diff --git a/code-generator/pom.xml b/code-generator/pom.xml
index f317bb0..ad623f1 100644
--- a/code-generator/pom.xml
+++ b/code-generator/pom.xml
@@ -46,11 +46,6 @@
             <artifactId>guava</artifactId>
         </dependency>
 
-        <dependency>
-            <groupId>org.jibx</groupId>
-            <artifactId>jibx-tools</artifactId>
-        </dependency>
-
         <dependency>
             <groupId>org.jboss.forge.roaster</groupId>
             <artifactId>roaster-api</artifactId>
@@ -60,6 +55,12 @@
             <artifactId>roaster-jdt</artifactId>
             <scope>runtime</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
diff --git a/code-generator/src/main/java/io/streamnative/lightproto/generator/Util.java b/code-generator/src/main/java/io/streamnative/lightproto/generator/Util.java
index d5151ce..1c407cf 100644
--- a/code-generator/src/main/java/io/streamnative/lightproto/generator/Util.java
+++ b/code-generator/src/main/java/io/streamnative/lightproto/generator/Util.java
@@ -17,9 +17,6 @@
 
 import java.io.PrintWriter;
 
-import org.jibx.schema.codegen.extend.DefaultNameConverter;
-import org.jibx.schema.codegen.extend.NameConverter;
-
 import static com.google.common.base.CaseFormat.LOWER_CAMEL;
 import static com.google.common.base.CaseFormat.LOWER_UNDERSCORE;
 
@@ -66,14 +63,37 @@ public static String upperCase(String... parts) {
         return sb.toString().toUpperCase();
     }
 
-    private static final NameConverter nameTools = new DefaultNameConverter();
-
-    public static String plural(String s) {
-        return nameTools.pluralize(s);
+    // pluralize/singular rules vendored from JiBX NameUtilities
+    // (Copyright (c) 2008-2010, Dennis M. Sosnoski, BSD 3-clause license).
+    public static String plural(String name) {
+        if (name.endsWith("List") || (name.endsWith("s") && !name.endsWith("ss"))) {
+            return name;
+        }
+        if (name.endsWith("y") && !name.endsWith("ay") && !name.endsWith("ey") && !name.endsWith("iy")
+                && !name.endsWith("oy") && !name.endsWith("uy")) {
+            if (name.equalsIgnoreCase("any")) {
+                return name;
+            }
+            return name.substring(0, name.length() - 1) + "ies";
+        } else if (name.endsWith("ss")) {
+            return name + "es";
+        } else {
+            return name + 's';
+        }
     }
 
-    public static String singular(String s) {
-        return nameTools.depluralize(s);
+    public static String singular(String name) {
+        if (name.endsWith("ies")) {
+            return name.substring(0, name.length() - 3) + 'y';
+        } else if (name.endsWith("sses")) {
+            return name.substring(0, name.length() - 2);
+        } else if (name.endsWith("s") && !name.endsWith("ss")) {
+            return name.substring(0, name.length() - 1);
+        } else if (name.endsWith("List")) {
+            return name.substring(0, name.length() - 4);
+        } else {
+            return name;
+        }
     }
 
     public static void writeJavadoc(PrintWriter w, String doc, String indent) {
diff --git a/code-generator/src/test/java/io/streamnative/lightproto/generator/UtilTest.java b/code-generator/src/test/java/io/streamnative/lightproto/generator/UtilTest.java
new file mode 100644
index 0000000..f63fbaa
--- /dev/null
+++ b/code-generator/src/test/java/io/streamnative/lightproto/generator/UtilTest.java
@@ -0,0 +1,92 @@
+/**
+ * Copyright 2026 StreamNative
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.streamnative.lightproto.generator;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+/**
+ * Locks the pluralize/singular behavior inherited from JiBX NameUtilities.
+ * These functions feed into generated public API names (e.g. {@code addItem},
+ * {@code getItemsCount}), so changing their output is an ABI break.
+ */
+class UtilTest {
+
+    @ParameterizedTest
+    @CsvSource({
+            // default case: append 's'
+            "item, items",
+            "book, books",
+            "Message, Messages",
+            // ends with 'ss': append 'es'
+            "address, addresses",
+            "class, classes",
+            // ends with consonant+'y': replace with 'ies'
+            "city, cities",
+            "category, categories",
+            "company, companies",
+            // ends with vowel+'y': default rule, append 's'
+            "day, days",
+            "key, keys",
+            "boy, boys",
+            "guy, guys",
+            "way, ways",
+            // 'any' is a hardcoded exception (case-insensitive match), but
+            // only reached when endsWith("y") matches, which is case-sensitive.
+            // So "ANY" slips through to the default rule.
+            "any, any",
+            "Any, Any",
+            "ANY, ANYs",
+            // already plural ('s' but not 'ss'): unchanged
+            "items, items",
+            "books, books",
+            // ends with 'List': treated as already plural
+            "itemList, itemList",
+            "userList, userList",
+    })
+    void pluralizes(String input, String expected) {
+        assertEquals(expected, Util.plural(input));
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+            // ends with 'ies': replace with 'y'
+            "cities, city",
+            "categories, category",
+            "companies, company",
+            // ends with 'sses': strip 'es'
+            "addresses, address",
+            "classes, class",
+            // ends with 's' (not 'ss'): strip 's'
+            "items, item",
+            "books, book",
+            "days, day",
+            // ends with 'List': strip suffix
+            "itemList, item",
+            "userList, user",
+            // ends with 'ss': unchanged (not a plural)
+            "address, address",
+            "class, class",
+            // no recognized plural marker: unchanged
+            "item, item",
+            "any, any",
+    })
+    void singularizes(String input, String expected) {
+        assertEquals(expected, Util.singular(input));
+    }
+}
diff --git a/pom.xml b/pom.xml
index bee3e9f..ce61a10 100644
--- a/pom.xml
+++ b/pom.xml
@@ -68,7 +68,6 @@
         <junit.version>5.7.0</junit.version>
         <guava.version>32.0.0-jre</guava.version>
         <netty.version>4.1.131.Final</netty.version>
-        <jibx.version>1.3.3</jibx.version>
         <roaster.version>2.22.2.Final</roaster.version>
         <grpc.version>1.68.0</grpc.version>
 
@@ -177,12 +176,6 @@
                 <version>${protobuf.version}</version>
             </dependency>
 
-            <dependency>
-                <groupId>org.jibx</groupId>
-                <artifactId>jibx-tools</artifactId>
-                <version>${jibx.version}</version>
-            </dependency>
-
             <dependency>
                 <groupId>org.openjdk.jmh</groupId>
                 <artifactId>jmh-core</artifactId>