diff --git a/src/Unosquare.Labs.EmbedIO.BearerToken/BearerToken.cs b/src/Unosquare.Labs.EmbedIO.BearerToken/BearerToken.cs
index e53cee6..ebd5beb 100644
--- a/src/Unosquare.Labs.EmbedIO.BearerToken/BearerToken.cs
+++ b/src/Unosquare.Labs.EmbedIO.BearerToken/BearerToken.cs
@@ -29,6 +29,6 @@ public class BearerToken
         /// Client username.
         /// </summary>
         [JsonProperty("userName")]
-        public string Username { get; set; }
+        public string? Username { get; set; }
     }
 }
diff --git a/src/Unosquare.Labs.EmbedIO.BearerToken/BearerTokenModule.cs b/src/Unosquare.Labs.EmbedIO.BearerToken/BearerTokenModule.cs
index 41f8f98..ddd72cb 100644
--- a/src/Unosquare.Labs.EmbedIO.BearerToken/BearerTokenModule.cs
+++ b/src/Unosquare.Labs.EmbedIO.BearerToken/BearerTokenModule.cs
@@ -1,6 +1,9 @@
-namespace EmbedIO.BearerToken
+using Swan.Formatters;
+
+namespace EmbedIO.BearerToken
 {
     using Microsoft.IdentityModel.Tokens;
+    using System.Collections.Generic;
     using System;
     using System.Text;
     using System.Threading.Tasks;
@@ -67,6 +70,14 @@ public BearerTokenModule(
         /// </value>
         public SymmetricSecurityKey SecretKey { get; }
 
+        /// <summary>
+        /// Gets or sets the on success transformation method.
+        /// </summary>
+        /// <value>
+        /// The on success.
+        /// </value>
+        public Action<IDictionary<string, object>>? OnSuccessTransformation { get; set; }
+
         /// <inheritdoc />
         public override bool IsFinalHandler => false;
 
@@ -107,14 +118,20 @@ await _authorizationServerProvider.ValidateClientAuthentication(validationContex
                 DateTime.FromBinary(_authorizationServerProvider.GetExpirationDate()),
                 DateTimeKind.Utc);
 
+            var token = new BearerToken
+            {
+                Token = validationContext.GetToken(SecretKey, expiryDate),
+                TokenType = "bearer",
+                ExpirationDate = _authorizationServerProvider.GetExpirationDate(),
+                Username = validationContext.IdentityName,
+            };
+
+            var dictToken = Json.Deserialize<Dictionary<string, object>>(Json.Serialize(token));
+
+            OnSuccessTransformation?.Invoke(dictToken);
+
             await context
-                .SendDataAsync(new BearerToken
-                {
-                    Token = validationContext.GetToken(SecretKey, expiryDate),
-                    TokenType = "bearer",
-                    ExpirationDate = _authorizationServerProvider.GetExpirationDate(),
-                    Username = validationContext.IdentityName,
-                })
+                .SendDataAsync(dictToken)
                 .ConfigureAwait(false);
         }
     }
diff --git a/src/Unosquare.Labs.EmbedIO.BearerToken/Unosquare.Labs.EmbedIO.BearerToken.csproj b/src/Unosquare.Labs.EmbedIO.BearerToken/Unosquare.Labs.EmbedIO.BearerToken.csproj
index 55a4b67..5a2d587 100644
--- a/src/Unosquare.Labs.EmbedIO.BearerToken/Unosquare.Labs.EmbedIO.BearerToken.csproj
+++ b/src/Unosquare.Labs.EmbedIO.BearerToken/Unosquare.Labs.EmbedIO.BearerToken.csproj
@@ -10,7 +10,7 @@
     <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
     <CodeAnalysisRuleSet>..\..\StyleCop.Analyzers.ruleset</CodeAnalysisRuleSet>
-    <Version>3.2.0</Version>
+    <Version>3.3.0</Version>
     <RootNamespace>EmbedIO.BearerToken</RootNamespace>
   </PropertyGroup>
 
diff --git a/src/Unosquare.Labs.EmbedIO.ExtraSample/Program.cs b/src/Unosquare.Labs.EmbedIO.ExtraSample/Program.cs
index a827f5c..95c286e 100644
--- a/src/Unosquare.Labs.EmbedIO.ExtraSample/Program.cs
+++ b/src/Unosquare.Labs.EmbedIO.ExtraSample/Program.cs
@@ -45,9 +45,17 @@ private static async Task Main(string[] args)
                 tokenSource.Cancel();
             }, tokenSource.Token);
 
+            var bearerTokenModule = new BearerTokenModule(
+                "/api",
+                authServer,
+                "0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9eyJjbGF")
+            {
+                OnSuccessTransformation = dict => { dict.Add("logged", true); },
+            };
+
             // Our web server is disposable. 
             using var server = new WebServer(url)
-                .WithBearerToken("/api", "0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9eyJjbGF", authServer)
+                .WithModule(bearerTokenModule)
                 .WithModule(new JsonServerModule(jsonPath: Path.Combine(WebRootPath, "database.json")))
                 .WithModule(new MarkdownStaticModule("/", WebRootPath));
 
diff --git a/src/Unosquare.Labs.EmbedIO.ExtraSample/Unosquare.Labs.EmbedIO.ExtraSample.csproj b/src/Unosquare.Labs.EmbedIO.ExtraSample/Unosquare.Labs.EmbedIO.ExtraSample.csproj
index ee6a63f..02e06dd 100644
--- a/src/Unosquare.Labs.EmbedIO.ExtraSample/Unosquare.Labs.EmbedIO.ExtraSample.csproj
+++ b/src/Unosquare.Labs.EmbedIO.ExtraSample/Unosquare.Labs.EmbedIO.ExtraSample.csproj
@@ -7,6 +7,7 @@
     <OutputType>Exe</OutputType>
     <CodeAnalysisRuleSet>..\..\StyleCop.Analyzers.ruleset</CodeAnalysisRuleSet>
     <LangVersion>8.0</LangVersion>
+    <Nullable>enable</Nullable>
     <RootNamespace>EmbedIO.ExtraSample</RootNamespace>
   </PropertyGroup>