diff --git a/src/SampleApp/Sample/ProcessHandler.cs b/src/SampleApp/Sample/ProcessHandler.cs
new file mode 100644
index 0000000..43cac76
--- /dev/null
+++ b/src/SampleApp/Sample/ProcessHandler.cs
@@ -0,0 +1,59 @@
+using System.Runtime.CompilerServices;
+using System.Text.Json;
+using Devlooped.WhatsApp;
+using Microsoft.Extensions.Logging;
+
+class ProcessHandler(ILogger<Program> logger, JsonSerializerOptions options) : IWhatsAppHandler
+{
+    public async IAsyncEnumerable<Response> HandleAsync(IEnumerable<IMessage> messages, [EnumeratorCancellation] CancellationToken cancellation = default)
+    {
+        // Avoid warning CS1998 // Async method lacks 'await' operators and will run synchronously
+        await Task.CompletedTask;
+
+        var message = messages.Last();
+        logger.LogInformation("💬 Received message: {Message}", message);
+
+        if (message is ErrorMessage error)
+        {
+            // Reengagement error, we need to invite the user.
+            if (error.Error.Code == 131047)
+            {
+                // Showcases how to use a pre-declared template response to reengage the user.
+                yield return error.Template("reengagement", "es_AR");
+            }
+            else
+            {
+                logger.LogWarning("⚠️ Unknown error message received: {Error}", message);
+            }
+        }
+        else if (message is InteractiveMessage interactive)
+        {
+            logger.LogWarning("👤 chose {Button} ({Title})", interactive.Button.Id, interactive.Button.Title);
+            yield return interactive.Reply($"👤 chose: {interactive.Button.Title} ({interactive.Button.Id})");
+        }
+        else if (message is ReactionMessage reaction)
+        {
+            logger.LogInformation("👤 reaction: {Reaction}", reaction.Emoji);
+            yield return reaction.Reply($"👤 reaction: {reaction.Emoji}");
+        }
+        else if (message is StatusMessage status)
+        {
+            logger.LogInformation("☑️ status: {Status}", status.Status);
+        }
+        else if (message is ContentMessage content)
+        {
+            yield return content.React("🧠");
+
+            // simulate some hard work at hand, like doing some LLM-stuff :)
+            //await Task.Delay(2000);
+            yield return content.Reply(
+                $"☑️ Got your {content.Content.Type}:\r\n{JsonSerializer.Serialize(content, options)}",
+                new Button("btn_good", "👍"),
+                new Button("btn_bad", "👎"));
+        }
+        else if (message is UnsupportedMessage unsupported)
+        {
+            logger.LogWarning("⚠️ {Message}", unsupported);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/SampleApp/Sample/Program.cs b/src/SampleApp/Sample/Program.cs
index 13289fb..fbc19d9 100644
--- a/src/SampleApp/Sample/Program.cs
+++ b/src/SampleApp/Sample/Program.cs
@@ -1,5 +1,4 @@
-using System.Runtime.CompilerServices;
-using System.Text.Json;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 using Devlooped;
 using Devlooped.WhatsApp;
@@ -42,67 +41,11 @@
     throw new InvalidOperationException("Missing required App:Storage connection string."));
 
 builder.Services
-    .AddWhatsApp<ILogger<Program>, JsonSerializerOptions>(builder.Configuration, ProcessMessagesAsync)
+    .AddWhatsApp<ProcessHandler>(builder.Configuration)
     // Matches what we use in ConfigureOpenTelemetry
     .UseOpenTelemetry(builder.Environment.ApplicationName)
     .UseLogging()
     .UseStorage()
     .UseConversation();
 
-builder.Build().Run();
-
-static async IAsyncEnumerable<Response> ProcessMessagesAsync(
-    ILogger<Program> logger,
-    JsonSerializerOptions options,
-    IEnumerable<IMessage> messages,
-    [EnumeratorCancellation] CancellationToken cancellationToken)
-{
-    // Avoid warning CS1998 // Async method lacks 'await' operators and will run synchronously
-    await Task.CompletedTask;
-
-    var message = messages.Last();
-    logger.LogInformation("💬 Received message: {Message}", message);
-
-    if (message is ErrorMessage error)
-    {
-        // Reengagement error, we need to invite the user.
-        if (error.Error.Code == 131047)
-        {
-            // Showcases how to use a pre-declared template response to reengage the user.
-            yield return error.Template("reengagement", "es_AR");
-        }
-        else
-        {
-            logger.LogWarning("⚠️ Unknown error message received: {Error}", message);
-        }
-    }
-    else if (message is InteractiveMessage interactive)
-    {
-        logger.LogWarning("👤 chose {Button} ({Title})", interactive.Button.Id, interactive.Button.Title);
-        yield return interactive.Reply($"👤 chose: {interactive.Button.Title} ({interactive.Button.Id})");
-    }
-    else if (message is ReactionMessage reaction)
-    {
-        logger.LogInformation("👤 reaction: {Reaction}", reaction.Emoji);
-        yield return reaction.Reply($"👤 reaction: {reaction.Emoji}");
-    }
-    else if (message is StatusMessage status)
-    {
-        logger.LogInformation("☑️ status: {Status}", status.Status);
-    }
-    else if (message is ContentMessage content)
-    {
-        yield return content.React("🧠");
-
-        // simulate some hard work at hand, like doing some LLM-stuff :)
-        //await Task.Delay(2000);
-        yield return content.Reply(
-            $"☑️ Got your {content.Content.Type}:\r\n{JsonSerializer.Serialize(content, options)}",
-            new Button("btn_good", "👍"),
-            new Button("btn_bad", "👎"));
-    }
-    else if (message is UnsupportedMessage unsupported)
-    {
-        logger.LogWarning("⚠️ {Message}", unsupported);
-    }
-}
+builder.Build().Run();
\ No newline at end of file
diff --git a/src/WhatsApp/WhatsAppServiceCollectionExtensions.cs b/src/WhatsApp/WhatsAppServiceCollectionExtensions.cs
index d254bd6..244ff70 100644
--- a/src/WhatsApp/WhatsAppServiceCollectionExtensions.cs
+++ b/src/WhatsApp/WhatsAppServiceCollectionExtensions.cs
@@ -126,9 +126,12 @@ public static WhatsAppHandlerBuilder AddWhatsApp<THandler>(
         ServiceLifetime lifetime = ServiceLifetime.Singleton)
         where THandler : class, IWhatsAppHandler
     {
-        collection.Add(new ServiceDescriptor(typeof(IWhatsAppHandler), services => services.GetRequiredService<THandler>(), lifetime));
+        if (collection.FirstOrDefault(x => x.ServiceType == typeof(THandler)) == null)
+        {
+            collection.Add(new ServiceDescriptor(typeof(THandler), typeof(THandler), lifetime));
+        }
 
-        return collection.AddWhatsApp(configuration, services => services.GetRequiredService<IWhatsAppHandler>(), lifetime);
+        return collection.AddWhatsApp(configuration, services => services.GetRequiredService<THandler>(), lifetime);
     }
 
     /// <summary>