diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdCreativesExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdCreativesExtensions.cs
index 8502411c..6a7874df 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdCreativesExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdCreativesExtensions.cs
@@ -70,7 +70,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 flurlReq.SetQueryParam("adcreative_id", request.AdCreativeId.Value);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             if (request.PageSize.HasValue)
                 flurlReq.SetQueryParam("page_size", request.PageSize.Value);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdGroupsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdGroupsExtensions.cs
index f0c8b370..fd886f8e 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdGroupsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdGroupsExtensions.cs
@@ -70,7 +70,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 flurlReq.SetQueryParam("adgroup_id", request.AdGroupId.Value);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             if (request.PageSize.HasValue)
                 flurlReq.SetQueryParam("page_size", request.PageSize.Value);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdsExtensions.cs
index 1633fa59..ad41e7f9 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAdsExtensions.cs
@@ -70,7 +70,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 flurlReq.SetQueryParam("ad_id", request.AdId.Value);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             if (request.PageSize.HasValue)
                 flurlReq.SetQueryParam("page_size", request.PageSize.Value);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAsyncTasksExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAsyncTasksExtensions.cs
index c81c51e4..eae0a526 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAsyncTasksExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteAsyncTasksExtensions.cs
@@ -48,7 +48,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 .SetQueryParam("access_token", request.AccessToken);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             if (request.PageSize.HasValue)
                 flurlReq.SetQueryParam("page_size", request.PageSize.Value);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteCampaignsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteCampaignsExtensions.cs
index c924b27b..a288cd82 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteCampaignsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteCampaignsExtensions.cs
@@ -70,7 +70,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 flurlReq.SetQueryParam("campaign_id", request.CampaignId.Value);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             if (request.PageSize.HasValue)
                 flurlReq.SetQueryParam("page_size", request.PageSize.Value);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteFundsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteFundsExtensions.cs
index 1526a62a..6f19f6e1 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteFundsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteFundsExtensions.cs
@@ -66,7 +66,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 .SetQueryParam("access_token", request.AccessToken);
 
             if (request.DateRange != null)
-                flurlReq.SetQueryParam("date_range", client.FlurlJsonSerializer.Serialize(request.DateRange));
+                flurlReq.SetQueryParam("date_range", client.JsonSerializer.Serialize(request.DateRange));
 
             if (!string.IsNullOrEmpty(request.TradeType))
                 flurlReq.SetQueryParam("trade_type", request.TradeType);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteImagesExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteImagesExtensions.cs
index 38d65f09..b4ecb6f5 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteImagesExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteImagesExtensions.cs
@@ -75,7 +75,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 flurlReq.SetQueryParam("image_id", request.ImageId);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             if (request.PageSize.HasValue)
                 flurlReq.SetQueryParam("page_size", request.PageSize.Value);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteReportsExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteReportsExtensions.cs
index cd60dddf..38580328 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteReportsExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Extensions/WechatAdsClientExecuteReportsExtensions.cs
@@ -29,7 +29,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 .SetQueryParam("access_token", request.AccessToken);
 
             if (request.DateRange != null)
-                flurlReq.SetQueryParam("date_range", client.FlurlJsonSerializer.Serialize(request.DateRange));
+                flurlReq.SetQueryParam("date_range", client.JsonSerializer.Serialize(request.DateRange));
 
             if (!string.IsNullOrEmpty(request.ReportType))
                 flurlReq.SetQueryParam("report_type", request.ReportType);
@@ -65,7 +65,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
                 .SetQueryParam("level", request.Level);
 
             if (request.Filters != null && request.Filters.Any())
-                flurlReq.SetQueryParam("filtering", client.FlurlJsonSerializer.Serialize(request.Filters));
+                flurlReq.SetQueryParam("filtering", client.JsonSerializer.Serialize(request.Filters));
 
             return await client.SendRequestWithJsonAsync<Models.RealtimeCostGetResponse>(flurlReq, data: request, cancellationToken: cancellationToken);
         }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs
new file mode 100644
index 00000000..9e1f5f76
--- /dev/null
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/Settings/Credentials.cs
@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SKIT.FlurlHttpClient.Wechat.Ads.Settings
+{
+    public class Credentials
+    {
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatAdsClientOptions.AgencyId"/> 的副本。
+        /// </summary>
+        public string AgencyId { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatAdsClientOptions.AgencyAppId"/> 的副本。
+        /// </summary>
+        public string AgencyAppId { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatAdsClientOptions.AgencyApiKey"/> 的副本。
+        /// </summary>
+        public string AgencyApiKey { get; }
+
+        internal Credentials(WechatAdsClientOptions options)
+        {
+            if (options == null) throw new ArgumentNullException(nameof(options));
+
+            AgencyId = options.AgencyId;
+            AgencyAppId = options.AgencyAppId;
+            AgencyApiKey = options.AgencyApiKey;
+        }
+    }
+}
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Ads/WechatAdsClient.cs b/src/SKIT.FlurlHttpClient.Wechat.Ads/WechatAdsClient.cs
index 31f70aa3..79c4cde8 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Ads/WechatAdsClient.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Ads/WechatAdsClient.cs
@@ -18,27 +18,9 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
     public class WechatAdsClient : WechatClientBase
     {
         /// <summary>
-        /// 获取当前客户端使用的微信广告平台服务商 ID。
+        /// 获取当前客户端使用的微信广告平台凭证。
         /// </summary>
-        public string WechatAgencyId { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的微信广告平台服务商 AppId。
-        /// </summary>
-        public string WechatAgencyAppId { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的微信广告平台服务商 ApiKey。
-        /// </summary>
-        internal string WechatAgencyApiKey { get; }
-
-        /// <summary>
-        /// 获取当前客户端使用的 JSON 序列化器。
-        /// </summary>
-        internal ISerializer FlurlJsonSerializer
-        {
-            get { return FlurlClient.Settings?.JsonSerializer ?? new FlurlNewtonsoftJsonSerializer(); }
-        }
+        public Settings.Credentials Credentials { get; }
 
         /// <summary>
         /// 用指定的配置项初始化 <see cref="WechatAdsClient"/> 类的新实例。
@@ -49,9 +31,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Ads
         {
             if (options == null) throw new ArgumentNullException(nameof(options));
 
-            WechatAgencyId = options.AgencyId;
-            WechatAgencyAppId = options.AgencyAppId;
-            WechatAgencyApiKey = options.AgencyApiKey;
+            Credentials = new Settings.Credentials(options);
 
             FlurlClient.BaseUrl = options.Endpoints ?? WechatAdsEndpoints.DEFAULT;
             FlurlClient.WithTimeout(TimeSpan.FromMilliseconds(options.Timeout));