteLine("Hello World");
Console.WriteLine(DateTime.Now.ToString("d", CultureInfo.CreateSpecificCulture("es-CL")));
Console.WriteLine(Regex.Replace("tot{o}", "{O}", "*", RegexOptions.IgnoreCase));
}
}
===============================

use simplified code like:
===============================
using System;
using System.Globalization;
using System.Text.RegularExpressions;

?"Hello World"
?DateTime.Now.ToString("d", CultureInfo.CreateSpecificCulture("es-CL")))
?Regex.Replace("tot{o}", "{O}", "*", RegexOptions.IgnoreCase)
===============================

Please allow users to have default templates and custom usings on loading.
Different users use different nuget packages and namespaces and want to have them declared when launching the website instead of having to add them manually each time anew.

Sometimes I need to check a code that works with local timezone which should be different from UTC. It would be great to have an ability to specify timezone in that cases. Thank you!

So that we can create asynchronous sample in DotNetFiddle

This is especially valuable with MVC fiddle type as one cannot add additional views or define their own routing.

Allow the usage of debugging such as stepping into a function, out of a function, run, memory mapping, local variables and the whole nine yards. It is vital if you don't want users to write constantly Console.WriteLine() statements.

Kindly, add debugging!

allow us to

1) View the compiled razor
2) allow code folding of codetags and collapse/expand code for readability

Add Web Api 2.2 to list of project type

ScriptCS has a syntax for loading assemblies and works better as a single file. I don't know if you plan on allowing .NET Fiddles (?...is that the plural of the thing you make in .NET Fiddle?) to load other assemblies, but I think it would be really cool to be able to do that.

Currently, dotNetFiddle throws when trying to use Akka.NET.
There is an error message saying that some methods in JSON.NET are missing.
We would love to have the ability to run live Akka samples from our docs site.

We need the same quick keyboard shortcuts as visual studio...
CTRL+D - Duplicate line
CTRL+K+C - Comment out line
CTRL+K+U - Uncomment line
ALT+ENTER - Automatically add or suggest missing namespace reference and add usings to the class (like resharper)

Support for System.ServiceModel would be very helpful.