diff --git a/CryptoExchange.Net.UnitTests/CallResultTests.cs b/CryptoExchange.Net.UnitTests/CallResultTests.cs
index 823fee8b..dd52d41d 100644
--- a/CryptoExchange.Net.UnitTests/CallResultTests.cs
+++ b/CryptoExchange.Net.UnitTests/CallResultTests.cs
@@ -121,6 +121,7 @@ public void TestWebCallResultSuccessAsError()
                 null,
                 HttpMethod.Get,
                 new List<KeyValuePair<string, IEnumerable<string>>>(),
+                ResultDataSource.Server,
                 new TestObjectResult(),
                 null);
             var asResult = result.AsError<TestObject2>(new ServerError("TestError2"));
@@ -150,6 +151,7 @@ public void TestWebCallResultSuccessAsSuccess()
                 null,
                 HttpMethod.Get,
                 new List<KeyValuePair<string, IEnumerable<string>>>(),
+                ResultDataSource.Server,
                 new TestObjectResult(),
                 null);
             var asResult = result.As<TestObject2>(result.Data.InnerData);
diff --git a/CryptoExchange.Net/Clients/RestApiClient.cs b/CryptoExchange.Net/Clients/RestApiClient.cs
index 02643489..81e1ebb8 100644
--- a/CryptoExchange.Net/Clients/RestApiClient.cs
+++ b/CryptoExchange.Net/Clients/RestApiClient.cs
@@ -668,47 +668,47 @@ protected virtual async Task<WebCallResult<T>> GetResponseAsync<T>(
                     if (error.Code == null || error.Code == 0)
                         error.Code = (int)response.StatusCode;
 
-                    return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, error!);
+                    return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, error!);
                 }
 
                 if (typeof(T) == typeof(object))
                     // Success status code and expected empty response, assume it's correct
-                    return new WebCallResult<T>(statusCode, headers, sw.Elapsed, 0, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, null);
+                    return new WebCallResult<T>(statusCode, headers, sw.Elapsed, 0, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, null);
 
                 var valid = await accessor.Read(responseStream, outputOriginalData).ConfigureAwait(false);
                 if (!valid)
                 {
                     // Invalid json
                     var error = new ServerError("Failed to parse response: " + valid.Error!.Message, accessor.OriginalDataAvailable ? accessor.GetOriginalString() : "[Data only available when OutputOriginal = true in client options]");
-                    return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, error);
+                    return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, error);
                 }
 
                 // Json response received
                 var parsedError = TryParseError(accessor);
                 if (parsedError != null)
                     // Success status code, but TryParseError determined it was an error response
-                    return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, parsedError);
+                    return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, parsedError);
 
                 var deserializeResult = accessor.Deserialize<T>();
-                return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), deserializeResult.Data, deserializeResult.Error);
+                return new WebCallResult<T>(response.StatusCode, response.ResponseHeaders, sw.Elapsed, responseLength, OutputOriginalData ? accessor.GetOriginalString() : null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, deserializeResult.Data, deserializeResult.Error);
             }
             catch (HttpRequestException requestException)
             {
                 // Request exception, can't reach server for instance
                 var exceptionInfo = requestException.ToLogString();
-                return new WebCallResult<T>(null, null, sw.Elapsed, null, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, new WebError(exceptionInfo));
+                return new WebCallResult<T>(null, null, sw.Elapsed, null, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, new WebError(exceptionInfo));
             }
             catch (OperationCanceledException canceledException)
             {
                 if (cancellationToken != default && canceledException.CancellationToken == cancellationToken)
                 {
                     // Cancellation token canceled by caller
-                    return new WebCallResult<T>(null, null, sw.Elapsed, null, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, new CancellationRequestedError());
+                    return new WebCallResult<T>(null, null, sw.Elapsed, null, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, new CancellationRequestedError());
                 }
                 else
                 {
                     // Request timed out
-                    return new WebCallResult<T>(null, null, sw.Elapsed, null, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), default, new WebError($"Request timed out"));
+                    return new WebCallResult<T>(null, null, sw.Elapsed, null, null, request.RequestId, request.Uri.ToString(), request.Content, request.Method, request.GetHeaders(), ResultDataSource.Server, default, new WebError($"Request timed out"));
                 }
             }
             finally
@@ -962,14 +962,14 @@ internal async Task<WebCallResult<bool>> SyncTimeAsync()
         {
             var timeSyncParams = GetTimeSyncInfo();
             if (timeSyncParams == null)
-                return new WebCallResult<bool>(null, null, null, null, null, null, null, null, null, null, true, null);
+                return new WebCallResult<bool>(null, null, null, null, null, null, null, null, null, null, ResultDataSource.Server, true, null);
 
             if (await timeSyncParams.TimeSyncState.Semaphore.WaitAsync(0).ConfigureAwait(false))
             {
                 if (!timeSyncParams.SyncTime || DateTime.UtcNow - timeSyncParams.TimeSyncState.LastSyncTime < timeSyncParams.RecalculationInterval)
                 {
                     timeSyncParams.TimeSyncState.Semaphore.Release();
-                    return new WebCallResult<bool>(null, null, null, null, null, null, null, null, null, null, true, null);
+                    return new WebCallResult<bool>(null, null, null, null, null, null, null, null, null, null, ResultDataSource.Server, true, null);
                 }
 
                 var localTime = DateTime.UtcNow;
@@ -998,7 +998,7 @@ internal async Task<WebCallResult<bool>> SyncTimeAsync()
                 timeSyncParams.TimeSyncState.Semaphore.Release();
             }
 
-            return new WebCallResult<bool>(null, null, null, null, null, null, null, null, null, null, true, null);
+            return new WebCallResult<bool>(null, null, null, null, null, null, null, null, null, null, ResultDataSource.Server, true, null);
         }
 
         private bool ShouldCache(RequestDefinition definition)
diff --git a/CryptoExchange.Net/Converters/SystemTextJson/ObjectStringConverter.cs b/CryptoExchange.Net/Converters/SystemTextJson/ObjectStringConverter.cs
index d6a50787..f2747cdc 100644
--- a/CryptoExchange.Net/Converters/SystemTextJson/ObjectStringConverter.cs
+++ b/CryptoExchange.Net/Converters/SystemTextJson/ObjectStringConverter.cs
@@ -25,7 +25,7 @@ public class ObjectStringConverter<T> : JsonConverter<T>
             if (string.IsNullOrEmpty(value))
                 return default;
 
-            return (T?)JsonDocument.Parse(value).Deserialize(typeof(T));
+            return (T?)JsonDocument.Parse(value!).Deserialize(typeof(T));
         }
 
         /// <inheritdoc />
diff --git a/CryptoExchange.Net/Objects/CallResult.cs b/CryptoExchange.Net/Objects/CallResult.cs
index 17e53ba0..5ee63bd1 100644
--- a/CryptoExchange.Net/Objects/CallResult.cs
+++ b/CryptoExchange.Net/Objects/CallResult.cs
@@ -349,6 +349,7 @@ public class WebCallResult<T>: CallResult<T>
         /// <param name="requestBody"></param>
         /// <param name="requestMethod"></param>
         /// <param name="requestHeaders"></param>
+        /// <param name="dataSource"></param>
         /// <param name="data"></param>
         /// <param name="error"></param>
         public WebCallResult(
@@ -362,6 +363,7 @@ public WebCallResult(
             string? requestBody,
             HttpMethod? requestMethod,
             IEnumerable<KeyValuePair<string, IEnumerable<string>>>? requestHeaders,
+            ResultDataSource dataSource,
             [AllowNull] T data,
             Error? error) : base(data, originalData, error)
         {
@@ -375,6 +377,7 @@ public WebCallResult(
             RequestBody = requestBody;
             RequestHeaders = requestHeaders;
             RequestMethod = requestMethod;
+            DataSource = dataSource;
         }
 
         /// <summary>
@@ -398,7 +401,7 @@ public WebCallResult(
         /// Create a new error result
         /// </summary>
         /// <param name="error">The error</param>
-        public WebCallResult(Error? error) : this(null, null, null, null, null, null, null, null, null, null, default, error) { }
+        public WebCallResult(Error? error) : this(null, null, null, null, null, null, null, null, null, null, ResultDataSource.Server, default, error) { }
 
         /// <summary>
         /// Copy the WebCallResult to a new data type
@@ -408,7 +411,7 @@ public WebCallResult(Error? error) : this(null, null, null, null, null, null, nu
         /// <returns></returns>
         public new WebCallResult<K> As<K>([AllowNull] K data)
         {
-            return new WebCallResult<K>(ResponseStatusCode, ResponseHeaders, ResponseTime, ResponseLength, OriginalData, RequestId, RequestUrl, RequestBody, RequestMethod, RequestHeaders, data, Error);
+            return new WebCallResult<K>(ResponseStatusCode, ResponseHeaders, ResponseTime, ResponseLength, OriginalData, RequestId, RequestUrl, RequestBody, RequestMethod, RequestHeaders, DataSource, data, Error);
         }
 
         /// <summary>
@@ -419,7 +422,7 @@ public WebCallResult(Error? error) : this(null, null, null, null, null, null, nu
         /// <returns></returns>
         public new WebCallResult<K> AsError<K>(Error error)
         {
-            return new WebCallResult<K>(ResponseStatusCode, ResponseHeaders, ResponseTime, ResponseLength, OriginalData, RequestId, RequestUrl, RequestBody, RequestMethod, RequestHeaders, default, error);
+            return new WebCallResult<K>(ResponseStatusCode, ResponseHeaders, ResponseTime, ResponseLength, OriginalData, RequestId, RequestUrl, RequestBody, RequestMethod, RequestHeaders, DataSource, default, error);
         }
 
         /// <summary>
@@ -428,9 +431,7 @@ public WebCallResult(Error? error) : this(null, null, null, null, null, null, nu
         /// <returns></returns>
         internal WebCallResult<T> Cached()
         {
-            var result = new WebCallResult<T>(ResponseStatusCode, ResponseHeaders, ResponseTime, ResponseLength, OriginalData, RequestId, RequestUrl, RequestBody, RequestMethod, RequestHeaders, default, Error);
-            result.DataSource = ResultDataSource.Cache;
-            return result;
+            return new WebCallResult<T>(ResponseStatusCode, ResponseHeaders, ResponseTime, ResponseLength, OriginalData, RequestId, RequestUrl, RequestBody, RequestMethod, RequestHeaders, ResultDataSource.Cache, Data, Error);
         }
 
         /// <inheritdoc />