diff --git a/framework/src/Volo.Abp.Kafka/Volo.Abp.Kafka.csproj b/framework/src/Volo.Abp.Kafka/Volo.Abp.Kafka.csproj
index f66761fc2a..e56bd38916 100644
--- a/framework/src/Volo.Abp.Kafka/Volo.Abp.Kafka.csproj
+++ b/framework/src/Volo.Abp.Kafka/Volo.Abp.Kafka.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <RootNamespace />
     </PropertyGroup>
 
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/AbpKafkaOptions.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/AbpKafkaOptions.cs
index b48a952615..11b443f72b 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/AbpKafkaOptions.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/AbpKafkaOptions.cs
@@ -8,11 +8,11 @@ public class AbpKafkaOptions
 {
     public KafkaConnections Connections { get; }
 
-    public Action<ProducerConfig> ConfigureProducer { get; set; }
+    public Action<ProducerConfig>? ConfigureProducer { get; set; }
 
-    public Action<ConsumerConfig> ConfigureConsumer { get; set; }
+    public Action<ConsumerConfig>? ConfigureConsumer { get; set; }
 
-    public Action<TopicSpecification> ConfigureTopic { get; set; }
+    public Action<TopicSpecification>? ConfigureTopic { get; set; }
 
     public AbpKafkaOptions()
     {
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ConsumerPool.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ConsumerPool.cs
index 7c73df0d51..48943c84c4 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ConsumerPool.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ConsumerPool.cs
@@ -30,7 +30,7 @@ public class ConsumerPool : IConsumerPool, ISingletonDependency
         Logger = new NullLogger<ConsumerPool>();
     }
 
-    public virtual IConsumer<string, byte[]> Get(string groupId, string connectionName = null)
+    public virtual IConsumer<string, byte[]> Get(string groupId, string? connectionName = null)
     {
         connectionName ??= KafkaConnections.DefaultConnectionName;
 
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IConsumerPool.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IConsumerPool.cs
index 4666a0175f..a3f484ef56 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IConsumerPool.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IConsumerPool.cs
@@ -5,5 +5,5 @@ namespace Volo.Abp.Kafka;
 
 public interface IConsumerPool : IDisposable
 {
-    IConsumer<string, byte[]> Get(string groupId, string connectionName = null);
+    IConsumer<string, byte[]> Get(string groupId, string? connectionName = null);
 }
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IKafkaMessageConsumerFactory.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IKafkaMessageConsumerFactory.cs
index e21c8c9fd2..985e20625f 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IKafkaMessageConsumerFactory.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IKafkaMessageConsumerFactory.cs
@@ -14,5 +14,5 @@ public interface IKafkaMessageConsumerFactory
     IKafkaMessageConsumer Create(
         string topicName,
         string groupId,
-        string connectionName = null);
+        string? connectionName = null);
 }
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IProducerPool.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IProducerPool.cs
index 8930184016..378075b2ec 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IProducerPool.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/IProducerPool.cs
@@ -5,5 +5,5 @@ namespace Volo.Abp.Kafka;
 
 public interface IProducerPool : IDisposable
 {
-    IProducer<string, byte[]> Get(string connectionName = null);
+    IProducer<string, byte[]> Get(string? connectionName = null);
 }
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaConnections.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaConnections.cs
index 3d9f2fe950..e66e074ad6 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaConnections.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaConnections.cs
@@ -21,8 +21,10 @@ public class KafkaConnections : Dictionary<string, ClientConfig>
         Default = new ClientConfig();
     }
 
-    public ClientConfig GetOrDefault(string connectionName)
+    public ClientConfig GetOrDefault(string? connectionName)
     {
+        connectionName ??= DefaultConnectionName;
+        
         if (TryGetValue(connectionName, out var connectionFactory))
         {
             return connectionFactory;
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumer.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumer.cs
index 704c15845f..5a2ba38189 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumer.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumer.cs
@@ -31,13 +31,13 @@ public class KafkaMessageConsumer : IKafkaMessageConsumer, ITransientDependency,
 
     protected ConcurrentBag<Func<Message<string, byte[]>, Task>> Callbacks { get; }
 
-    protected IConsumer<string, byte[]> Consumer { get; private set; }
+    protected IConsumer<string, byte[]>? Consumer { get; private set; }
 
-    protected string ConnectionName { get; private set; }
+    protected string? ConnectionName { get; private set; }
 
-    protected string GroupId { get; private set; }
+    protected string GroupId { get; private set; } = default!;
 
-    protected string TopicName { get; private set; }
+    protected string TopicName { get; private set; } = default!;
 
     public KafkaMessageConsumer(
         IConsumerPool consumerPool,
@@ -63,7 +63,7 @@ public class KafkaMessageConsumer : IKafkaMessageConsumer, ITransientDependency,
     public virtual void Initialize(
         [NotNull] string topicName,
         [NotNull] string groupId,
-        string connectionName = null)
+        string? connectionName = null)
     {
         Check.NotNull(topicName, nameof(topicName));
         Check.NotNull(groupId, nameof(groupId));
@@ -160,7 +160,7 @@ public class KafkaMessageConsumer : IKafkaMessageConsumer, ITransientDependency,
         }
         finally
         {
-            Consumer.Commit(consumeResult);
+            Consumer?.Commit(consumeResult);
         }
     }
 
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumerFactory.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumerFactory.cs
index dfc5912d55..fe46b5fe38 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumerFactory.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/KafkaMessageConsumerFactory.cs
@@ -16,7 +16,7 @@ public class KafkaMessageConsumerFactory : IKafkaMessageConsumerFactory, ISingle
     public IKafkaMessageConsumer Create(
         string topicName,
         string groupId,
-        string connectionName = null)
+        string? connectionName = null)
     {
         var consumer = ServiceScope.ServiceProvider.GetRequiredService<KafkaMessageConsumer>();
         consumer.Initialize(topicName, groupId, connectionName);
diff --git a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ProducerPool.cs b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ProducerPool.cs
index ac2edf31a7..23b9b71a57 100644
--- a/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ProducerPool.cs
+++ b/framework/src/Volo.Abp.Kafka/Volo/Abp/Kafka/ProducerPool.cs
@@ -32,7 +32,7 @@ public class ProducerPool : IProducerPool, ISingletonDependency
         Logger = new NullLogger<ProducerPool>();
     }
 
-    public virtual IProducer<string, byte[]> Get(string connectionName = null)
+    public virtual IProducer<string, byte[]> Get(string? connectionName = null)
     {
         connectionName ??= KafkaConnections.DefaultConnectionName;