diff --git a/Binance.SDK/Binance.SDK.csproj b/Binance.SDK/Binance.SDK.csproj
new file mode 100644
index 0000000..8ef8970
--- /dev/null
+++ b/Binance.SDK/Binance.SDK.csproj
@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>
diff --git a/Binance.TradeRobot.API.sln b/Binance.TradeRobot.API.sln
index ae57b65..5325efe 100644
--- a/Binance.TradeRobot.API.sln
+++ b/Binance.TradeRobot.API.sln
@@ -9,13 +9,15 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Binance.TradeRobot.Model",
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Binance.TradeRobot.Business", "Binance.TradeRobot.Business\Binance.TradeRobot.Business.csproj", "{74CD58F4-1AA3-4EE9-A68B-386C76CF2125}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Binance.TradeRobot.Common", "Binance.TradeRobot.Common\Binance.TradeRobot.Common.csproj", "{C840DCF2-0E1E-4F9F-9EAA-5A4F80B51BD2}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Binance.TradeRobot.Common", "Binance.TradeRobot.Common\Binance.TradeRobot.Common.csproj", "{C840DCF2-0E1E-4F9F-9EAA-5A4F80B51BD2}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{B55091A9-5FBF-486C-98D6-B7E4AF95D345}"
 	ProjectSection(SolutionItems) = preProject
 		.editorconfig = .editorconfig
 	EndProjectSection
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Binance.SDK", "Binance.SDK\Binance.SDK.csproj", "{8B84B654-82D9-42C0-AF0C-5C78CE916253}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -38,6 +40,10 @@ Global
 		{C840DCF2-0E1E-4F9F-9EAA-5A4F80B51BD2}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{C840DCF2-0E1E-4F9F-9EAA-5A4F80B51BD2}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{C840DCF2-0E1E-4F9F-9EAA-5A4F80B51BD2}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8B84B654-82D9-42C0-AF0C-5C78CE916253}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8B84B654-82D9-42C0-AF0C-5C78CE916253}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8B84B654-82D9-42C0-AF0C-5C78CE916253}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8B84B654-82D9-42C0-AF0C-5C78CE916253}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/Binance.TradeRobot.API/Binance.TradeRobot.API.csproj b/Binance.TradeRobot.API/Binance.TradeRobot.API.csproj
index 6025e8a..f482d46 100644
--- a/Binance.TradeRobot.API/Binance.TradeRobot.API.csproj
+++ b/Binance.TradeRobot.API/Binance.TradeRobot.API.csproj
@@ -22,6 +22,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\Binance.SDK\Binance.SDK.csproj" />
     <ProjectReference Include="..\Binance.TradeRobot.Business\Binance.TradeRobot.Business.csproj" />
     <ProjectReference Include="..\Binance.TradeRobot.Common\Binance.TradeRobot.Common.csproj" />
     <ProjectReference Include="..\Binance.TradeRobot.Model\Binance.TradeRobot.Model.csproj" />
diff --git a/Binance.TradeRobot.Business/Binance.TradeRobot.Business.csproj b/Binance.TradeRobot.Business/Binance.TradeRobot.Business.csproj
index f46ef42..0e37ba7 100644
--- a/Binance.TradeRobot.Business/Binance.TradeRobot.Business.csproj
+++ b/Binance.TradeRobot.Business/Binance.TradeRobot.Business.csproj
@@ -15,6 +15,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\Binance.SDK\Binance.SDK.csproj" />
     <ProjectReference Include="..\Binance.TradeRobot.Common\Binance.TradeRobot.Common.csproj" />
     <ProjectReference Include="..\Binance.TradeRobot.Model\Binance.TradeRobot.Model.csproj" />
   </ItemGroup>
diff --git a/Binance.TradeRobot.Business/UserBusiness.cs b/Binance.TradeRobot.Business/User/UserBusiness.cs
similarity index 100%
rename from Binance.TradeRobot.Business/UserBusiness.cs
rename to Binance.TradeRobot.Business/User/UserBusiness.cs
diff --git a/Binance.TradeRobot.Model/Db/User.cs b/Binance.TradeRobot.Model/Db/User/User.cs
similarity index 100%
rename from Binance.TradeRobot.Model/Db/User.cs
rename to Binance.TradeRobot.Model/Db/User/User.cs
diff --git a/Binance.TradeRobot.Model/Db/UserAccountFundChangeRecord.cs b/Binance.TradeRobot.Model/Db/User/UserAccountFundChangeRecord.cs
similarity index 100%
rename from Binance.TradeRobot.Model/Db/UserAccountFundChangeRecord.cs
rename to Binance.TradeRobot.Model/Db/User/UserAccountFundChangeRecord.cs
diff --git a/Binance.TradeRobot.Model/Db/UserAccountProfitLossRecord.cs b/Binance.TradeRobot.Model/Db/User/UserAccountProfitLossRecord.cs
similarity index 100%
rename from Binance.TradeRobot.Model/Db/UserAccountProfitLossRecord.cs
rename to Binance.TradeRobot.Model/Db/User/UserAccountProfitLossRecord.cs