diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs
index 9e3b0bfba2..f1d014b76a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs
@@ -145,7 +145,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
             ActionApiDescriptionModel.Create(
                 uniqueMethodName,
                 method,
-                apiDescription.RelativePath,
+                apiDescription.RelativePath!,
                 apiDescription.HttpMethod,
                 GetSupportedVersions(controllerType, method, setting),
                 allowAnonymous,
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs
index b912d3905a..d4fd27d889 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs
@@ -32,7 +32,7 @@ public class ServiceProxyGenerationModel
 
     public ProxyScriptingModel CreateOptions()
     {
-        var options = new ProxyScriptingModel(Type, UseCache);
+        var options = new ProxyScriptingModel(Type!, UseCache);
 
         if (!Modules.IsNullOrEmpty())
         {
diff --git a/framework/src/Volo.Abp.Http.Abstractions/Volo.Abp.Http.Abstractions.csproj b/framework/src/Volo.Abp.Http.Abstractions/Volo.Abp.Http.Abstractions.csproj
index 332c803147..adbc783c15 100644
--- a/framework/src/Volo.Abp.Http.Abstractions/Volo.Abp.Http.Abstractions.csproj
+++ b/framework/src/Volo.Abp.Http.Abstractions/Volo.Abp.Http.Abstractions.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Http.Abstractions</AssemblyName>
     <PackageId>Volo.Abp.Http.Abstractions</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http.Abstractions/Volo/Abp/Http/ClientProxyExceptionEventData.cs b/framework/src/Volo.Abp.Http.Abstractions/Volo/Abp/Http/ClientProxyExceptionEventData.cs
index 1bc17c7b65..029556c00e 100644
--- a/framework/src/Volo.Abp.Http.Abstractions/Volo/Abp/Http/ClientProxyExceptionEventData.cs
+++ b/framework/src/Volo.Abp.Http.Abstractions/Volo/Abp/Http/ClientProxyExceptionEventData.cs
@@ -4,5 +4,5 @@ public class ClientProxyExceptionEventData
 {
     public int? StatusCode { get; set; }
 
-    public string ReasonPhrase { get; set; }
+    public string? ReasonPhrase { get; set; }
 }
diff --git a/framework/src/Volo.Abp.Http.Client.Dapr/Volo.Abp.Http.Client.Dapr.csproj b/framework/src/Volo.Abp.Http.Client.Dapr/Volo.Abp.Http.Client.Dapr.csproj
index 0d22e68b97..1fd0b7b07b 100644
--- a/framework/src/Volo.Abp.Http.Client.Dapr/Volo.Abp.Http.Client.Dapr.csproj
+++ b/framework/src/Volo.Abp.Http.Client.Dapr/Volo.Abp.Http.Client.Dapr.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <RootNamespace />
     </PropertyGroup>
 
diff --git a/framework/src/Volo.Abp.Http.Client.Dapr/Volo/Abp/Http/Client/Dapr/AbpInvocationHandler.cs b/framework/src/Volo.Abp.Http.Client.Dapr/Volo/Abp/Http/Client/Dapr/AbpInvocationHandler.cs
index 9ebfb5665d..4a17c3b67a 100644
--- a/framework/src/Volo.Abp.Http.Client.Dapr/Volo/Abp/Http/Client/Dapr/AbpInvocationHandler.cs
+++ b/framework/src/Volo.Abp.Http.Client.Dapr/Volo/Abp/Http/Client/Dapr/AbpInvocationHandler.cs
@@ -12,7 +12,7 @@ public class AbpInvocationHandler : InvocationHandler, ITransientDependency
     {
         if (!daprOptions.Value.HttpEndpoint.IsNullOrWhiteSpace())
         {
-            DaprEndpoint = daprOptions.Value.HttpEndpoint;
+            DaprEndpoint = daprOptions.Value.HttpEndpoint!;
         }
     }
 }
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo.Abp.Http.Client.IdentityModel.MauiBlazor.csproj b/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo.Abp.Http.Client.IdentityModel.MauiBlazor.csproj
index 671fd3db2d..4a92cc975d 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo.Abp.Http.Client.IdentityModel.MauiBlazor.csproj
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo.Abp.Http.Client.IdentityModel.MauiBlazor.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <PackageId>Volo.Abp.Http.Client.IdentityModel.MauiBlazor</PackageId>
         <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
         <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo/Abp/Http/Client/IdentityModel/MauiBlazor/MauiBlazorAbpAccessTokenProvider.cs b/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo/Abp/Http/Client/IdentityModel/MauiBlazor/MauiBlazorAbpAccessTokenProvider.cs
index 8afbcbafed..3f923aa9bb 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo/Abp/Http/Client/IdentityModel/MauiBlazor/MauiBlazorAbpAccessTokenProvider.cs
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel.MauiBlazor/Volo/Abp/Http/Client/IdentityModel/MauiBlazor/MauiBlazorAbpAccessTokenProvider.cs
@@ -7,7 +7,7 @@ namespace Volo.Abp.Http.Client.IdentityModel.MauiBlazor;
 [Dependency(ReplaceServices = true)]
 public class MauiBlazorAbpAccessTokenProvider : IAbpAccessTokenProvider, ITransientDependency
 {
-    public virtual Task<string> GetTokenAsync()
+    public virtual Task<string?> GetTokenAsync()
     {
         return Task.FromResult(null as string);
     }
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo.Abp.Http.Client.IdentityModel.Web.csproj b/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo.Abp.Http.Client.IdentityModel.Web.csproj
index 4fc1525e59..05d1a14ef8 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo.Abp.Http.Client.IdentityModel.Web.csproj
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo.Abp.Http.Client.IdentityModel.Web.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Http.Client.IdentityModel.Web</AssemblyName>
     <PackageId>Volo.Abp.Http.Client.IdentityModel.Web</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo/Abp/Http/Client/IdentityModel/Web/HttpContextAbpAccessTokenProvider.cs b/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo/Abp/Http/Client/IdentityModel/Web/HttpContextAbpAccessTokenProvider.cs
index 97d88bd3b0..5044513438 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo/Abp/Http/Client/IdentityModel/Web/HttpContextAbpAccessTokenProvider.cs
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel.Web/Volo/Abp/Http/Client/IdentityModel/Web/HttpContextAbpAccessTokenProvider.cs
@@ -16,7 +16,7 @@ public class HttpContextAbpAccessTokenProvider : IAbpAccessTokenProvider, ITrans
         HttpContextAccessor = httpContextAccessor;
     }
 
-    public virtual async Task<string> GetTokenAsync()
+    public virtual async Task<string?> GetTokenAsync()
     {
         var httpContext = HttpContextAccessor?.HttpContext;
         if (httpContext == null)
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo.Abp.Http.Client.IdentityModel.WebAssembly.csproj b/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo.Abp.Http.Client.IdentityModel.WebAssembly.csproj
index e98f5d92ff..42d60909bc 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo.Abp.Http.Client.IdentityModel.WebAssembly.csproj
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo.Abp.Http.Client.IdentityModel.WebAssembly.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <AssemblyName>Volo.Abp.Http.Client.IdentityModel.WebAssembly</AssemblyName>
         <PackageId>Volo.Abp.Http.Client.IdentityModel.WebAssembly</PackageId>
         <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo/Abp/Http/Client/IdentityModel/WebAssembly/WebAssemblyAbpAccessTokenProvider.cs b/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo/Abp/Http/Client/IdentityModel/WebAssembly/WebAssemblyAbpAccessTokenProvider.cs
index d0a68cdb7c..137787820b 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo/Abp/Http/Client/IdentityModel/WebAssembly/WebAssemblyAbpAccessTokenProvider.cs
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel.WebAssembly/Volo/Abp/Http/Client/IdentityModel/WebAssembly/WebAssemblyAbpAccessTokenProvider.cs
@@ -8,14 +8,14 @@ namespace Volo.Abp.Http.Client.IdentityModel.WebAssembly;
 [Dependency(ReplaceServices = true)]
 public class WebAssemblyAbpAccessTokenProvider : IAbpAccessTokenProvider, ITransientDependency
 {
-    protected IAccessTokenProvider AccessTokenProvider { get; }
+    protected IAccessTokenProvider? AccessTokenProvider { get; }
 
     public WebAssemblyAbpAccessTokenProvider(IAccessTokenProvider accessTokenProvider)
     {
         AccessTokenProvider = accessTokenProvider;
     }
 
-    public virtual async Task<string> GetTokenAsync()
+    public virtual async Task<string?> GetTokenAsync()
     {
         if (AccessTokenProvider == null)
         {
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo.Abp.Http.Client.IdentityModel.csproj b/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo.Abp.Http.Client.IdentityModel.csproj
index 083e987d49..3e791a1e69 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo.Abp.Http.Client.IdentityModel.csproj
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo.Abp.Http.Client.IdentityModel.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Http.Client.IdentityModel</AssemblyName>
     <PackageId>Volo.Abp.Http.Client.IdentityModel</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo/Abp/Http/Client/RemoteServiceConfigurationExtensions.cs b/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo/Abp/Http/Client/RemoteServiceConfigurationExtensions.cs
index 417875619b..58c4b71078 100644
--- a/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo/Abp/Http/Client/RemoteServiceConfigurationExtensions.cs
+++ b/framework/src/Volo.Abp.Http.Client.IdentityModel/Volo/Abp/Http/Client/RemoteServiceConfigurationExtensions.cs
@@ -8,8 +8,7 @@ public static class RemoteServiceConfigurationExtensions
     public const string IdentityClientName = "IdentityClient";
     public const string UseCurrentAccessTokenName = "UseCurrentAccessToken";
 
-    [CanBeNull]
-    public static string GetIdentityClient([NotNull] this RemoteServiceConfiguration configuration)
+    public static string? GetIdentityClient([NotNull] this RemoteServiceConfiguration configuration)
     {
         Check.NotNullOrEmpty(configuration, nameof(configuration));
 
diff --git a/framework/src/Volo.Abp.Http.Client.Web/Volo.Abp.Http.Client.Web.csproj b/framework/src/Volo.Abp.Http.Client.Web/Volo.Abp.Http.Client.Web.csproj
index 68bbbd1157..63da778ecd 100644
--- a/framework/src/Volo.Abp.Http.Client.Web/Volo.Abp.Http.Client.Web.csproj
+++ b/framework/src/Volo.Abp.Http.Client.Web/Volo.Abp.Http.Client.Web.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <AssemblyName>Volo.Abp.Http.Client.Web</AssemblyName>
         <PackageId>Volo.Abp.Http.Client.Web</PackageId>
         <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http.Client.Web/Volo/Abp/Http/Client/Web/Conventions/AbpHttpClientProxyServiceConvention.cs b/framework/src/Volo.Abp.Http.Client.Web/Volo/Abp/Http/Client/Web/Conventions/AbpHttpClientProxyServiceConvention.cs
index 49080939c2..a7a2aad343 100644
--- a/framework/src/Volo.Abp.Http.Client.Web/Volo/Abp/Http/Client/Web/Conventions/AbpHttpClientProxyServiceConvention.cs
+++ b/framework/src/Volo.Abp.Http.Client.Web/Volo/Abp/Http/Client/Web/Conventions/AbpHttpClientProxyServiceConvention.cs
@@ -69,7 +69,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
             if (controllerApiDescription != null &&
                 !controllerApiDescription.ControllerGroupName.IsNullOrWhiteSpace())
             {
-                controller.ControllerName = controllerApiDescription.ControllerGroupName;
+                controller.ControllerName = controllerApiDescription.ControllerGroupName!;
             }
 
             ConfigureClientProxySelector(controller);
@@ -115,7 +115,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
         {
             var selector = controller.Selectors.FirstOrDefault();
             selector?.EndpointMetadata.Add(new AreaAttribute(moduleApiDescription.RootPath));
-            controller.RouteValues.Add(new KeyValuePair<string, string>("area", moduleApiDescription.RootPath));
+            controller.RouteValues.Add(new KeyValuePair<string, string?>("area", moduleApiDescription.RootPath));
         }
 
         var controllerType = controller.ControllerType.AsType();
@@ -163,7 +163,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
                 var abpServiceSelectorModel = new SelectorModel
                 {
                     AttributeRouteModel = new AttributeRouteModel(new RouteAttribute(template: actionApiDescriptionModel.Url)),
-                    ActionConstraints = { new HttpMethodActionConstraint(new[] { actionApiDescriptionModel.HttpMethod }) }
+                    ActionConstraints = { new HttpMethodActionConstraint(new[] { actionApiDescriptionModel.HttpMethod! }) }
                 };
 
                 action.Selectors.Add(abpServiceSelectorModel);
@@ -190,7 +190,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
 
                     if (!selector.ActionConstraints.OfType<HttpMethodActionConstraint>().Any())
                     {
-                        selector.ActionConstraints.Add(new HttpMethodActionConstraint(new[] { httpMethod }));
+                        selector.ActionConstraints.Add(new HttpMethodActionConstraint(new[] { httpMethod! }));
                     }
                 }
             }
@@ -226,7 +226,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
         }
     }
 
-    protected virtual ModuleApiDescriptionModel FindModuleApiDescriptionModel(ControllerModel controller)
+    protected virtual ModuleApiDescriptionModel? FindModuleApiDescriptionModel(ControllerModel controller)
     {
         var appServiceType = FindAppServiceInterfaceType(controller);
         if (appServiceType == null)
@@ -246,7 +246,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
         return null;
     }
 
-    protected virtual ControllerApiDescriptionModel FindControllerApiDescriptionModel(ControllerModel controller)
+    protected virtual ControllerApiDescriptionModel? FindControllerApiDescriptionModel(ControllerModel controller)
     {
         var appServiceType = FindAppServiceInterfaceType(controller);
         if (appServiceType == null)
@@ -266,7 +266,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
         return null;
     }
 
-    protected virtual ActionApiDescriptionModel FindActionApiDescriptionModel(ControllerModel controller, ActionModel action)
+    protected virtual ActionApiDescriptionModel? FindActionApiDescriptionModel(ControllerModel controller, ActionModel action)
     {
         var appServiceType = FindAppServiceInterfaceType(controller);
         if (appServiceType == null)
@@ -285,7 +285,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
             return null;
         }
 
-        if (actionApiDescriptionModel.ImplementFrom.StartsWith("Volo.Abp.Application.Services"))
+        if (actionApiDescriptionModel.ImplementFrom!.StartsWith("Volo.Abp.Application.Services"))
         {
             return actionApiDescriptionModel;
         }
@@ -298,7 +298,7 @@ public class AbpHttpClientProxyServiceConvention : AbpServiceConvention
         return null;
     }
 
-    protected virtual Type FindAppServiceInterfaceType(ControllerModel controller)
+    protected virtual Type? FindAppServiceInterfaceType(ControllerModel controller)
     {
         return controller.ControllerType.GetInterfaces()
             .FirstOrDefault(type => !type.IsGenericType &&
diff --git a/framework/src/Volo.Abp.Http.Client/Microsoft/Extensions/DependencyInjection/ServiceCollectionHttpClientProxyExtensions.cs b/framework/src/Volo.Abp.Http.Client/Microsoft/Extensions/DependencyInjection/ServiceCollectionHttpClientProxyExtensions.cs
index 3f71924f9d..ab8d5974a8 100644
--- a/framework/src/Volo.Abp.Http.Client/Microsoft/Extensions/DependencyInjection/ServiceCollectionHttpClientProxyExtensions.cs
+++ b/framework/src/Volo.Abp.Http.Client/Microsoft/Extensions/DependencyInjection/ServiceCollectionHttpClientProxyExtensions.cs
@@ -191,7 +191,7 @@ public static class ServiceCollectionHttpClientProxyExtensions
                 return Activator.CreateInstance(
                     typeof(HttpClientProxy<>).MakeGenericType(type),
                     service
-                );
+                )!;
             });
 
         return services;
diff --git a/framework/src/Volo.Abp.Http.Client/Volo.Abp.Http.Client.csproj b/framework/src/Volo.Abp.Http.Client/Volo.Abp.Http.Client.csproj
index 0b4e3ad76f..0b05d8b1c7 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo.Abp.Http.Client.csproj
+++ b/framework/src/Volo.Abp.Http.Client/Volo.Abp.Http.Client.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Http.Client</AssemblyName>
     <PackageId>Volo.Abp.Http.Client</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/IAbpAccessTokenProvider.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/IAbpAccessTokenProvider.cs
index a4e9e650e3..ceadc832ec 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/IAbpAccessTokenProvider.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/IAbpAccessTokenProvider.cs
@@ -4,5 +4,5 @@ namespace Volo.Abp.Http.Client.Authentication;
 
 public interface IAbpAccessTokenProvider
 {
-    Task<string> GetTokenAsync();
+    Task<string?> GetTokenAsync();
 }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/NullAbpAccessTokenProvider.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/NullAbpAccessTokenProvider.cs
index 6bd7e6344b..47ae349bf0 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/NullAbpAccessTokenProvider.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Authentication/NullAbpAccessTokenProvider.cs
@@ -5,7 +5,7 @@ namespace Volo.Abp.Http.Client.Authentication;
 
 public class NullAbpAccessTokenProvider : IAbpAccessTokenProvider, ITransientDependency
 {
-    public Task<string> GetTokenAsync()
+    public Task<string?> GetTokenAsync()
     {
         return Task.FromResult(null as string);
     }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyApiDescriptionFinder.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyApiDescriptionFinder.cs
index f7b9b838b5..e8da52f3b1 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyApiDescriptionFinder.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyApiDescriptionFinder.cs
@@ -17,7 +17,7 @@ public class ClientProxyApiDescriptionFinder : IClientProxyApiDescriptionFinder,
     protected IVirtualFileProvider VirtualFileProvider { get; }
     protected IJsonSerializer JsonSerializer { get; }
     protected Dictionary<string, ActionApiDescriptionModel> ActionApiDescriptionModels { get; }
-    protected ApplicationApiDescriptionModel ApplicationApiDescriptionModel { get; set; }
+    protected ApplicationApiDescriptionModel ApplicationApiDescriptionModel { get; set; } = default!;
 
     public ClientProxyApiDescriptionFinder(
         IVirtualFileProvider virtualFileProvider,
@@ -30,7 +30,7 @@ public class ClientProxyApiDescriptionFinder : IClientProxyApiDescriptionFinder,
         Initialize();
     }
 
-    public ActionApiDescriptionModel FindAction(string methodName)
+    public ActionApiDescriptionModel? FindAction(string methodName)
     {
         return ActionApiDescriptionModels.ContainsKey(methodName) ? ActionApiDescriptionModels[methodName] : null;
     }
@@ -113,7 +113,7 @@ public class ClientProxyApiDescriptionFinder : IClientProxyApiDescriptionFinder,
             return rootPath + physicalDirectoryInfo.Name.EnsureStartsWith('/');
         }
 
-        return fileInfo.PhysicalPath;
+        return fileInfo.PhysicalPath!;
     }
     
     private string GetProxyFileInfoPath(string rootPath, IFileInfo fileInfo)
@@ -123,6 +123,6 @@ public class ClientProxyApiDescriptionFinder : IClientProxyApiDescriptionFinder,
             return rootPath + physicalFileInfo.Name.EnsureStartsWith('/');
         }
 
-        return fileInfo.GetVirtualOrPhysicalPathOrNull();
+        return fileInfo.GetVirtualOrPhysicalPathOrNull()!;
     }
 }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyBase.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyBase.cs
index 5c1d893bfd..8dee0fcc3e 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyBase.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyBase.cs
@@ -25,7 +25,7 @@ namespace Volo.Abp.Http.Client.ClientProxying;
 
 public class ClientProxyBase<TService> : ITransientDependency
 {
-    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }
+    public IAbpLazyServiceProvider LazyServiceProvider { get; set; } = default!;
 
     protected IClientProxyApiDescriptionFinder ClientProxyApiDescriptionFinder => LazyServiceProvider.LazyGetRequiredService<IClientProxyApiDescriptionFinder>();
     protected ICancellationTokenProvider CancellationTokenProvider => LazyServiceProvider.LazyGetRequiredService<ICancellationTokenProvider>();
@@ -42,17 +42,17 @@ public class ClientProxyBase<TService> : ITransientDependency
     protected ICurrentApiVersionInfo CurrentApiVersionInfo => LazyServiceProvider.LazyGetRequiredService<ICurrentApiVersionInfo>();
     protected ILocalEventBus LocalEventBus => LazyServiceProvider.LazyGetRequiredService<ILocalEventBus>();
 
-    protected virtual async Task RequestAsync(string methodName, ClientProxyRequestTypeValue arguments = null)
+    protected virtual async Task RequestAsync(string methodName, ClientProxyRequestTypeValue? arguments = null)
     {
         await RequestAsync(BuildHttpProxyClientProxyContext(methodName, arguments));
     }
 
-    protected virtual async Task<T> RequestAsync<T>(string methodName, ClientProxyRequestTypeValue arguments = null)
+    protected virtual async Task<T> RequestAsync<T>(string methodName, ClientProxyRequestTypeValue? arguments = null)
     {
         return await RequestAsync<T>(BuildHttpProxyClientProxyContext(methodName, arguments));
     }
 
-    protected virtual ClientProxyRequestContext BuildHttpProxyClientProxyContext(string methodName, ClientProxyRequestTypeValue arguments = null)
+    protected virtual ClientProxyRequestContext BuildHttpProxyClientProxyContext(string methodName, ClientProxyRequestTypeValue? arguments = null)
     {
         if (arguments == null)
         {
@@ -67,7 +67,7 @@ public class ClientProxyBase<TService> : ITransientDependency
         }
 
         var actionArguments = action.Parameters.GroupBy(x => x.NameOnMethod).ToList();
-        if (action.SupportedVersions.Any())
+        if (action.SupportedVersions != null && action.SupportedVersions.Any())
         {
             //TODO: make names configurable
             actionArguments.RemoveAll(x => x.Key == "api-version" || x.Key == "apiVersion");
@@ -107,7 +107,7 @@ public class ClientProxyBase<TService> : ITransientDependency
 
         if (stringContent.IsNullOrWhiteSpace())
         {
-            return default;
+            return default!;
         }
 
         return JsonSerializer.Deserialize<T>(stringContent);
@@ -177,7 +177,7 @@ public class ClientProxyBase<TService> : ITransientDependency
         var versionParam = requestContext.Action.Parameters.FirstOrDefault(p => p.Name == "apiVersion" && p.BindingSourceId == ParameterBindingSources.Path) ??
                            requestContext.Action.Parameters.FirstOrDefault(p => p.Name == "api-version" && p.BindingSourceId == ParameterBindingSources.Query);
 
-        return new ApiVersionInfo(versionParam?.BindingSourceId, apiVersion);
+        return new ApiVersionInfo(versionParam?.BindingSourceId!, apiVersion);
     }
 
     protected virtual async Task<string> GetUrlWithParametersAsync(ClientProxyRequestContext requestContext, ApiVersionInfo apiVersion)
@@ -185,7 +185,7 @@ public class ClientProxyBase<TService> : ITransientDependency
         return await ClientProxyUrlBuilder.GenerateUrlWithParametersAsync(requestContext.Action, requestContext.Arguments, apiVersion);
     }
 
-    protected virtual async Task<HttpContent> GetHttpContentAsync(ClientProxyRequestContext requestContext, ApiVersionInfo apiVersion)
+    protected virtual async Task<HttpContent?> GetHttpContentAsync(ClientProxyRequestContext requestContext, ApiVersionInfo apiVersion)
     {
         return await ClientProxyRequestPayloadBuilder.BuildContentAsync(requestContext.Action, requestContext.Arguments, JsonSerializer, apiVersion);
     }
@@ -199,15 +199,15 @@ public class ClientProxyBase<TService> : ITransientDependency
             return configuredVersion ?? "1.0";
         }
 
-        if (requestContext.Action.SupportedVersions.Contains(configuredVersion))
+        if (requestContext.Action.SupportedVersions!.Contains(configuredVersion!))
         {
-            return configuredVersion;
+            return configuredVersion!;
         }
 
         return requestContext.Action.SupportedVersions.Last(); //TODO: Ensure to get the latest version!
     }
 
-    protected virtual async Task<string> GetConfiguredApiVersionAsync(ClientProxyRequestContext requestContext)
+    protected virtual async Task<string?> GetConfiguredApiVersionAsync(ClientProxyRequestContext requestContext)
     {
         var clientConfig = ClientOptions.Value.HttpClientProxies.GetOrDefault(requestContext.ServiceType)
                            ?? throw new AbpException($"Could not get DynamicHttpClientProxyConfig for {requestContext.ServiceType.FullName}.");
@@ -220,8 +220,8 @@ public class ClientProxyBase<TService> : ITransientDependency
     {
         await LocalEventBus.PublishAsync(new ClientProxyExceptionEventData()
         {
-            StatusCode = (int?)response?.StatusCode,
-            ReasonPhrase = response?.ReasonPhrase
+            StatusCode = (int?)response.StatusCode,
+            ReasonPhrase = response.ReasonPhrase
         });
 
         if (response.Headers.Contains(AbpHttpConsts.AbpErrorFormat))
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyRequestPayloadBuilder.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyRequestPayloadBuilder.cs
index abbbb8b6f1..d7755a1ac9 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyRequestPayloadBuilder.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyRequestPayloadBuilder.cs
@@ -40,8 +40,7 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
         HttpClientProxyingOptions = httpClientProxyingOptions.Value;
     }
 
-    [CanBeNull]
-    public virtual async Task<HttpContent> BuildContentAsync(ActionApiDescriptionModel action, IReadOnlyDictionary<string, object> methodArguments, IJsonSerializer jsonSerializer, ApiVersionInfo apiVersion)
+    public virtual async Task<HttpContent?> BuildContentAsync(ActionApiDescriptionModel action, IReadOnlyDictionary<string, object> methodArguments, IJsonSerializer jsonSerializer, ApiVersionInfo apiVersion)
     {
         var body = await GenerateBodyAsync(action, methodArguments, jsonSerializer);
         if (body != null)
@@ -54,7 +53,7 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
         return body;
     }
 
-    protected virtual Task<HttpContent> GenerateBodyAsync(ActionApiDescriptionModel action, IReadOnlyDictionary<string, object> methodArguments, IJsonSerializer jsonSerializer)
+    protected virtual Task<HttpContent?> GenerateBodyAsync(ActionApiDescriptionModel action, IReadOnlyDictionary<string, object> methodArguments, IJsonSerializer jsonSerializer)
     {
         var parameters = action
             .Parameters
@@ -63,7 +62,7 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
 
         if (parameters.Length <= 0)
         {
-            return Task.FromResult<HttpContent>(null);
+            return Task.FromResult<HttpContent?>(null);
         }
 
         if (parameters.Length > 1)
@@ -76,13 +75,13 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
         var value = HttpActionParameterHelper.FindParameterValue(methodArguments, parameters[0]);
         if (value == null)
         {
-            return Task.FromResult<HttpContent>(null);
+            return Task.FromResult<HttpContent?>(null);
         }
 
-        return Task.FromResult<HttpContent>(new StringContent(jsonSerializer.Serialize(value), Encoding.UTF8, MimeTypes.Application.Json));
+        return Task.FromResult<HttpContent?>(new StringContent(jsonSerializer.Serialize(value), Encoding.UTF8, MimeTypes.Application.Json));
     }
 
-    protected virtual async Task<HttpContent> GenerateFormPostDataAsync(ActionApiDescriptionModel action, IReadOnlyDictionary<string, object> methodArguments)
+    protected virtual async Task<HttpContent?> GenerateFormPostDataAsync(ActionApiDescriptionModel action, IReadOnlyDictionary<string, object> methodArguments)
     {
         var parameters = action
             .Parameters
@@ -108,7 +107,7 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
             {
                 using (var scope = ServiceScopeFactory.CreateScope())
                 {
-                    var formDataContents = await (Task<List<KeyValuePair<string, HttpContent>>>)CallObjectToFormDataAsyncMethod
+                    var formDataContents = await (Task<List<KeyValuePair<string, HttpContent>>?>)CallObjectToFormDataAsyncMethod
                         .MakeGenericMethod(value.GetType())
                         .Invoke(this, new object[]
                         {
@@ -116,7 +115,7 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
                             action,
                             parameter,
                             value
-                        });
+                        })!;
 
                     if (formDataContents != null)
                     {
@@ -158,12 +157,12 @@ public class ClientProxyRequestPayloadBuilder : ITransientDependency
             {
                 foreach (var item in (IEnumerable) value)
                 {
-                    formData.Add(new StringContent(item.ToString(), Encoding.UTF8), parameter.Name);
+                    formData.Add(new StringContent(item.ToString()!, Encoding.UTF8), parameter.Name);
                 }
             }
             else
             {
-                formData.Add(new StringContent(value.ToString(), Encoding.UTF8), parameter.Name);
+                formData.Add(new StringContent(value.ToString()!, Encoding.UTF8), parameter.Name);
             }
         }
 
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyUrlBuilder.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyUrlBuilder.cs
index 63ddd75510..65703dc56b 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyUrlBuilder.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ClientProxyUrlBuilder.cs
@@ -100,15 +100,15 @@ public class ClientProxyUrlBuilder : ITransientDependency
                 {
                     using (var scope = ServiceScopeFactory.CreateScope())
                     {
-                        var path = await (Task<string>)CallObjectToPathAsyncMethod
+                        var path = await (Task<string?>)CallObjectToPathAsyncMethod
                             .MakeGenericMethod(value.GetType())
-                            .Invoke(this, new object[]
+                            .Invoke(this, new object?[]
                             {
                                 scope.ServiceProvider.GetRequiredService(HttpClientProxyingOptions.PathConverts[value.GetType()]),
                                 action,
                                 pathParameter,
                                 value
-                            });
+                            })!;
 
                         if (path != null)
                         {
@@ -143,7 +143,7 @@ public class ClientProxyUrlBuilder : ITransientDependency
             {
                 using (var scope = ServiceScopeFactory.CreateScope())
                 {
-                    var queryString = await (Task<string>)CallObjectToQueryStringAsyncMethod
+                    var queryString = await (Task<string?>)CallObjectToQueryStringAsyncMethod
                         .MakeGenericMethod(value.GetType())
                         .Invoke(this, new object[]
                         {
@@ -151,7 +151,7 @@ public class ClientProxyUrlBuilder : ITransientDependency
                             action,
                             queryStringParameter,
                             value
-                        });
+                        })!;
 
                     if (queryString != null)
                     {
@@ -218,11 +218,11 @@ public class ClientProxyUrlBuilder : ITransientDependency
         return true;
     }
 
-    protected virtual Task<string> ConvertValueToStringAsync([CanBeNull] object value)
+    protected virtual Task<string?> ConvertValueToStringAsync(object? value)
     {
         if (value is DateTime dateTimeValue)
         {
-            return Task.FromResult(dateTimeValue.ToUniversalTime().ToString("O"));
+            return Task.FromResult(dateTimeValue.ToUniversalTime().ToString("O"))!;
         }
 
         return Task.FromResult(value?.ToString());
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/CurrentApiVersionInfo.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/CurrentApiVersionInfo.cs
index f56e9e893a..7c0bac4c81 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/CurrentApiVersionInfo.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/CurrentApiVersionInfo.cs
@@ -6,11 +6,11 @@ namespace Volo.Abp.Http.Client.ClientProxying;
 
 public class CurrentApiVersionInfo : ICurrentApiVersionInfo, ISingletonDependency
 {
-    public ApiVersionInfo ApiVersionInfo => _currentApiVersionInfo.Value;
+    public ApiVersionInfo? ApiVersionInfo => _currentApiVersionInfo.Value;
 
-    private readonly AsyncLocal<ApiVersionInfo> _currentApiVersionInfo = new AsyncLocal<ApiVersionInfo>();
+    private readonly AsyncLocal<ApiVersionInfo?> _currentApiVersionInfo = new AsyncLocal<ApiVersionInfo?>();
 
-    public virtual IDisposable Change(ApiVersionInfo apiVersionInfo)
+    public virtual IDisposable Change(ApiVersionInfo? apiVersionInfo)
     {
         var parent = ApiVersionInfo;
         _currentApiVersionInfo.Value = apiVersionInfo;
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/IClientProxyApiDescriptionFinder.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/IClientProxyApiDescriptionFinder.cs
index baf1d6facf..4394b92bcc 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/IClientProxyApiDescriptionFinder.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/IClientProxyApiDescriptionFinder.cs
@@ -4,7 +4,7 @@ namespace Volo.Abp.Http.Client.ClientProxying;
 
 public interface IClientProxyApiDescriptionFinder
 {
-    ActionApiDescriptionModel FindAction(string methodName);
+    ActionApiDescriptionModel? FindAction(string methodName);
 
     ApplicationApiDescriptionModel GetApiDescription();
 }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ICurrentApiVersionInfo.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ICurrentApiVersionInfo.cs
index 9a8fe264bf..e5ac53fafe 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ICurrentApiVersionInfo.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/ClientProxying/ICurrentApiVersionInfo.cs
@@ -4,7 +4,7 @@ namespace Volo.Abp.Http.Client.ClientProxying;
 
 public interface ICurrentApiVersionInfo
 {
-    ApiVersionInfo ApiVersionInfo { get; }
+    ApiVersionInfo? ApiVersionInfo { get; }
 
-    IDisposable Change(ApiVersionInfo apiVersionInfo);
+    IDisposable Change(ApiVersionInfo? apiVersionInfo);
 }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/ApiDescriptionFinder.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/ApiDescriptionFinder.cs
index f01ada7127..44f005add9 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/ApiDescriptionFinder.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/ApiDescriptionFinder.cs
@@ -118,7 +118,7 @@ public class ApiDescriptionFinder : IApiDescriptionFinder, ITransientDependency
 
         var content = await response.Content.ReadAsStringAsync();
 
-        var result = JsonSerializer.Deserialize<ApplicationApiDescriptionModel>(content, DeserializeOptions);
+        var result = JsonSerializer.Deserialize<ApplicationApiDescriptionModel>(content, DeserializeOptions)!;
 
         return result;
     }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/DynamicHttpProxyInterceptor.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/DynamicHttpProxyInterceptor.cs
index 9c30c84496..0f5a9e3642 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/DynamicHttpProxyInterceptor.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/DynamicProxying/DynamicHttpProxyInterceptor.cs
@@ -66,7 +66,7 @@ public class DynamicHttpProxyInterceptor<TService> : AbpInterceptor, ITransientD
             var returnType = invocation.Method.ReturnType.GenericTypeArguments[0];
             var result = (Task)CallRequestAsyncMethod
                 .MakeGenericMethod(returnType)
-                .Invoke(this, new object[] { context });
+                .Invoke(this, new object[] { context })!;
 
             invocation.ReturnValue = await GetResultAsync(result, returnType);
         }
@@ -99,6 +99,6 @@ public class DynamicHttpProxyInterceptor<TService> : AbpInterceptor, ITransientD
             .MakeGenericType(resultType)
             .GetProperty(nameof(Task<object>.Result), BindingFlags.Instance | BindingFlags.Public);
         Check.NotNull(resultProperty, nameof(resultProperty));
-        return resultProperty.GetValue(task);
+        return resultProperty!.GetValue(task)!;
     }
 }
diff --git a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Proxying/HttpActionParameterHelper.cs b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Proxying/HttpActionParameterHelper.cs
index d5d5c4d971..f9fc79b81f 100644
--- a/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Proxying/HttpActionParameterHelper.cs
+++ b/framework/src/Volo.Abp.Http.Client/Volo/Abp/Http/Client/Proxying/HttpActionParameterHelper.cs
@@ -6,7 +6,7 @@ namespace Volo.Abp.Http.Client.Proxying;
 
 internal static class HttpActionParameterHelper
 {
-    public static object FindParameterValue(IReadOnlyDictionary<string, object> methodArguments, ParameterApiDescriptionModel apiParameter)
+    public static object? FindParameterValue(IReadOnlyDictionary<string, object> methodArguments, ParameterApiDescriptionModel apiParameter)
     {
         var value = methodArguments.GetOrDefault(apiParameter.NameOnMethod);
         if (value == null)
diff --git a/framework/src/Volo.Abp.Http/Volo.Abp.Http.csproj b/framework/src/Volo.Abp.Http/Volo.Abp.Http.csproj
index 3b029e3b9d..11cdaffe09 100644
--- a/framework/src/Volo.Abp.Http/Volo.Abp.Http.csproj
+++ b/framework/src/Volo.Abp.Http/Volo.Abp.Http.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Http</AssemblyName>
     <PackageId>Volo.Abp.Http</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/HttpMethodHelper.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/HttpMethodHelper.cs
index 603b6797c3..78ee75e901 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/HttpMethodHelper.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/HttpMethodHelper.cs
@@ -43,12 +43,12 @@ public static class HttpMethodHelper
             return methodName;
         }
 
-        return methodName.RemovePreFix(prefixes);
+        return methodName.RemovePreFix(prefixes!);
     }
 
-    public static HttpMethod ConvertToHttpMethod(string httpMethod)
+    public static HttpMethod ConvertToHttpMethod(string? httpMethod)
     {
-        switch (httpMethod.ToUpperInvariant())
+        switch (httpMethod?.ToUpperInvariant())
         {
             case "GET":
                 return HttpMethod.Get;
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ActionApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ActionApiDescriptionModel.cs
index 9e1d208ddf..890637d801 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ActionApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ActionApiDescriptionModel.cs
@@ -10,32 +10,32 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class ActionApiDescriptionModel
 {
-    public string UniqueName { get; set; }
+    public string UniqueName { get; set; } = default!;
 
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public string HttpMethod { get; set; }
+    public string? HttpMethod { get; set; }
 
-    public string Url { get; set; }
+    public string Url { get; set; } = default!;
 
-    public IList<string> SupportedVersions { get; set; }
+    public IList<string>? SupportedVersions { get; set; }
 
-    public IList<MethodParameterApiDescriptionModel> ParametersOnMethod { get; set; }
+    public IList<MethodParameterApiDescriptionModel> ParametersOnMethod { get; set; } = default!;
 
-    public IList<ParameterApiDescriptionModel> Parameters { get; set; }
+    public IList<ParameterApiDescriptionModel> Parameters { get; set; } = default!;
 
-    public ReturnValueApiDescriptionModel ReturnValue { get; set; }
+    public ReturnValueApiDescriptionModel ReturnValue { get; set; } = default!;
 
     public bool? AllowAnonymous { get; set; }
 
-    public string ImplementFrom { get; set; }
+    public string? ImplementFrom { get; set; }
 
     public ActionApiDescriptionModel()
     {
 
     }
 
-    public static ActionApiDescriptionModel Create([NotNull] string uniqueName, [NotNull] MethodInfo method, [NotNull] string url, [CanBeNull] string httpMethod, [NotNull] IList<string> supportedVersions, bool? allowAnonymous = null, string implementFrom = null)
+    public static ActionApiDescriptionModel Create([NotNull] string uniqueName, [NotNull] MethodInfo method, [NotNull] string url, string? httpMethod, [NotNull] IList<string> supportedVersions, bool? allowAnonymous = null, string? implementFrom = null)
     {
         Check.NotNull(uniqueName, nameof(uniqueName));
         Check.NotNull(method, nameof(method));
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApiTypeNameHelper.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApiTypeNameHelper.cs
index 6907287f88..a9062655d0 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApiTypeNameHelper.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApiTypeNameHelper.cs
@@ -17,16 +17,16 @@ public static class ApiTypeNameHelper
 
         if (TypeHelper.IsDictionary(type, out var keyType, out var valueType))
         {
-            if (!duplicateTypes.Contains(keyType) && !duplicateTypes.Contains(valueType))
+            if (!duplicateTypes.Contains(keyType!) && !duplicateTypes.Contains(valueType!))
             {
-                return $"{{{GetTypeName(keyType, duplicateTypes)}:{GetTypeName(valueType, duplicateTypes)}}}";
+                return $"{{{GetTypeName(keyType!, duplicateTypes)}:{GetTypeName(valueType!, duplicateTypes)}}}";
             }
         }
         else if (TypeHelper.IsEnumerable(type, out var itemType, includePrimitives: false))
         {
-            if (!duplicateTypes.Contains(itemType))
+            if (!duplicateTypes.Contains(itemType!))
             {
-                return $"[{GetTypeName(itemType, duplicateTypes)}]";
+                return $"[{GetTypeName(itemType!, duplicateTypes)}]";
             }
         }
 
@@ -44,16 +44,16 @@ public static class ApiTypeNameHelper
 
         if (TypeHelper.IsDictionary(type, out var keyType, out var valueType))
         {
-            if (!duplicateTypes.Contains(keyType) && !duplicateTypes.Contains(valueType))
+            if (!duplicateTypes.Contains(keyType!) && !duplicateTypes.Contains(valueType!))
             {
-                return $"{{{GetSimpleTypeName(keyType, duplicateTypes)}:{GetSimpleTypeName(valueType, duplicateTypes)}}}";
+                return $"{{{GetSimpleTypeName(keyType!, duplicateTypes)}:{GetSimpleTypeName(valueType!, duplicateTypes)}}}";
             }
         }
         else if (TypeHelper.IsEnumerable(type, out var itemType, includePrimitives: false))
         {
-            if (!duplicateTypes.Contains(itemType))
+            if (!duplicateTypes.Contains(itemType!))
             {
-                return $"[{GetSimpleTypeName(itemType, duplicateTypes)}]";
+                return $"[{GetSimpleTypeName(itemType!, duplicateTypes)}]";
             }
         }
 
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApplicationApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApplicationApiDescriptionModel.cs
index edebd656cb..03b3751125 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApplicationApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ApplicationApiDescriptionModel.cs
@@ -8,9 +8,9 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class ApplicationApiDescriptionModel
 {
-    public IDictionary<string, ModuleApiDescriptionModel> Modules { get; set; }
+    public IDictionary<string, ModuleApiDescriptionModel> Modules { get; set; } = default!;
 
-    public IDictionary<string, TypeApiDescriptionModel> Types { get; set; }
+    public IDictionary<string, TypeApiDescriptionModel> Types { get; set; } = default!;
 
     public ApplicationApiDescriptionModel()
     {
@@ -41,7 +41,7 @@ public class ApplicationApiDescriptionModel
         return Modules.GetOrAdd(rootPath, () => ModuleApiDescriptionModel.Create(rootPath, remoteServiceName));
     }
 
-    public ApplicationApiDescriptionModel CreateSubModel(string[] modules = null, string[] controllers = null, string[] actions = null)
+    public ApplicationApiDescriptionModel CreateSubModel(string[]? modules = null, string[]? controllers = null, string[]? actions = null)
     {
         var subModel = ApplicationApiDescriptionModel.Create(); ;
 
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerApiDescriptionModel.cs
index e2e0e53e9f..97919e54ba 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerApiDescriptionModel.cs
@@ -8,28 +8,28 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class ControllerApiDescriptionModel
 {
-    public string ControllerName { get; set; }
+    public string ControllerName { get; set; } = default!;
 
-    public string ControllerGroupName { get; set; }
+    public string? ControllerGroupName { get; set; }
 
     public bool IsRemoteService { get; set; }
 
     public bool IsIntegrationService { get; set; }
 
-    public string ApiVersion { get; set; }
+    public string? ApiVersion { get; set; }
 
-    public string Type { get; set; }
+    public string Type { get; set; } = default!;
 
-    public List<ControllerInterfaceApiDescriptionModel> Interfaces { get; set; }
+    public List<ControllerInterfaceApiDescriptionModel> Interfaces { get; set; } = default!;
 
-    public Dictionary<string, ActionApiDescriptionModel> Actions { get; set; }
+    public Dictionary<string, ActionApiDescriptionModel> Actions { get; set; } = default!;
 
     public ControllerApiDescriptionModel()
     {
 
     }
 
-    public static ControllerApiDescriptionModel Create(string controllerName, string groupName, bool isRemoteService, bool isIntegrationService, string apiVersion, Type type, [CanBeNull] HashSet<Type> ignoredInterfaces = null)
+    public static ControllerApiDescriptionModel Create(string controllerName, string? groupName, bool isRemoteService, bool isIntegrationService, string? apiVersion, Type type, HashSet<Type>? ignoredInterfaces = null)
     {
         return new ControllerApiDescriptionModel
         {
@@ -38,11 +38,11 @@ public class ControllerApiDescriptionModel
             IsRemoteService = isRemoteService,
             IsIntegrationService = isIntegrationService, //IntegrationServiceAttribute.IsDefinedOrInherited(type),
             ApiVersion = apiVersion,
-            Type = type.FullName,
+            Type = type.FullName!,
             Actions = new Dictionary<string, ActionApiDescriptionModel>(),
             Interfaces = type
                 .GetInterfaces()
-                .WhereIf(ignoredInterfaces != null, i => !i.IsGenericType && !ignoredInterfaces.Contains(i))
+                .WhereIf(ignoredInterfaces != null, i => !i.IsGenericType && !ignoredInterfaces!.Contains(i))
                 .Select(ControllerInterfaceApiDescriptionModel.Create)
                 .ToList()
         };
@@ -60,7 +60,7 @@ public class ControllerApiDescriptionModel
         return Actions[uniqueName] = action;
     }
 
-    public ControllerApiDescriptionModel CreateSubModel(string[] actions)
+    public ControllerApiDescriptionModel CreateSubModel(string[]? actions)
     {
         var subModel = new ControllerApiDescriptionModel
         {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerInterfaceApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerInterfaceApiDescriptionModel.cs
index a0cfe31e26..a95e2ac547 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerInterfaceApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ControllerInterfaceApiDescriptionModel.cs
@@ -8,11 +8,11 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class ControllerInterfaceApiDescriptionModel
 {
-    public string Type { get; set; }
+    public string Type { get; set; } = default!;
 
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public InterfaceMethodApiDescriptionModel[] Methods { get; set; }
+    public InterfaceMethodApiDescriptionModel[] Methods { get; set; } = default!;
 
     public ControllerInterfaceApiDescriptionModel()
     {
@@ -23,7 +23,7 @@ public class ControllerInterfaceApiDescriptionModel
     {
         var model = new ControllerInterfaceApiDescriptionModel
         {
-            Type = type.FullName,
+            Type = type.FullName!,
             Name = type.Name
         };
 
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/InterfaceMethodApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/InterfaceMethodApiDescriptionModel.cs
index 53a4349854..32b79ce3e1 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/InterfaceMethodApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/InterfaceMethodApiDescriptionModel.cs
@@ -9,11 +9,11 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class InterfaceMethodApiDescriptionModel
 {
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public IList<MethodParameterApiDescriptionModel> ParametersOnMethod { get; set; }
+    public IList<MethodParameterApiDescriptionModel> ParametersOnMethod { get; set; } = default!;
 
-    public ReturnValueApiDescriptionModel ReturnValue { get; set; }
+    public ReturnValueApiDescriptionModel ReturnValue { get; set; } = default!;
 
     public InterfaceMethodApiDescriptionModel()
     {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/MethodParameterApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/MethodParameterApiDescriptionModel.cs
index ed1de76c0e..c3ff20b897 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/MethodParameterApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/MethodParameterApiDescriptionModel.cs
@@ -7,17 +7,17 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class MethodParameterApiDescriptionModel
 {
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public string TypeAsString { get; set; }
+    public string TypeAsString { get; set; } = default!;
 
-    public string Type { get; set; }
+    public string Type { get; set; } = default!;
 
-    public string TypeSimple { get; set; }
+    public string TypeSimple { get; set; } = default!;
 
     public bool IsOptional { get; set; }
 
-    public object DefaultValue { get; set; }
+    public object? DefaultValue { get; set; }
 
     public MethodParameterApiDescriptionModel()
     {
@@ -28,7 +28,7 @@ public class MethodParameterApiDescriptionModel
     {
         return new MethodParameterApiDescriptionModel
         {
-            Name = parameterInfo.Name,
+            Name = parameterInfo.Name!,
             TypeAsString = parameterInfo.ParameterType.GetFullNameWithAssemblyName(),
             Type = TypeHelper.GetFullNameHandlingNullableAndGenerics(parameterInfo.ParameterType),
             TypeSimple = ApiTypeNameHelper.GetSimpleTypeName(parameterInfo.ParameterType),
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ModuleApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ModuleApiDescriptionModel.cs
index bb2c25e3eb..3a7607376c 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ModuleApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ModuleApiDescriptionModel.cs
@@ -18,11 +18,11 @@ public class ModuleApiDescriptionModel
     /// </summary>
     public const string DefaultRemoteServiceName = "Default";
 
-    public string RootPath { get; set; }
+    public string RootPath { get; set; } = default!;
 
-    public string RemoteServiceName { get; set; }
+    public string RemoteServiceName { get; set; } = default!;
 
-    public IDictionary<string, ControllerApiDescriptionModel> Controllers { get; set; }
+    public IDictionary<string, ControllerApiDescriptionModel> Controllers { get; set; } = default!;
 
     public ModuleApiDescriptionModel()
     {
@@ -49,13 +49,13 @@ public class ModuleApiDescriptionModel
         return Controllers[controller.Type] = controller;
     }
 
-    public ControllerApiDescriptionModel GetOrAddController(string name, string groupName, bool isRemoteService, bool isIntegrationService, string apiVersion, Type type, [CanBeNull] HashSet<Type> ignoredInterfaces = null)
+    public ControllerApiDescriptionModel GetOrAddController(string name, string? groupName, bool isRemoteService, bool isIntegrationService, string? apiVersion, Type type, HashSet<Type>? ignoredInterfaces = null)
     {
-        var key = apiVersion.IsNullOrWhiteSpace() ? type.FullName : $"{apiVersion + "."}{type.FullName}";
+        var key = (apiVersion.IsNullOrWhiteSpace() ? type.FullName : $"{apiVersion + "."}{type.FullName}")!;
         return Controllers.GetOrAdd(key, () => ControllerApiDescriptionModel.Create(name, groupName, isRemoteService, isIntegrationService, apiVersion, type, ignoredInterfaces));
     }
 
-    public ModuleApiDescriptionModel CreateSubModel(string[] controllers, string[] actions)
+    public ModuleApiDescriptionModel CreateSubModel(string[]? controllers, string[]? actions)
     {
         var subModel = Create(RootPath, RemoteServiceName);
 
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ParameterApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ParameterApiDescriptionModel.cs
index cf080a857e..a863d1bfad 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ParameterApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ParameterApiDescriptionModel.cs
@@ -6,32 +6,32 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class ParameterApiDescriptionModel
 {
-    public string NameOnMethod { get; set; }
+    public string NameOnMethod { get; set; } = default!;
 
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public string JsonName { get; set; }
+    public string? JsonName { get; set; }
 
-    public string Type { get; set; }
+    public string? Type { get; set; }
 
-    public string TypeSimple { get; set; }
+    public string? TypeSimple { get; set; }
 
     public bool IsOptional { get; set; }
 
-    public object DefaultValue { get; set; }
+    public object? DefaultValue { get; set; }
 
-    public string[] ConstraintTypes { get; set; }
+    public string[]? ConstraintTypes { get; set; }
 
-    public string BindingSourceId { get; set; }
+    public string? BindingSourceId { get; set; }
 
-    public string DescriptorName { get; set; }
+    public string? DescriptorName { get; set; }
 
     public ParameterApiDescriptionModel()
     {
 
     }
 
-    public static ParameterApiDescriptionModel Create(string name, string jsonName, string nameOnMethod, Type type, bool isOptional = false, object defaultValue = null, string[] constraintTypes = null, string bindingSourceId = null, string descriptorName = null)
+    public static ParameterApiDescriptionModel Create(string name, string? jsonName, string nameOnMethod, Type type, bool isOptional = false, object? defaultValue = null, string[]? constraintTypes = null, string? bindingSourceId = null, string? descriptorName = null)
     {
         return new ParameterApiDescriptionModel
         {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/PropertyApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/PropertyApiDescriptionModel.cs
index bd3852098b..03aca1fc29 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/PropertyApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/PropertyApiDescriptionModel.cs
@@ -9,13 +9,13 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class PropertyApiDescriptionModel
 {
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public string JsonName { get; set; }
+    public string? JsonName { get; set; }
 
-    public string Type { get; set; }
+    public string Type { get; set; } = default!;
 
-    public string TypeSimple { get; set; }
+    public string TypeSimple { get; set; } = default!;
 
     public bool IsRequired { get; set; }
 
@@ -23,11 +23,11 @@ public class PropertyApiDescriptionModel
 
     public int? MaxLength { get; set; }
 
-    public string Minimum { get; set; }
+    public string? Minimum { get; set; }
 
-    public string Maximum { get; set; }
+    public string? Maximum { get; set; }
 
-    public string Regex { get; set; }
+    public string? Regex { get; set; }
 
     public static PropertyApiDescriptionModel Create(PropertyInfo propertyInfo)
     {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ReturnValueApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ReturnValueApiDescriptionModel.cs
index 675eab3c82..e5a7e120a8 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ReturnValueApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/ReturnValueApiDescriptionModel.cs
@@ -7,9 +7,9 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class ReturnValueApiDescriptionModel
 {
-    public string Type { get; set; }
+    public string Type { get; set; } = default!;
 
-    public string TypeSimple { get; set; }
+    public string TypeSimple { get; set; } = default!;
 
     public ReturnValueApiDescriptionModel()
     {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/TypeApiDescriptionModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/TypeApiDescriptionModel.cs
index 6a9faa71d7..eaeb02f002 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/TypeApiDescriptionModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/Modeling/TypeApiDescriptionModel.cs
@@ -7,17 +7,17 @@ namespace Volo.Abp.Http.Modeling;
 [Serializable]
 public class TypeApiDescriptionModel
 {
-    public string BaseType { get; set; }
+    public string? BaseType { get; set; }
 
     public bool IsEnum { get; set; }
 
-    public string[] EnumNames { get; set; }
+    public string[]? EnumNames { get; set; }
 
-    public object[] EnumValues { get; set; }
+    public object[]? EnumValues { get; set; }
 
-    public string[] GenericArguments { get; set; }
+    public string[]? GenericArguments { get; set; }
 
-    public PropertyApiDescriptionModel[] Properties { get; set; }
+    public PropertyApiDescriptionModel[]? Properties { get; set; }
 
     public TypeApiDescriptionModel()
     {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Configuration/AbpApiProxyScriptingConfiguration.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Configuration/AbpApiProxyScriptingConfiguration.cs
index 86449c8971..eb8ee307b5 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Configuration/AbpApiProxyScriptingConfiguration.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Configuration/AbpApiProxyScriptingConfiguration.cs
@@ -5,7 +5,7 @@ namespace Volo.Abp.Http.ProxyScripting.Configuration;
 
 public static class AbpApiProxyScriptingConfiguration
 {
-    public static Func<PropertyInfo, string> PropertyNameGenerator { get; set; }
+    public static Func<PropertyInfo, string?> PropertyNameGenerator { get; set; }
 
     static AbpApiProxyScriptingConfiguration()
     {
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/JQuery/JQueryProxyScriptGenerator.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/JQuery/JQueryProxyScriptGenerator.cs
index f7383f0465..b5973eed8a 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/JQuery/JQueryProxyScriptGenerator.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/JQuery/JQueryProxyScriptGenerator.cs
@@ -135,16 +135,16 @@ public class JQueryProxyScriptGenerator : IProxyScriptGenerator, ITransientDepen
     private static string FindBestApiVersion(ActionApiDescriptionModel action)
     {
         //var configuredVersion = GetConfiguredApiVersion(); //TODO: Implement
-        string configuredVersion = null;
+        string? configuredVersion = null;
 
         if (action.SupportedVersions.IsNullOrEmpty())
         {
             return configuredVersion ?? "1.0";
         }
 
-        if (action.SupportedVersions.Contains(configuredVersion))
+        if (action.SupportedVersions!.Contains(configuredVersion!))
         {
-            return configuredVersion;
+            return configuredVersion!;
         }
 
         return action.SupportedVersions.Last(); //TODO: Ensure to get the latest version!
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/ProxyScriptingHelper.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/ProxyScriptingHelper.cs
index 4b43eb70c7..40cc5c4719 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/ProxyScriptingHelper.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/Generators/ProxyScriptingHelper.cs
@@ -25,7 +25,7 @@ internal static class ProxyScriptingHelper
         }
     }
 
-    public static string GenerateHeaders(ActionApiDescriptionModel action, int indent = 0)
+    public static string? GenerateHeaders(ActionApiDescriptionModel action, int indent = 0)
     {
         var parameters = action
             .Parameters
@@ -40,7 +40,7 @@ internal static class ProxyScriptingHelper
         return ProxyScriptingJsFuncHelper.CreateJsObjectLiteral(parameters, indent);
     }
 
-    public static string GenerateBody(ActionApiDescriptionModel action)
+    public static string? GenerateBody(ActionApiDescriptionModel action)
     {
         var parameters = action
             .Parameters
@@ -62,7 +62,7 @@ internal static class ProxyScriptingHelper
         return ProxyScriptingJsFuncHelper.GetParamNameInJsFunc(parameters[0]);
     }
 
-    public static string GenerateFormPostData(ActionApiDescriptionModel action, int indent = 0)
+    public static string? GenerateFormPostData(ActionApiDescriptionModel action, int indent = 0)
     {
         var parameters = action
             .Parameters
diff --git a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/ProxyScriptingModel.cs b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/ProxyScriptingModel.cs
index b165977076..e3eecb0f60 100644
--- a/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/ProxyScriptingModel.cs
+++ b/framework/src/Volo.Abp.Http/Volo/Abp/Http/ProxyScripting/ProxyScriptingModel.cs
@@ -8,11 +8,11 @@ public class ProxyScriptingModel
 
     public bool UseCache { get; set; }
 
-    public string[] Modules { get; set; }
+    public string[]? Modules { get; set; }
 
-    public string[] Controllers { get; set; }
+    public string[]? Controllers { get; set; }
 
-    public string[] Actions { get; set; }
+    public string[]? Actions { get; set; }
 
     public IDictionary<string, string> Properties { get; set; }
 
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo.Abp.IdentityModel.csproj b/framework/src/Volo.Abp.IdentityModel/Volo.Abp.IdentityModel.csproj
index a707f58b9c..b0c2b3e567 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo.Abp.IdentityModel.csproj
+++ b/framework/src/Volo.Abp.IdentityModel/Volo.Abp.IdentityModel.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.IdentityModel</AssemblyName>
     <PackageId>Volo.Abp.IdentityModel</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/AbpIdentityClientOptions.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/AbpIdentityClientOptions.cs
index 364d2dc2ea..62fc21a5fa 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/AbpIdentityClientOptions.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/AbpIdentityClientOptions.cs
@@ -14,7 +14,7 @@ public class AbpIdentityClientOptions
         IdentityClients = new IdentityClientConfigurationDictionary();
     }
 
-    public IdentityClientConfiguration GetClientConfiguration(ICurrentTenant currentTenant, string identityClientName = null)
+    public IdentityClientConfiguration? GetClientConfiguration(ICurrentTenant currentTenant, string? identityClientName = null)
     {
         if (identityClientName.IsNullOrWhiteSpace())
         {
@@ -35,7 +35,7 @@ public class AbpIdentityClientOptions
             }
         }
 
-        return IdentityClients.GetOrDefault(identityClientName) ??
+        return IdentityClients.GetOrDefault(identityClientName!) ??
                IdentityClients.Default;
     }
 }
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IIdentityModelAuthenticationService.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IIdentityModelAuthenticationService.cs
index fee1a032fb..8a5902bdbf 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IIdentityModelAuthenticationService.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IIdentityModelAuthenticationService.cs
@@ -9,7 +9,7 @@ public interface IIdentityModelAuthenticationService
 {
     Task<bool> TryAuthenticateAsync(
         [NotNull] HttpClient client,
-        string identityClientName = null);
+        string? identityClientName = null);
 
     Task<string> GetAccessTokenAsync(
         IdentityClientConfiguration configuration);
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfiguration.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfiguration.cs
index 8faf3225ab..011e40b4b3 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfiguration.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfiguration.cs
@@ -5,14 +5,14 @@ using IdentityModel;
 
 namespace Volo.Abp.IdentityModel;
 
-public class IdentityClientConfiguration : Dictionary<string, string>
+public class IdentityClientConfiguration : Dictionary<string, string?>
 {
     /// <summary>
     /// Possible values: "client_credentials" or "password".
     /// Default value: "client_credentials".
     /// </summary>
     public string GrantType {
-        get => this.GetOrDefault(nameof(GrantType));
+        get => this.GetOrDefault(nameof(GrantType))!;
         set => this[nameof(GrantType)] = value;
     }
 
@@ -20,7 +20,7 @@ public class IdentityClientConfiguration : Dictionary<string, string>
     /// Client Id.
     /// </summary>
     public string ClientId {
-        get => this.GetOrDefault(nameof(ClientId));
+        get => this.GetOrDefault(nameof(ClientId))!;
         set => this[nameof(ClientId)] = value;
     }
 
@@ -28,7 +28,7 @@ public class IdentityClientConfiguration : Dictionary<string, string>
     /// Client secret (as plain text - without hashed).
     /// </summary>
     public string ClientSecret {
-        get => this.GetOrDefault(nameof(ClientSecret));
+        get => this.GetOrDefault(nameof(ClientSecret))!;
         set => this[nameof(ClientSecret)] = value;
     }
 
@@ -36,7 +36,7 @@ public class IdentityClientConfiguration : Dictionary<string, string>
     /// User name.
     /// Valid only if <see cref="GrantType"/> is "password".
     /// </summary>
-    public string UserName {
+    public string? UserName {
         get => this.GetOrDefault(nameof(UserName));
         set => this[nameof(UserName)] = value;
     }
@@ -45,7 +45,7 @@ public class IdentityClientConfiguration : Dictionary<string, string>
     /// Password of the <see cref="UserName"/>.
     /// Valid only if <see cref="GrantType"/> is "password".
     /// </summary>
-    public string UserPassword {
+    public string? UserPassword {
         get => this.GetOrDefault(nameof(UserPassword));
         set => this[nameof(UserPassword)] = value;
     }
@@ -54,7 +54,7 @@ public class IdentityClientConfiguration : Dictionary<string, string>
     /// Authority.
     /// </summary>
     public string Authority {
-        get => this.GetOrDefault(nameof(Authority));
+        get => this.GetOrDefault(nameof(Authority))!;
         set => this[nameof(Authority)] = value;
     }
 
@@ -62,7 +62,7 @@ public class IdentityClientConfiguration : Dictionary<string, string>
     /// Scope.
     /// </summary>
     public string Scope {
-        get => this.GetOrDefault(nameof(Scope));
+        get => this.GetOrDefault(nameof(Scope))!;
         set => this[nameof(Scope)] = value;
     }
 
@@ -113,8 +113,8 @@ public class IdentityClientConfiguration : Dictionary<string, string>
         string clientId,
         string clientSecret,
         string grantType = OidcConstants.GrantTypes.ClientCredentials,
-        string userName = null,
-        string userPassword = null,
+        string? userName = null,
+        string? userPassword = null,
         bool requireHttps = true,
         int cacheAbsoluteExpiration = 60 * 30,
         bool validateIssuerName = true,
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfigurationDictionary.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfigurationDictionary.cs
index e8c42fe390..4993cfa462 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfigurationDictionary.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityClientConfigurationDictionary.cs
@@ -2,11 +2,11 @@
 
 namespace Volo.Abp.IdentityModel;
 
-public class IdentityClientConfigurationDictionary : Dictionary<string, IdentityClientConfiguration>
+public class IdentityClientConfigurationDictionary : Dictionary<string, IdentityClientConfiguration?>
 {
     public const string DefaultName = "Default";
 
-    public IdentityClientConfiguration Default {
+    public IdentityClientConfiguration? Default {
         get => this.GetOrDefault(DefaultName);
         set => this[DefaultName] = value;
     }
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelAuthenticationService.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelAuthenticationService.cs
index 6f5f8eda95..4354d83735 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelAuthenticationService.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelAuthenticationService.cs
@@ -54,7 +54,7 @@ public class IdentityModelAuthenticationService : IIdentityModelAuthenticationSe
 
     public async Task<bool> TryAuthenticateAsync(
         [NotNull] HttpClient client,
-        string identityClientName = null)
+        string? identityClientName = null)
     {
         var accessToken = await GetAccessTokenOrNullAsync(identityClientName);
         if (accessToken == null)
@@ -66,7 +66,7 @@ public class IdentityModelAuthenticationService : IIdentityModelAuthenticationSe
         return true;
     }
 
-    protected virtual async Task<string> GetAccessTokenOrNullAsync(string identityClientName)
+    protected virtual async Task<string?> GetAccessTokenOrNullAsync(string? identityClientName)
     {
         var configuration = ClientOptions.GetClientConfiguration(CurrentTenant, identityClientName);
         if (configuration == null)
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelDiscoveryDocumentCacheItem.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelDiscoveryDocumentCacheItem.cs
index 0fbf50d020..6cabe5d9b9 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelDiscoveryDocumentCacheItem.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelDiscoveryDocumentCacheItem.cs
@@ -7,9 +7,9 @@ namespace Volo.Abp.IdentityModel;
 [IgnoreMultiTenancy]
 public class IdentityModelDiscoveryDocumentCacheItem
 {
-    public string TokenEndpoint { get; set; }
+    public string TokenEndpoint { get; set; } = default!;
 
-    public string DeviceAuthorizationEndpoint { get; set; }
+    public string DeviceAuthorizationEndpoint { get; set; } = default!;
 
     public IdentityModelDiscoveryDocumentCacheItem()
     {
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelHttpRequestMessageOptions.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelHttpRequestMessageOptions.cs
index d72cc9682e..78b2a342f4 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelHttpRequestMessageOptions.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelHttpRequestMessageOptions.cs
@@ -5,5 +5,5 @@ namespace Volo.Abp.IdentityModel;
 
 public class IdentityModelHttpRequestMessageOptions
 {
-    public Action<HttpRequestMessage> ConfigureHttpRequestMessage { get; set; }
+    public Action<HttpRequestMessage>? ConfigureHttpRequestMessage { get; set; }
 }
diff --git a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelTokenCacheItem.cs b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelTokenCacheItem.cs
index 2a164a23e6..72beed1577 100644
--- a/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelTokenCacheItem.cs
+++ b/framework/src/Volo.Abp.IdentityModel/Volo/Abp/IdentityModel/IdentityModelTokenCacheItem.cs
@@ -7,7 +7,7 @@ namespace Volo.Abp.IdentityModel;
 [Serializable]
 public class IdentityModelTokenCacheItem
 {
-    public string AccessToken { get; set; }
+    public string AccessToken { get; set; } = default!;
 
     public IdentityModelTokenCacheItem()
     {