diff --git a/Activout.RestClient.Newtonsoft.Json.Test/RestClientTests.cs b/Activout.RestClient.Newtonsoft.Json.Test/RestClientTests.cs
index 6dfd237..fe34ad3 100644
--- a/Activout.RestClient.Newtonsoft.Json.Test/RestClientTests.cs
+++ b/Activout.RestClient.Newtonsoft.Json.Test/RestClientTests.cs
@@ -197,7 +197,7 @@ public async Task TestPostJsonAsync()
                 .Respond(request =>
                 {
                     var content = request.Content!.ReadAsStringAsync().Result;
-                    content = content.Replace("\"ReviewId\":null", "\"ReviewId\":\"*REVIEW_ID*\"");
+                    content = content.Replace("{", "{\"ReviewId\":\"*REVIEW_ID*\", ");
                     return new StringContent(content, Encoding.UTF8, "application/json");
                 });
 
diff --git a/Activout.RestClient.Newtonsoft.Json/NewtonsoftJsonDefaults.cs b/Activout.RestClient.Newtonsoft.Json/NewtonsoftJsonDefaults.cs
index e551508..1e4b677 100644
--- a/Activout.RestClient.Newtonsoft.Json/NewtonsoftJsonDefaults.cs
+++ b/Activout.RestClient.Newtonsoft.Json/NewtonsoftJsonDefaults.cs
@@ -1,5 +1,6 @@
 using System.Diagnostics.CodeAnalysis;
 using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
 using Newtonsoft.Json.Serialization;
 
 namespace Activout.RestClient.Newtonsoft.Json;
@@ -12,21 +13,31 @@ public static class NewtonsoftJsonDefaults
         MediaType.ValueOf("application/json")
     ];
 
-    public static readonly JsonConverter[] DefaultJsonConverters = [new SimpleValueObjectConverter()];
+    public static readonly JsonConverter[] DefaultJsonConverters =
+    [
+        new IsoDateTimeConverter(),
+        new SimpleValueObjectConverter(),
+    ];
 
     public static readonly DefaultContractResolver CamelCasePropertyNamesContractResolver = new DefaultContractResolver
     {
-        NamingStrategy = new CamelCaseNamingStrategy()
+        NamingStrategy = new CamelCaseNamingStrategy(false, false)
     };
 
     public static readonly JsonSerializerSettings DefaultJsonSerializerSettings = new()
     {
-        Converters = DefaultJsonConverters.ToList()
+        Converters = [new StringEnumConverter(), ..DefaultJsonConverters],
+        NullValueHandling = NullValueHandling.Ignore
     };
 
     public static readonly JsonSerializerSettings CamelCaseSerializerSettings = new()
     {
-        Converters = DefaultJsonConverters.ToList(),
+        Converters =
+        [
+            new StringEnumConverter(CamelCasePropertyNamesContractResolver.NamingStrategy!),
+            ..DefaultJsonConverters
+        ],
         ContractResolver = CamelCasePropertyNamesContractResolver,
+        NullValueHandling = NullValueHandling.Ignore
     };
 }
\ No newline at end of file
diff --git a/Activout.RestClient.Newtonsoft.Json/RestClientBuilderNewtonsoftJsonExtensions.cs b/Activout.RestClient.Newtonsoft.Json/RestClientBuilderNewtonsoftJsonExtensions.cs
index dc8dc5d..5dd23a7 100644
--- a/Activout.RestClient.Newtonsoft.Json/RestClientBuilderNewtonsoftJsonExtensions.cs
+++ b/Activout.RestClient.Newtonsoft.Json/RestClientBuilderNewtonsoftJsonExtensions.cs
@@ -1,6 +1,4 @@
 using Newtonsoft.Json;
-using System.Collections.Immutable;
-using System.Diagnostics.CodeAnalysis;
 
 namespace Activout.RestClient.Newtonsoft.Json;