gistfile1.xml

<policies>
    <inbound>
        <base />
        
        <set-variable name="Channel" value="
            @{
                try {
                    var request = context.Request.Body.As<JObject>();
                    return request["content"]["channel"].ToString();
                }
                catch (Exception e) {
                    return "none";
                }
            }" />
        
        <set-variable name="IsTrial" value="@(context.User.Groups.Where(g => g.Name == "ApiTrial").Count() > 0)" />
        
        <rate-limit-by-key calls="2" renewal-period="10"
            increment-condition="@(context.Variables.GetValueOrDefault("IsTrial", false))"
            counter-key="@(String.Join("_",
            context.Subscription.Id,
            "ApiTrial",
            context.Variables.GetValueOrDefault("IsTrial", false).ToString(),
            (string) context.Variables["Channel"]))" />
            
    </inbound>
</policies>