diff --git a/VAR.ExpressionEvaluator/ITokenizer.cs b/VAR.ExpressionEvaluator/ITokenizer.cs
new file mode 100644
index 0000000..ac5a737
--- /dev/null
+++ b/VAR.ExpressionEvaluator/ITokenizer.cs
@@ -0,0 +1,13 @@
+namespace VAR.ExpressionEvaluator
+{
+    public interface ITokenizer
+    {
+        Token Token { get; }
+
+        string Text { get; }
+
+        decimal? Number { get; }
+
+        void NextToken();
+    }
+}
\ No newline at end of file
diff --git a/VAR.ExpressionEvaluator/Token.cs b/VAR.ExpressionEvaluator/Token.cs
new file mode 100644
index 0000000..abc5f1b
--- /dev/null
+++ b/VAR.ExpressionEvaluator/Token.cs
@@ -0,0 +1,23 @@
+namespace VAR.ExpressionEvaluator
+{
+    public enum Token
+    {
+        EOF,
+        Plus,
+        Minus,
+        Division,
+        Multiply,
+        Equals,
+        ExclusiveEquals,
+        GreaterThan,
+        GreaterOrEqualThan,
+        LessThan,
+        LessOrEqualThan,
+        ParentesisStart,
+        ParentesisEnd,
+        Keyword,
+        String,
+        Number,
+    }
+
+}
diff --git a/VAR.ExpressionEvaluator/Tokenizer.cs b/VAR.ExpressionEvaluator/Tokenizer.cs
index 7122724..57f9e8b 100644
--- a/VAR.ExpressionEvaluator/Tokenizer.cs
+++ b/VAR.ExpressionEvaluator/Tokenizer.cs
@@ -4,27 +4,7 @@ using System.Text;
 
 namespace VAR.ExpressionEvaluator
 {
-    public enum Token
-    {
-        EOF,
-        Plus,
-        Minus,
-        Division,
-        Multiply,
-        Equals,
-        ExclusiveEquals,
-        GreaterThan,
-        GreaterOrEqualThan,
-        LessThan,
-        LessOrEqualThan,
-        ParentesisStart,
-        ParentesisEnd,
-        Keyword,
-        String,
-        Number,
-    }
-
-    public class Tokenizer
+    public class Tokenizer : ITokenizer
     {
         private TextReader _reader;
         private int _currentPosition = 0;
diff --git a/VAR.ExpressionEvaluator/VAR.ExpressionEvaluator.csproj b/VAR.ExpressionEvaluator/VAR.ExpressionEvaluator.csproj
index 49d1738..6495ec0 100644
--- a/VAR.ExpressionEvaluator/VAR.ExpressionEvaluator.csproj
+++ b/VAR.ExpressionEvaluator/VAR.ExpressionEvaluator.csproj
@@ -45,7 +45,9 @@
     <Compile Include="ExpressionStringNode.cs" />
     <Compile Include="ExpressionNumberNode.cs" />
     <Compile Include="IExpressionNode.cs" />
+    <Compile Include="ITokenizer.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Token.cs" />
     <Compile Include="Tokenizer.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />