diff --git a/PCAxis.Sql.UnitTest/ApiUtilStaticTests.cs b/PCAxis.Sql.UnitTest/ApiUtilStaticTests.cs
new file mode 100644
index 0000000..e82a517
--- /dev/null
+++ b/PCAxis.Sql.UnitTest/ApiUtilStaticTests.cs
@@ -0,0 +1,66 @@
+using System;
+using System.Reflection;
+using System.Runtime.ExceptionServices;
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+using PCAxis.Sql.ApiUtils;
+
+namespace PCAxis.Sql.UnitTest
+{
+
+    [TestClass]
+    public class ApiUtilStaticTests
+    {
+
+        [TestMethod]
+        [TestCategory("Unit")]
+        //[DataRow("valid_id_string")]
+        //[DataRow("1.1")]
+        //[DataRow("v123")]
+        //[DataRow("123")]
+        //[DataRow("COICOP MI1301 (fin)")]
+        //[DataRow("COFOG2+3-siffer")]
+        [DataRow("F_AntalBarn<6Bakgr")]
+        [DataRow("F_AntalBarn>6Bakgr")]
+        public void ValidateIdString_GivenValidValues_ReturnsSameValue(string value)
+        {
+            string result = InvokeValidateIdString(value);
+            Assert.AreEqual(value, result);
+        }
+
+        [TestMethod]
+        [TestCategory("Unit")]
+        public void ValidateIdString_GivenNull_ThrowsArgumentException()
+        {
+            // Act + Assert
+            Assert.ThrowsExactly<ArgumentException>(() => InvokeValidateIdString(null));
+        }
+
+        [TestMethod]
+        [TestCategory("Unit")]
+        public void ValidateIdString_GivenInvalidCharacters_ThrowsArgumentException()
+        {
+            // Arrange
+            var invalidId = "table/id";
+
+            Assert.ThrowsExactly<ArgumentException>(() => InvokeValidateIdString(invalidId));
+        }
+
+        private static string InvokeValidateIdString(string input)
+        {
+            var method = typeof(ApiUtilStatic).GetMethod("ValidateIdString", BindingFlags.NonPublic | BindingFlags.Static);
+            Assert.IsNotNull(method);
+
+            try
+            {
+                return (string)method.Invoke(null, new object[] { input });
+            }
+            catch (TargetInvocationException ex) when (ex.InnerException != null)
+            {
+                ExceptionDispatchInfo.Capture(ex.InnerException).Throw();
+                throw;
+            }
+        }
+    }
+}
diff --git a/PCAxis.Sql.UnitTest/PCAxis.Sql.UnitTest.csproj b/PCAxis.Sql.UnitTest/PCAxis.Sql.UnitTest.csproj
index 3aef7ae..c9d3da5 100644
--- a/PCAxis.Sql.UnitTest/PCAxis.Sql.UnitTest.csproj
+++ b/PCAxis.Sql.UnitTest/PCAxis.Sql.UnitTest.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
diff --git a/PCAxis.Sql/ApiUtils/ApiUtilStatic.cs b/PCAxis.Sql/ApiUtils/ApiUtilStatic.cs
index f523788..0847d4c 100644
--- a/PCAxis.Sql/ApiUtils/ApiUtilStatic.cs
+++ b/PCAxis.Sql/ApiUtils/ApiUtilStatic.cs
@@ -19,13 +19,7 @@ namespace PCAxis.Sql.ApiUtils
     public static class ApiUtilStatic
     {
 
-        private static readonly List<string> LanguagesInDbConfig;
-        static ApiUtilStatic()
-        {
-            Console.WriteLine("Start ApiUtilStatic");
-            var config = SqlDbConfigsStatic.DefaultDatabase;
-            LanguagesInDbConfig = config.ListAllLanguages();
-        }
+        private static readonly Lazy<List<string>> LanguagesInDbConfig = new Lazy<List<string>>(() => SqlDbConfigsStatic.DefaultDatabase.ListAllLanguages());
 
         //Exceptions ?  What if the valueset only exists in another language: Exceptions!
         static public ValueSet GetValueSet(string valueSetId, string language)
@@ -118,7 +112,7 @@ private static string ValidateLangCodeString(string input)
             {
                 throw new ArgumentException("The language cannot be null.");
             }
-            if (!LanguagesInDbConfig.Contains(input))
+            if (!LanguagesInDbConfig.Value.Contains(input))
             {
                 throw new ArgumentException("Cant find language in config.");
             }
@@ -133,9 +127,9 @@ private static string ValidateIdString(string input)
                 throw new ArgumentException("The id string cannot be null.");
             }
 
-            if (!Regex.IsMatch(input, @"^[\w\t \-:.]+$", RegexOptions.None, TimeSpan.FromSeconds(2)))
+            if (!Regex.IsMatch(input, @"^[\w\t \-:.\(\)\+<>]+$", RegexOptions.None, TimeSpan.FromSeconds(2)))
             {
-                throw new ArgumentException("The string contains invalid characters. Only letters, digits, underscores, tabs, spaces, hyphens, colons and periods are allowed.");
+                throw new ArgumentException("The string contains invalid characters. Only letters, digits, underscores, tabs, spaces, hyphens, colons, periods, parentheses, plus and angle brackets are allowed.");
             }
             return input;
         }