SignalR : use camel case

Roll your own Conttract resolver like

public class SignalRContractResolver : IContractResolver
{

    private readonly Assembly assembly;
    private readonly IContractResolver camelCaseContractResolver;
    private readonly IContractResolver defaultContractSerializer;

    public SignalRContractResolver()
    {
        defaultContractSerializer = new DefaultContractResolver();
        camelCaseContractResolver = new CamelCasePropertyNamesContractResolver();
        assembly = typeof(Connection).Assembly;
    }

    public JsonContract ResolveContract(Type type)
    {
        if (type.Assembly.Equals(assembly))
        {
            return defaultContractSerializer.ResolveContract(type);

        }

        return camelCaseContractResolver.ResolveContract(type);
    }

}

Register it like

var settings = new JsonSerializerSettings();
settings.ContractResolver = new SignalRContractResolver();
var serializer = JsonSerializer.Create(settings);
GlobalHost.DependencyResolver.Register(typeof (JsonSerializer), () => serializer);

If you use a custom IoC you can run into problems because JsonSerializer is a concrete type and some IoCs like for example Ninject will inject unbound concrete types. In Ninjects case the solution is to register it with Ninject instead of with SignalRs own DependencyResolver

var settings = new JsonSerializerSettings();
settings.ContractResolver = new SignalRContractResolver();
var serializer = JsonSerializer.Create(settings);
kernel.Bind<JsonSerializer>().ToConstant(serializer);

More info on my blog:
http://andersmalmgren.com/2014/02/27/why-overriding-jsonserializer-no-longer-work-in-signalr-2-0/