diff --git a/vertx-codegen-protobuf/src/converters/generated/dataobjects.proto b/vertx-codegen-protobuf/src/converters/generated/dataobjects.proto
index b210ad988..a5fc0eb34 100644
--- a/vertx-codegen-protobuf/src/converters/generated/dataobjects.proto
+++ b/vertx-codegen-protobuf/src/converters/generated/dataobjects.proto
@@ -43,6 +43,13 @@ message RecursiveItem {
   RecursiveItem childC = 4;
 }
 
+message SimplePojo {
+  int32 integerField = 1;
+  int64 longField = 2;
+  bool booleanField = 3;
+  string stringField = 4;
+}
+
 message User {
   string userName = 1;
   int32 age = 2;
diff --git a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/AddressProtoConverter.java b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/AddressProtoConverter.java
index 863756ed3..3e210a732 100644
--- a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/AddressProtoConverter.java
+++ b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/AddressProtoConverter.java
@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Arrays;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
 import io.vertx.core.json.JsonObject;
 import io.vertx.codegen.protobuf.utils.ExpandableIntArray;
 import io.vertx.codegen.protobuf.converters.*;
@@ -17,6 +18,16 @@
 public class AddressProtoConverter {
 
   public static void fromProto(CodedInputStream input, Address obj) throws IOException {
+    fromProto(input, obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void fromProto(CodedInputStream input, Address obj, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    if (compatibleMode) {
+      obj.setName("");
+      obj.setLongitude(0f);
+      obj.setLatitude(0f);
+    }
     int tag;
     while ((tag = input.readTag()) != 0) {
       switch (tag) {
@@ -33,36 +44,57 @@ public static void fromProto(CodedInputStream input, Address obj) throws IOExcep
           break;
         }
       }
-    }
+    } // while loop
   }
 
   public static void toProto(Address obj, CodedOutputStream output) throws IOException {
+    toProto(obj, output, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void toProto(Address obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    AddressProtoConverter.computeSize(obj, cache, 0);
-    AddressProtoConverter.toProto(obj, output, cache, 0);
+    AddressProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    AddressProtoConverter.toProto(obj, output, cache, 0, encodingMode);
   }
 
-  public static int toProto(Address obj, CodedOutputStream output, ExpandableIntArray cache, int index) throws IOException {
+  static int toProto(Address obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
     index = index + 1;
-    if (obj.getName() != null) {
+    // name
+    if (compatibleMode && obj.getName() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getName() != null) || (compatibleMode && !obj.getName().isEmpty())) {
       output.writeString(1, obj.getName());
     }
-    if (obj.getLongitude() != null) {
+    // longitude
+    if (compatibleMode && obj.getLongitude() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getLongitude() != null) || (compatibleMode && obj.getLongitude() != 0f)) {
       output.writeFloat(2, obj.getLongitude());
     }
-    if (obj.getLatitude() != null) {
+    // latitude
+    if (compatibleMode && obj.getLatitude() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getLatitude() != null) || (compatibleMode && obj.getLatitude() != 0f)) {
       output.writeFloat(3, obj.getLatitude());
     }
     return index;
   }
 
   public static int computeSize(Address obj) {
+    return computeSize(obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static int computeSize(Address obj, ProtobufEncodingMode encodingMode) {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    AddressProtoConverter.computeSize(obj, cache, 0);
+    AddressProtoConverter.computeSize(obj, cache, 0, encodingMode);
     return cache.get(0);
   }
 
-  public static int computeSize(Address obj, ExpandableIntArray cache, final int baseIndex) {
+  static int computeSize(Address obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {
     int size = 0;
     int index = baseIndex + 1;
     if (obj.getName() != null) {
diff --git a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/BookProtoConverter.java b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/BookProtoConverter.java
index 0b617d0c9..cdfefae5f 100644
--- a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/BookProtoConverter.java
+++ b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/BookProtoConverter.java
@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Arrays;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
 import io.vertx.core.json.JsonObject;
 import io.vertx.codegen.protobuf.utils.ExpandableIntArray;
 import io.vertx.codegen.protobuf.converters.*;
@@ -17,6 +18,17 @@
 public class BookProtoConverter {
 
   public static void fromProto(CodedInputStream input, Book obj) throws IOException {
+    fromProto(input, obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void fromProto(CodedInputStream input, Book obj, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    if (compatibleMode) {
+      obj.setName("");
+      obj.setAuthor("");
+      obj.setIsbn("");
+      obj.setGenre("");
+    }
     int tag;
     while ((tag = input.readTag()) != 0) {
       switch (tag) {
@@ -37,39 +49,64 @@ public static void fromProto(CodedInputStream input, Book obj) throws IOExceptio
           break;
         }
       }
-    }
+    } // while loop
   }
 
   public static void toProto(Book obj, CodedOutputStream output) throws IOException {
+    toProto(obj, output, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void toProto(Book obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    BookProtoConverter.computeSize(obj, cache, 0);
-    BookProtoConverter.toProto(obj, output, cache, 0);
+    BookProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    BookProtoConverter.toProto(obj, output, cache, 0, encodingMode);
   }
 
-  public static int toProto(Book obj, CodedOutputStream output, ExpandableIntArray cache, int index) throws IOException {
+  static int toProto(Book obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
     index = index + 1;
-    if (obj.getName() != null) {
+    // name
+    if (compatibleMode && obj.getName() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getName() != null) || (compatibleMode && !obj.getName().isEmpty())) {
       output.writeString(1, obj.getName());
     }
-    if (obj.getAuthor() != null) {
+    // author
+    if (compatibleMode && obj.getAuthor() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getAuthor() != null) || (compatibleMode && !obj.getAuthor().isEmpty())) {
       output.writeString(3, obj.getAuthor());
     }
-    if (obj.getIsbn() != null) {
+    // isbn
+    if (compatibleMode && obj.getIsbn() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getIsbn() != null) || (compatibleMode && !obj.getIsbn().isEmpty())) {
       output.writeString(10, obj.getIsbn());
     }
-    if (obj.getGenre() != null) {
+    // genre
+    if (compatibleMode && obj.getGenre() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getGenre() != null) || (compatibleMode && !obj.getGenre().isEmpty())) {
       output.writeString(20, obj.getGenre());
     }
     return index;
   }
 
   public static int computeSize(Book obj) {
+    return computeSize(obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static int computeSize(Book obj, ProtobufEncodingMode encodingMode) {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    BookProtoConverter.computeSize(obj, cache, 0);
+    BookProtoConverter.computeSize(obj, cache, 0, encodingMode);
     return cache.get(0);
   }
 
-  public static int computeSize(Book obj, ExpandableIntArray cache, final int baseIndex) {
+  static int computeSize(Book obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {
     int size = 0;
     int index = baseIndex + 1;
     if (obj.getName() != null) {
diff --git a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/PersonProtoConverter.java b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/PersonProtoConverter.java
index 46002f198..6b752d547 100644
--- a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/PersonProtoConverter.java
+++ b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/PersonProtoConverter.java
@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Arrays;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
 import io.vertx.core.json.JsonObject;
 import io.vertx.codegen.protobuf.utils.ExpandableIntArray;
 import io.vertx.codegen.protobuf.converters.*;
@@ -17,6 +18,14 @@
 public class PersonProtoConverter {
 
   public static void fromProto(CodedInputStream input, Person obj) throws IOException {
+    fromProto(input, obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void fromProto(CodedInputStream input, Person obj, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    if (compatibleMode) {
+      obj.setName("");
+    }
     int tag;
     while ((tag = input.readTag()) != 0) {
       switch (tag) {
@@ -29,20 +38,30 @@ public static void fromProto(CodedInputStream input, Person obj) throws IOExcept
           break;
         }
       }
-    }
+    } // while loop
   }
 
   public static void toProto(Person obj, CodedOutputStream output) throws IOException {
+    toProto(obj, output, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void toProto(Person obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    PersonProtoConverter.computeSize(obj, cache, 0);
-    PersonProtoConverter.toProto(obj, output, cache, 0);
+    PersonProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    PersonProtoConverter.toProto(obj, output, cache, 0, encodingMode);
   }
 
-  public static int toProto(Person obj, CodedOutputStream output, ExpandableIntArray cache, int index) throws IOException {
+  static int toProto(Person obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
     index = index + 1;
-    if (obj.getName() != null) {
+    // name
+    if (compatibleMode && obj.getName() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getName() != null) || (compatibleMode && !obj.getName().isEmpty())) {
       output.writeString(2, obj.getName());
     }
+    // age
     if (obj.getAge() != 0) {
       output.writeInt32(4, obj.getAge());
     }
@@ -50,12 +69,16 @@ public static int toProto(Person obj, CodedOutputStream output, ExpandableIntArr
   }
 
   public static int computeSize(Person obj) {
+    return computeSize(obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static int computeSize(Person obj, ProtobufEncodingMode encodingMode) {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    PersonProtoConverter.computeSize(obj, cache, 0);
+    PersonProtoConverter.computeSize(obj, cache, 0, encodingMode);
     return cache.get(0);
   }
 
-  public static int computeSize(Person obj, ExpandableIntArray cache, final int baseIndex) {
+  static int computeSize(Person obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {
     int size = 0;
     int index = baseIndex + 1;
     if (obj.getName() != null) {
diff --git a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/RecursiveItemProtoConverter.java b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/RecursiveItemProtoConverter.java
index 659e4273d..86be31240 100644
--- a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/RecursiveItemProtoConverter.java
+++ b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/RecursiveItemProtoConverter.java
@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Arrays;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
 import io.vertx.core.json.JsonObject;
 import io.vertx.codegen.protobuf.utils.ExpandableIntArray;
 import io.vertx.codegen.protobuf.converters.*;
@@ -17,6 +18,14 @@
 public class RecursiveItemProtoConverter {
 
   public static void fromProto(CodedInputStream input, RecursiveItem obj) throws IOException {
+    fromProto(input, obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void fromProto(CodedInputStream input, RecursiveItem obj, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    if (compatibleMode) {
+      obj.setId("");
+    }
     int tag;
     while ((tag = input.readTag()) != 0) {
       switch (tag) {
@@ -52,45 +61,61 @@ public static void fromProto(CodedInputStream input, RecursiveItem obj) throws I
           break;
         }
       }
-    }
+    } // while loop
   }
 
   public static void toProto(RecursiveItem obj, CodedOutputStream output) throws IOException {
+    toProto(obj, output, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void toProto(RecursiveItem obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    RecursiveItemProtoConverter.computeSize(obj, cache, 0);
-    RecursiveItemProtoConverter.toProto(obj, output, cache, 0);
+    RecursiveItemProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    RecursiveItemProtoConverter.toProto(obj, output, cache, 0, encodingMode);
   }
 
-  public static int toProto(RecursiveItem obj, CodedOutputStream output, ExpandableIntArray cache, int index) throws IOException {
+  static int toProto(RecursiveItem obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
     index = index + 1;
-    if (obj.getId() != null) {
+    // id
+    if (compatibleMode && obj.getId() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getId() != null) || (compatibleMode && !obj.getId().isEmpty())) {
       output.writeString(1, obj.getId());
     }
+    // childA
     if (obj.getChildA() != null) {
       output.writeUInt32NoTag(18);
       output.writeUInt32NoTag(cache.get(index));
-      index = RecursiveItemProtoConverter.toProto(obj.getChildA(), output, cache, index);
+      index = RecursiveItemProtoConverter.toProto(obj.getChildA(), output, cache, index, encodingMode);
     }
+    // childB
     if (obj.getChildB() != null) {
       output.writeUInt32NoTag(26);
       output.writeUInt32NoTag(cache.get(index));
-      index = RecursiveItemProtoConverter.toProto(obj.getChildB(), output, cache, index);
+      index = RecursiveItemProtoConverter.toProto(obj.getChildB(), output, cache, index, encodingMode);
     }
+    // childC
     if (obj.getChildC() != null) {
       output.writeUInt32NoTag(34);
       output.writeUInt32NoTag(cache.get(index));
-      index = RecursiveItemProtoConverter.toProto(obj.getChildC(), output, cache, index);
+      index = RecursiveItemProtoConverter.toProto(obj.getChildC(), output, cache, index, encodingMode);
     }
     return index;
   }
 
   public static int computeSize(RecursiveItem obj) {
+    return computeSize(obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static int computeSize(RecursiveItem obj, ProtobufEncodingMode encodingMode) {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    RecursiveItemProtoConverter.computeSize(obj, cache, 0);
+    RecursiveItemProtoConverter.computeSize(obj, cache, 0, encodingMode);
     return cache.get(0);
   }
 
-  public static int computeSize(RecursiveItem obj, ExpandableIntArray cache, final int baseIndex) {
+  static int computeSize(RecursiveItem obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {
     int size = 0;
     int index = baseIndex + 1;
     if (obj.getId() != null) {
@@ -99,7 +124,7 @@ public static int computeSize(RecursiveItem obj, ExpandableIntArray cache, final
     if (obj.getChildA() != null) {
       size += CodedOutputStream.computeUInt32SizeNoTag(18);
       int savedIndex = index;
-      index = RecursiveItemProtoConverter.computeSize(obj.getChildA(), cache, index);
+      index = RecursiveItemProtoConverter.computeSize(obj.getChildA(), cache, index, encodingMode);
       int dataSize = cache.get(savedIndex);
       size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);
       size += dataSize;
@@ -107,7 +132,7 @@ public static int computeSize(RecursiveItem obj, ExpandableIntArray cache, final
     if (obj.getChildB() != null) {
       size += CodedOutputStream.computeUInt32SizeNoTag(26);
       int savedIndex = index;
-      index = RecursiveItemProtoConverter.computeSize(obj.getChildB(), cache, index);
+      index = RecursiveItemProtoConverter.computeSize(obj.getChildB(), cache, index, encodingMode);
       int dataSize = cache.get(savedIndex);
       size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);
       size += dataSize;
@@ -115,7 +140,7 @@ public static int computeSize(RecursiveItem obj, ExpandableIntArray cache, final
     if (obj.getChildC() != null) {
       size += CodedOutputStream.computeUInt32SizeNoTag(34);
       int savedIndex = index;
-      index = RecursiveItemProtoConverter.computeSize(obj.getChildC(), cache, index);
+      index = RecursiveItemProtoConverter.computeSize(obj.getChildC(), cache, index, encodingMode);
       int dataSize = cache.get(savedIndex);
       size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);
       size += dataSize;
diff --git a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/SimplePojoProtoConverter.java b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/SimplePojoProtoConverter.java
new file mode 100644
index 000000000..decb01c7a
--- /dev/null
+++ b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/SimplePojoProtoConverter.java
@@ -0,0 +1,128 @@
+package io.vertx.test.codegen.converter;
+
+import com.google.protobuf.CodedOutputStream;
+import com.google.protobuf.CodedInputStream;
+import java.io.IOException;
+import java.time.Instant;
+import java.time.ZonedDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Arrays;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
+import io.vertx.core.json.JsonObject;
+import io.vertx.codegen.protobuf.utils.ExpandableIntArray;
+import io.vertx.codegen.protobuf.converters.*;
+
+public class SimplePojoProtoConverter {
+
+  public static void fromProto(CodedInputStream input, SimplePojo obj) throws IOException {
+    fromProto(input, obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void fromProto(CodedInputStream input, SimplePojo obj, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    if (compatibleMode) {
+      obj.setIntegerField(0);
+      obj.setLongField(0L);
+      obj.setBooleanField(false);
+      obj.setStringField("");
+    }
+    int tag;
+    while ((tag = input.readTag()) != 0) {
+      switch (tag) {
+        case 8: {
+          obj.setIntegerField(input.readInt32());
+          break;
+        }
+        case 16: {
+          obj.setLongField(input.readInt64());
+          break;
+        }
+        case 24: {
+          obj.setBooleanField(input.readBool());
+          break;
+        }
+        case 34: {
+          obj.setStringField(input.readString());
+          break;
+        }
+      }
+    } // while loop
+  }
+
+  public static void toProto(SimplePojo obj, CodedOutputStream output) throws IOException {
+    toProto(obj, output, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void toProto(SimplePojo obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {
+    ExpandableIntArray cache = new ExpandableIntArray(16);
+    SimplePojoProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    SimplePojoProtoConverter.toProto(obj, output, cache, 0, encodingMode);
+  }
+
+  static int toProto(SimplePojo obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    index = index + 1;
+    // integerField
+    if (compatibleMode && obj.getIntegerField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getIntegerField() != null) || (compatibleMode && obj.getIntegerField() != 0)) {
+      output.writeInt32(1, obj.getIntegerField());
+    }
+    // longField
+    if (compatibleMode && obj.getLongField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getLongField() != null) || (compatibleMode && obj.getLongField() != 0L)) {
+      output.writeInt64(2, obj.getLongField());
+    }
+    // booleanField
+    if (compatibleMode && obj.getBooleanField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getBooleanField() != null) || (compatibleMode && !obj.getBooleanField())) {
+      output.writeBool(3, obj.getBooleanField());
+    }
+    // stringField
+    if (compatibleMode && obj.getStringField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getStringField() != null) || (compatibleMode && !obj.getStringField().isEmpty())) {
+      output.writeString(4, obj.getStringField());
+    }
+    return index;
+  }
+
+  public static int computeSize(SimplePojo obj) {
+    return computeSize(obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static int computeSize(SimplePojo obj, ProtobufEncodingMode encodingMode) {
+    ExpandableIntArray cache = new ExpandableIntArray(16);
+    SimplePojoProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    return cache.get(0);
+  }
+
+  static int computeSize(SimplePojo obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {
+    int size = 0;
+    int index = baseIndex + 1;
+    if (obj.getIntegerField() != null) {
+      size += CodedOutputStream.computeInt32Size(1, obj.getIntegerField());
+    }
+    if (obj.getLongField() != null) {
+      size += CodedOutputStream.computeInt64Size(2, obj.getLongField());
+    }
+    if (obj.getBooleanField() != null) {
+      size += CodedOutputStream.computeBoolSize(3, obj.getBooleanField());
+    }
+    if (obj.getStringField() != null) {
+      size += CodedOutputStream.computeStringSize(4, obj.getStringField());
+    }
+    cache.set(baseIndex, size);
+    return index;
+  }
+
+}
diff --git a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/UserProtoConverter.java b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/UserProtoConverter.java
index c1dd876e7..5eae5c42e 100644
--- a/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/UserProtoConverter.java
+++ b/vertx-codegen-protobuf/src/converters/generated/io/vertx/test/codegen/converter/UserProtoConverter.java
@@ -10,6 +10,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Arrays;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
 import io.vertx.core.json.JsonObject;
 import io.vertx.codegen.protobuf.utils.ExpandableIntArray;
 import io.vertx.codegen.protobuf.converters.*;
@@ -17,6 +18,20 @@
 public class UserProtoConverter {
 
   public static void fromProto(CodedInputStream input, User obj) throws IOException {
+    fromProto(input, obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void fromProto(CodedInputStream input, User obj, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
+    if (compatibleMode) {
+      obj.setUserName("");
+      obj.setAge(0);
+      obj.setDoubleField(0d);
+      obj.setFloatField(0f);
+      obj.setLongField(0L);
+      obj.setBoolField(false);
+      obj.setShortField((short)0);
+    }
     int tag;
     while ((tag = input.readTag()) != 0) {
       switch (tag) {
@@ -271,23 +286,37 @@ public static void fromProto(CodedInputStream input, User obj) throws IOExceptio
           break;
         }
       }
-    }
+    } // while loop
   }
 
   public static void toProto(User obj, CodedOutputStream output) throws IOException {
+    toProto(obj, output, ProtobufEncodingMode.VERTX);
+  }
+
+  public static void toProto(User obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    UserProtoConverter.computeSize(obj, cache, 0);
-    UserProtoConverter.toProto(obj, output, cache, 0);
+    UserProtoConverter.computeSize(obj, cache, 0, encodingMode);
+    UserProtoConverter.toProto(obj, output, cache, 0, encodingMode);
   }
 
-  public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray cache, int index) throws IOException {
+  static int toProto(User obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {
+    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;
     index = index + 1;
-    if (obj.getUserName() != null) {
+    // userName
+    if (compatibleMode && obj.getUserName() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getUserName() != null) || (compatibleMode && !obj.getUserName().isEmpty())) {
       output.writeString(1, obj.getUserName());
     }
-    if (obj.getAge() != null) {
+    // age
+    if (compatibleMode && obj.getAge() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getAge() != null) || (compatibleMode && obj.getAge() != 0)) {
       output.writeInt32(2, obj.getAge());
     }
+    // integerListField
     if (obj.getIntegerListField() != null) {
       // list | tag | data size | value[0] | value[1] | value[2] |
       if (obj.getIntegerListField().size() > 0) {
@@ -302,15 +331,17 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         }
       }
     }
+    // structListField
     if (obj.getStructListField() != null) {
       // list[0] | tag | data size | value |
       // list[1] | tag | data size | value |
       for (Address element: obj.getStructListField()) {
         output.writeUInt32NoTag(34);
         output.writeUInt32NoTag(cache.get(index));
-        index = AddressProtoConverter.toProto(element, output, cache, index);
+        index = AddressProtoConverter.toProto(element, output, cache, index, encodingMode);
       }
     }
+    // zonedDateTimeListField
     if (obj.getZonedDateTimeListField() != null) {
       // list[0] | tag | data size | value |
       // list[1] | tag | data size | value |
@@ -320,6 +351,7 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         ZonedDateTimeProtoConverter.toProto(element, output);
       }
     }
+    // jsonListField
     if (obj.getJsonListField() != null) {
       // list[0] | tag | data size | value |
       // list[1] | tag | data size | value |
@@ -329,32 +361,56 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         VertxStructProtoConverter.toProto(element, output);
       }
     }
+    // address
     if (obj.getAddress() != null) {
       output.writeUInt32NoTag(58);
       output.writeUInt32NoTag(cache.get(index));
-      index = AddressProtoConverter.toProto(obj.getAddress(), output, cache, index);
+      index = AddressProtoConverter.toProto(obj.getAddress(), output, cache, index, encodingMode);
     }
+    // byteField
     if (obj.getByteField() != null) {
       output.writeInt32(8, obj.getByteField());
     }
-    if (obj.getDoubleField() != null) {
+    // doubleField
+    if (compatibleMode && obj.getDoubleField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getDoubleField() != null) || (compatibleMode && obj.getDoubleField() != 0d)) {
       output.writeDouble(9, obj.getDoubleField());
     }
-    if (obj.getFloatField() != null) {
+    // floatField
+    if (compatibleMode && obj.getFloatField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getFloatField() != null) || (compatibleMode && obj.getFloatField() != 0f)) {
       output.writeFloat(10, obj.getFloatField());
     }
-    if (obj.getLongField() != null) {
+    // longField
+    if (compatibleMode && obj.getLongField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getLongField() != null) || (compatibleMode && obj.getLongField() != 0L)) {
       output.writeInt64(11, obj.getLongField());
     }
-    if (obj.getBoolField() != null) {
+    // boolField
+    if (compatibleMode && obj.getBoolField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getBoolField() != null) || (compatibleMode && !obj.getBoolField())) {
       output.writeBool(12, obj.getBoolField());
     }
-    if (obj.getShortField() != null) {
+    // shortField
+    if (compatibleMode && obj.getShortField() == null) {
+      throw new IllegalArgumentException("Null values are not allowed for boxed types in compatibility mode");
+    }
+    if ((!compatibleMode && obj.getShortField() != null) || (compatibleMode && obj.getShortField() != (short)0)) {
       output.writeInt32(13, obj.getShortField());
     }
+    // charField
     if (obj.getCharField() != null) {
       output.writeInt32(14, obj.getCharField());
     }
+    // stringValueMap
     if (obj.getStringValueMap() != null) {
       // map[0] | tag | data size | key | value |
       // map[1] | tag | data size | key | value |
@@ -371,6 +427,7 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         output.writeString(2, entry.getValue());
       }
     }
+    // integerValueMap
     if (obj.getIntegerValueMap() != null) {
       // map[0] | tag | data size | key | value |
       // map[1] | tag | data size | key | value |
@@ -387,6 +444,7 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         output.writeInt32(2, entry.getValue());
       }
     }
+    // structValueMap
     if (obj.getStructValueMap() != null) {
       // map[0] | tag | data size | key | value |
       // map[1] | tag | data size | key | value |
@@ -405,9 +463,10 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         output.writeString(1, entry.getKey());
         output.writeUInt32NoTag(18);
         output.writeUInt32NoTag(elementSize);
-        index = AddressProtoConverter.toProto(entry.getValue(), output, cache, index);
+        index = AddressProtoConverter.toProto(entry.getValue(), output, cache, index, encodingMode);
       }
     }
+    // jsonValueMap
     if (obj.getJsonValueMap() != null) {
       // map[0] | tag | data size | key | value |
       // map[1] | tag | data size | key | value |
@@ -429,6 +488,7 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         VertxStructProtoConverter.toProto(entry.getValue(), output);
       }
     }
+    // zonedDateTimeValueMap
     if (obj.getZonedDateTimeValueMap() != null) {
       // map[0] | tag | data size | key | value |
       // map[1] | tag | data size | key | value |
@@ -450,50 +510,63 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
         ZonedDateTimeProtoConverter.toProto(entry.getValue(), output);
       }
     }
+    // zonedDateTimeField
     if (obj.getZonedDateTimeField() != null) {
       output.writeUInt32NoTag(162);
       output.writeUInt32NoTag(ZonedDateTimeProtoConverter.computeSize(obj.getZonedDateTimeField()));
       ZonedDateTimeProtoConverter.toProto(obj.getZonedDateTimeField(), output);
     }
+    // instantField
     if (obj.getInstantField() != null) {
       output.writeUInt32NoTag(170);
       output.writeUInt32NoTag(InstantProtoConverter.computeSize(obj.getInstantField()));
       InstantProtoConverter.toProto(obj.getInstantField(), output);
     }
+    // jsonObjectField
     if (obj.getJsonObjectField() != null) {
       output.writeUInt32NoTag(178);
       output.writeUInt32NoTag(VertxStructProtoConverter.computeSize(obj.getJsonObjectField()));
       VertxStructProtoConverter.toProto(obj.getJsonObjectField(), output);
     }
+    // jsonArrayField
     if (obj.getJsonArrayField() != null) {
       output.writeUInt32NoTag(186);
       output.writeUInt32NoTag(VertxStructListProtoConverter.computeSize(obj.getJsonArrayField()));
       VertxStructListProtoConverter.toProto(obj.getJsonArrayField(), output);
     }
+    // primitiveBoolean
     if (obj.isPrimitiveBoolean()) {
       output.writeBool(24, obj.isPrimitiveBoolean());
     }
+    // primitiveByte
     if (obj.getPrimitiveByte() != 0) {
       output.writeInt32(25, obj.getPrimitiveByte());
     }
+    // primitiveShort
     if (obj.getPrimitiveShort() != 0) {
       output.writeInt32(26, obj.getPrimitiveShort());
     }
+    // primitiveInt
     if (obj.getPrimitiveInt() != 0) {
       output.writeInt32(27, obj.getPrimitiveInt());
     }
+    // primitiveLong
     if (obj.getPrimitiveLong() != 0) {
       output.writeInt64(28, obj.getPrimitiveLong());
     }
+    // primitiveFloat
     if (obj.getPrimitiveFloat() != 0) {
       output.writeFloat(29, obj.getPrimitiveFloat());
     }
+    // primitiveDouble
     if (obj.getPrimitiveDouble() != 0) {
       output.writeDouble(30, obj.getPrimitiveDouble());
     }
+    // primitiveChar
     if (obj.getPrimitiveChar() != 0) {
       output.writeInt32(31, obj.getPrimitiveChar());
     }
+    // enumType
     if (obj.getEnumType() != null) {
       switch (obj.getEnumType()) {
         case A:
@@ -511,12 +584,16 @@ public static int toProto(User obj, CodedOutputStream output, ExpandableIntArray
   }
 
   public static int computeSize(User obj) {
+    return computeSize(obj, ProtobufEncodingMode.VERTX);
+  }
+
+  public static int computeSize(User obj, ProtobufEncodingMode encodingMode) {
     ExpandableIntArray cache = new ExpandableIntArray(16);
-    UserProtoConverter.computeSize(obj, cache, 0);
+    UserProtoConverter.computeSize(obj, cache, 0, encodingMode);
     return cache.get(0);
   }
 
-  public static int computeSize(User obj, ExpandableIntArray cache, final int baseIndex) {
+  static int computeSize(User obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {
     int size = 0;
     int index = baseIndex + 1;
     if (obj.getUserName() != null) {
@@ -544,7 +621,7 @@ public static int computeSize(User obj, ExpandableIntArray cache, final int base
         for (Address element: obj.getStructListField()) {
           size += CodedOutputStream.computeUInt32SizeNoTag(34);
           int savedIndex = index;
-          index = AddressProtoConverter.computeSize(element, cache, index);
+          index = AddressProtoConverter.computeSize(element, cache, index, encodingMode);
           int dataSize = cache.get(savedIndex);
           size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);
           size += dataSize;
@@ -578,7 +655,7 @@ public static int computeSize(User obj, ExpandableIntArray cache, final int base
     if (obj.getAddress() != null) {
       size += CodedOutputStream.computeUInt32SizeNoTag(58);
       int savedIndex = index;
-      index = AddressProtoConverter.computeSize(obj.getAddress(), cache, index);
+      index = AddressProtoConverter.computeSize(obj.getAddress(), cache, index, encodingMode);
       int dataSize = cache.get(savedIndex);
       size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);
       size += dataSize;
@@ -639,7 +716,7 @@ public static int computeSize(User obj, ExpandableIntArray cache, final int base
         dataSize += CodedOutputStream.computeStringSize(1, entry.getKey());
         // value
         int savedIndex = index;
-        index = AddressProtoConverter.computeSize(entry.getValue(), cache, index);
+        index = AddressProtoConverter.computeSize(entry.getValue(), cache, index, encodingMode);
         int elementSize = cache.get(savedIndex);
         dataSize += CodedOutputStream.computeInt32SizeNoTag(18);
         dataSize += CodedOutputStream.computeInt32SizeNoTag(elementSize);
diff --git a/vertx-codegen-protobuf/src/converters/java/io/vertx/test/codegen/converter/SimplePojo.java b/vertx-codegen-protobuf/src/converters/java/io/vertx/test/codegen/converter/SimplePojo.java
new file mode 100644
index 000000000..7ec210e7d
--- /dev/null
+++ b/vertx-codegen-protobuf/src/converters/java/io/vertx/test/codegen/converter/SimplePojo.java
@@ -0,0 +1,61 @@
+package io.vertx.test.codegen.converter;
+
+import io.vertx.codegen.annotations.DataObject;
+import io.vertx.codegen.protobuf.annotations.FieldNumberStrategy;
+import io.vertx.codegen.protobuf.annotations.ProtobufGen;
+
+import java.util.Objects;
+
+@DataObject
+@ProtobufGen(fieldNumberStrategy = FieldNumberStrategy.COMPACT)
+public class SimplePojo {
+  private Integer integerField;
+  private Long LongField;
+  private Boolean booleanField;
+  private String stringField;
+
+  public Integer getIntegerField() {
+    return integerField;
+  }
+
+  public void setIntegerField(Integer integerField) {
+    this.integerField = integerField;
+  }
+
+  public Long getLongField() {
+    return LongField;
+  }
+
+  public void setLongField(Long longField) {
+    LongField = longField;
+  }
+
+  public Boolean getBooleanField() {
+    return booleanField;
+  }
+
+  public void setBooleanField(Boolean booleanField) {
+    this.booleanField = booleanField;
+  }
+
+  public String getStringField() {
+    return stringField;
+  }
+
+  public void setStringField(String stringField) {
+    this.stringField = stringField;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+    SimplePojo that = (SimplePojo) o;
+    return Objects.equals(integerField, that.integerField) && Objects.equals(LongField, that.LongField) && Objects.equals(booleanField, that.booleanField) && Objects.equals(stringField, that.stringField);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(integerField, LongField, booleanField, stringField);
+  }
+}
diff --git a/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/ProtobufEncodingMode.java b/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/ProtobufEncodingMode.java
new file mode 100644
index 000000000..f8de5156d
--- /dev/null
+++ b/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/ProtobufEncodingMode.java
@@ -0,0 +1,19 @@
+package io.vertx.codegen.protobuf;
+
+/**
+ * Enumeration representing different encoding modes for Protocol Buffers encoding.
+ */
+public enum ProtobufEncodingMode {
+  /**
+   * In this encoding mode, the converter uses a non-standard protobuf encoding to allow boxed types
+   * (e.g., Integer, Double) and String to be nullable. This encoding mode is intended for use when
+   * communicating with another Vert.x converter that supports nullable values.
+   */
+  VERTX,
+
+  /**
+   * In this encoding mode, the converter uses the standard protobuf encoding, which is compatible with
+   * Google's protobuf decoder. Null values are not allowed for boxed types and String in this mode.
+   */
+  GOOGLE_COMPATIBLE,
+}
diff --git a/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/DataObjectProtobufGen.java b/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/DataObjectProtobufGen.java
index 876719f7c..a02b2ef22 100644
--- a/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/DataObjectProtobufGen.java
+++ b/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/DataObjectProtobufGen.java
@@ -72,6 +72,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
     writer.print("import java.util.HashMap;\n");
     writer.print("import java.util.Map;\n");
     writer.print("import java.util.Arrays;\n");
+    writer.print("import io.vertx.codegen.protobuf.ProtobufEncodingMode;\n");
     writer.print("import io.vertx.core.json.JsonObject;\n");
     writer.print("import io.vertx.codegen.protobuf.utils.ExpandableIntArray;\n");
     writer.print("import io.vertx.codegen.protobuf.converters.*;\n");
@@ -90,6 +91,29 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
     // fromProto()
     {
       writer.print("  " + visibility + " static void fromProto(CodedInputStream input, " + simpleName + " obj) throws IOException {\n");
+      writer.print("    fromProto(input, obj, ProtobufEncodingMode.VERTX);\n");
+      writer.print("  }\n");
+      writer.print("\n");
+      writer.print("  " + visibility + " static void fromProto(CodedInputStream input, " + simpleName + " obj, ProtobufEncodingMode encodingMode) throws IOException {\n");
+      writer.print("    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;\n");
+      // Compatible Mode
+      {
+        int fieldNumber = 1;
+        writer.print("    if (compatibleMode) {\n");
+        for (PropertyInfo prop : model.getPropertyMap().values()) {
+          ProtoProperty protoProperty = ProtoProperty.getProtoProperty(prop, fieldNumber);
+          ClassKind propKind = prop.getType().getKind();
+          // Only applicable to Boxed type
+          if (!prop.getKind().isList() && !prop.getKind().isMap() && propKind.basic) {
+            String defaultValue = protoProperty.getDefaultValue();
+            if (protoProperty.isBoxedType() && defaultValue != null) {
+              writer.print("      obj." + prop.getSetterMethod() + "(" + defaultValue + ");\n");
+            }
+          }
+          fieldNumber++;
+        }
+        writer.print("    }\n");
+      }
       writer.print("    int tag;\n");
       writer.print("    while ((tag = input.readTag()) != 0) {\n");
       writer.print("      switch (tag) {\n");
@@ -236,35 +260,59 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
         writer.print("        }\n");
       }
       writer.print("      }\n");
-      writer.print("    }\n");
+      writer.print("    } // while loop\n");
       writer.print("  }\n");
       writer.print("\n");
     }
 
     // toProto()
     {
-      writer.print("  public static void toProto(" + simpleName + " obj, CodedOutputStream output) throws IOException {\n");
+      writer.print("  " + visibility + " static void toProto(" + simpleName + " obj, CodedOutputStream output) throws IOException {\n");
+      writer.print("    toProto(obj, output, ProtobufEncodingMode.VERTX);\n");
+      writer.print("  }\n");
+      writer.print("\n");
+      writer.print("  " + visibility + " static void toProto(" + simpleName + " obj, CodedOutputStream output, ProtobufEncodingMode encodingMode) throws IOException {\n");
       writer.print("    ExpandableIntArray cache = new ExpandableIntArray(" + CACHE_INITIAL_CAPACITY + ");\n");
-      writer.print("    " + simpleName + "ProtoConverter.computeSize(obj, cache, 0);\n");
-      writer.print("    " + simpleName + "ProtoConverter.toProto(obj, output, cache, 0);\n");
+      writer.print("    " + simpleName + "ProtoConverter.computeSize(obj, cache, 0, encodingMode);\n");
+      writer.print("    " + simpleName + "ProtoConverter.toProto(obj, output, cache, 0, encodingMode);\n");
       writer.print("  }\n");
       writer.print("\n");
-      writer.print("  " + visibility + " static int toProto(" + simpleName + " obj, CodedOutputStream output, ExpandableIntArray cache, int index) throws IOException {\n");
+      writer.print("  static int toProto(" + simpleName + " obj, CodedOutputStream output, ExpandableIntArray cache, int index, ProtobufEncodingMode encodingMode) throws IOException {\n");
+      writer.print("    boolean compatibleMode = encodingMode == ProtobufEncodingMode.GOOGLE_COMPATIBLE;\n");
       writer.print("    index = index + 1;\n");
       for (PropertyInfo prop : orderedProperties) {
         ClassKind propKind = prop.getType().getKind();
         int fieldNumber = fieldNumbers.get(prop.getName());
         ProtoProperty protoProperty = ProtoProperty.getProtoProperty(prop, fieldNumber);
-        if (protoProperty.isNullable()) {
-          writer.print("    if (obj." + prop.getGetterMethod() + "() != null) {\n");
-        } else {
-          if ("boolean".equals(prop.getType().getName())) {
-            writer.print("    if (obj." + prop.getGetterMethod() + "()) {\n");
+          writer.print("    // " + prop.getName() + "\n");
+          if (!prop.getKind().isList() && !prop.getKind().isMap() && propKind.basic && protoProperty.isBoxedType()) {
+            writer.print("    if (compatibleMode && obj." + prop.getGetterMethod() + "() == null) {\n");
+            writer.print("      throw new IllegalArgumentException(\"Null values are not allowed for boxed types in compatibility mode\");\n");
+            writer.print("    }\n");
+            String javaDataType = prop.getType().getName();
+            String defaultValue = protoProperty.getDefaultValue();
+            if ("java.lang.Boolean".equals(javaDataType) || "Boolean".equals(javaDataType)) {
+              writer.print("    if ((!compatibleMode && obj." + prop.getGetterMethod() + "() != null) || (compatibleMode && !obj." + prop.getGetterMethod() + "())) {\n");
+            } else if ("java.lang.String".equals(javaDataType) || "String".equals(javaDataType)) {
+              writer.print("    if ((!compatibleMode && obj." + prop.getGetterMethod() + "() != null) || (compatibleMode && !obj." + prop.getGetterMethod() + "().isEmpty())) {\n");
+            } else {
+              if (defaultValue != null) {
+                writer.print("    if ((!compatibleMode && obj." + prop.getGetterMethod() + "() != null) || (compatibleMode && obj." + prop.getGetterMethod() + "() != " + defaultValue + ")) {\n");
+              } else {
+                throw new RuntimeException();
+              }
+            }
           } else {
-            writer.print("    if (obj." + prop.getGetterMethod() + "() != 0) {\n");
+            if (protoProperty.isNullable()) {
+              writer.print("    if (obj." + prop.getGetterMethod() + "() != null) {\n");
+            } else {
+              if ("boolean".equals(prop.getType().getName())) {
+                writer.print("    if (obj." + prop.getGetterMethod() + "()) {\n");
+              } else {
+                writer.print("    if (obj." + prop.getGetterMethod() + "() != 0) {\n");
+              }
+            }
           }
-        }
-
         if (prop.getType().getKind() == ClassKind.ENUM) {
           writer.print("      switch (obj." + prop.getGetterMethod() + "()) {\n");
           EnumTypeInfo enumTypeInfo = (EnumTypeInfo) prop.getType();
@@ -305,7 +353,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
                 writer.print("      for (" + protoProperty.getMessage() + " element: obj." + prop.getGetterMethod() + "()) {\n");
                 writer.print("        output.writeUInt32NoTag(" + protoProperty.getTag() + ");\n");
                 writer.print("        output.writeUInt32NoTag(cache.get(index));\n");
-                writer.print("        index = " + protoProperty.getMessage() + "ProtoConverter.toProto(element, output, cache, index);\n");
+                writer.print("        index = " + protoProperty.getMessage() + "ProtoConverter.toProto(element, output, cache, index, encodingMode);\n");
                 writer.print("      }\n");
               }
             }
@@ -363,7 +411,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
                 writer.print("        output.writeString(1, entry.getKey());\n");
                 writer.print("        output.writeUInt32NoTag(18);\n");
                 writer.print("        output.writeUInt32NoTag(elementSize);\n");
-                writer.print("        index = " + protoProperty.getMessage() + "ProtoConverter.toProto(entry.getValue(), output, cache, index);\n");
+                writer.print("        index = " + protoProperty.getMessage() + "ProtoConverter.toProto(entry.getValue(), output, cache, index, encodingMode);\n");
                 writer.print("      }\n");
               }
             }
@@ -379,7 +427,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
               } else {
                 writer.print("      output.writeUInt32NoTag(" + protoProperty.getTag() + ");\n");
                 writer.print("      output.writeUInt32NoTag(cache.get(index));\n");
-                writer.print("      index = " + protoProperty.getMessage() + "ProtoConverter.toProto(obj." + prop.getGetterMethod() + "(), output, cache, index);\n");
+                writer.print("      index = " + protoProperty.getMessage() + "ProtoConverter.toProto(obj." + prop.getGetterMethod() + "(), output, cache, index, encodingMode);\n");
               }
             }
           }
@@ -394,12 +442,16 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
     // computeSize()
     {
       writer.print("  " + visibility + " static int computeSize(" + simpleName + " obj) {\n");
+      writer.print("    return computeSize(obj, ProtobufEncodingMode.VERTX);\n");
+      writer.print("  }\n");
+      writer.print("\n");
+      writer.print("  " + visibility + " static int computeSize(" + simpleName + " obj, ProtobufEncodingMode encodingMode) {\n");
       writer.print("    ExpandableIntArray cache = new ExpandableIntArray(" + CACHE_INITIAL_CAPACITY + ");\n");
-      writer.print("    " + simpleName + "ProtoConverter.computeSize(obj, cache, 0);\n");
+      writer.print("    " + simpleName + "ProtoConverter.computeSize(obj, cache, 0, encodingMode);\n");
       writer.print("    return cache.get(0);\n");
       writer.print("  }\n");
       writer.print("\n");
-      writer.print("  " + visibility + " static int computeSize(" + simpleName + " obj, ExpandableIntArray cache, final int baseIndex) {\n");
+      writer.print("  static int computeSize(" + simpleName + " obj, ExpandableIntArray cache, final int baseIndex, ProtobufEncodingMode encodingMode) {\n");
       writer.print("    int size = 0;\n");
       writer.print("    int index = baseIndex + 1;\n");
       for (PropertyInfo prop : orderedProperties) {
@@ -457,7 +509,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
                 writer.print("        for (" + protoProperty.getMessage() + " element: obj." + prop.getGetterMethod() + "()) {\n");
                 writer.print("          size += CodedOutputStream.computeUInt32SizeNoTag(" + protoProperty.getTag() + ");\n");
                 writer.print("          int savedIndex = index;\n");
-                writer.print("          index = " + protoProperty.getMessage() + "ProtoConverter.computeSize(element, cache, index);\n");
+                writer.print("          index = " + protoProperty.getMessage() + "ProtoConverter.computeSize(element, cache, index, encodingMode);\n");
                 writer.print("          int dataSize = cache.get(savedIndex);\n");
                 writer.print("          size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);\n");
                 writer.print("          size += dataSize;\n");
@@ -506,7 +558,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
                 writer.print("        dataSize += CodedOutputStream.computeStringSize(1, entry.getKey());\n");
                 writer.print("        // value\n");
                 writer.print("        int savedIndex = index;\n");
-                writer.print("        index = " + protoProperty.getMessage() + "ProtoConverter.computeSize(entry.getValue(), cache, index);\n");
+                writer.print("        index = " + protoProperty.getMessage() + "ProtoConverter.computeSize(entry.getValue(), cache, index, encodingMode);\n");
                 writer.print("        int elementSize = cache.get(savedIndex);\n");
                 writer.print("        dataSize += CodedOutputStream.computeInt32SizeNoTag(18);\n");
                 writer.print("        dataSize += CodedOutputStream.computeInt32SizeNoTag(elementSize);\n");
@@ -530,7 +582,7 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
               } else {
                 writer.print("      size += CodedOutputStream.computeUInt32SizeNoTag(" + protoProperty.getTag() + ");\n");
                 writer.print("      int savedIndex = index;\n");
-                writer.print("      index = " + protoProperty.getMessage() + "ProtoConverter.computeSize(obj." + prop.getGetterMethod() + "(), cache, index);\n");
+                writer.print("      index = " + protoProperty.getMessage() + "ProtoConverter.computeSize(obj." + prop.getGetterMethod() + "(), cache, index, encodingMode);\n");
                 writer.print("      int dataSize = cache.get(savedIndex);\n");
                 writer.print("      size += CodedOutputStream.computeUInt32SizeNoTag(dataSize);\n");
                 writer.print("      size += dataSize;\n");
@@ -549,4 +601,17 @@ public String renderProto(DataObjectModel model, int index, int size, Map<String
 
     return buffer.toString();
   }
+
+  private static String getString(PropertyInfo prop) {
+    String javaDataType = prop.getType().getName();
+    String casting = "";
+    if ("java.lang.Short".equals(javaDataType) || "short".equals(javaDataType)) {
+      casting = "(short) ";
+    } else if ("java.lang.Character".equals(javaDataType) || "char".equals(javaDataType)) {
+      casting = "(char) ";
+    } else if ("java.lang.Byte".equals(javaDataType) || "byte".equals(javaDataType)) {
+      casting = "(byte) ";
+    }
+    return casting;
+  }
 }
diff --git a/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/ProtoProperty.java b/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/ProtoProperty.java
index f8a2f17ae..39e16dbdf 100644
--- a/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/ProtoProperty.java
+++ b/vertx-codegen-protobuf/src/main/java/io/vertx/codegen/protobuf/generator/ProtoProperty.java
@@ -13,6 +13,11 @@ public class ProtoProperty {
   private ProtoType protoType;
   // Indicate if field is nullable.
   private boolean isNullable;
+  // Indicate if field is Java boxed type
+  private boolean isBoxedType; // TODO maybe do not belong here
+
+  private String defaultValue;
+
   // Indicate the name of the message of the nested field
   private String message;
   // Indicate the name of the enumeration type
@@ -26,6 +31,8 @@ public static ProtoProperty getProtoProperty(PropertyInfo prop, int fieldNumber)
     ClassKind propKind = prop.getType().getKind();
     ProtoType protoType = null;
     boolean isNullable = determineIsNullable(prop.getType().getName());
+    boolean isBoxedType = determineIsBoxedType(prop.getType().getName());
+    String defaultValue = determineDefaultValue(prop.getType().getName());
     String message = null;
     String enumType = null;
     String builtInProtoType = null;
@@ -77,6 +84,8 @@ public static ProtoProperty getProtoProperty(PropertyInfo prop, int fieldNumber)
     protoProperty.tag = tag;
     protoProperty.protoType = protoType;
     protoProperty.isNullable = isNullable;
+    protoProperty.isBoxedType = isBoxedType;
+    protoProperty.defaultValue = defaultValue;
     protoProperty.enumType = enumType;
     protoProperty.message = message;
     protoProperty.builtInType = builtInProtoType;
@@ -134,6 +143,61 @@ private static boolean determineIsNullable(String javaDataType) {
     }
   }
 
+  private static boolean determineIsBoxedType(String javaDataType) {
+    if ("java.lang.Integer".equals(javaDataType) || "Integer".equals(javaDataType) ||
+      "java.lang.Short".equals(javaDataType) || "Short".equals(javaDataType) ||
+      "java.lang.Long".equals(javaDataType) || "Long".equals(javaDataType) ||
+      "java.lang.Float".equals(javaDataType) || "Float".equals(javaDataType) ||
+      "java.lang.Double".equals(javaDataType) || "Double".equals(javaDataType) ||
+      "java.lang.Boolean".equals(javaDataType) || "Boolean".equals(javaDataType) ||
+      "java.lang.String".equals(javaDataType) || "String".equals(javaDataType)) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  private static String determineDefaultValue(String javaDataType) {
+    switch (javaDataType) {
+      case "java.lang.Integer":
+      case "Integer":
+      case "int":
+        return "0";
+
+      case "java.lang.Short":
+      case "Short":
+      case "short":
+        return "(short)0";
+
+      case "java.lang.Long":
+      case "Long":
+      case "long":
+        return "0L";
+
+      case "java.lang.Float":
+      case "Float":
+      case "float":
+        return "0f";
+
+      case "java.lang.Double":
+      case "Double":
+      case "double":
+        return "0d";
+
+      case "java.lang.Boolean":
+      case "Boolean":
+      case "boolean":
+        return "false";
+
+      case "java.lang.String":
+      case "String":
+        return "\"\"";
+
+      default:
+        return null;
+    }
+  }
+
   // Find out if the data type are io.vertx.protobuf builtin type, return Proto type
   private static String determineBuiltInType(PropertyInfo prop) {
     String javaDataType = prop.getType().getName();
@@ -200,6 +264,14 @@ public boolean isNullable() {
     return isNullable;
   }
 
+  public boolean isBoxedType() {
+    return isBoxedType;
+  }
+
+  public String getDefaultValue() {
+    return defaultValue;
+  }
+
   public String getEnumType() {
     return enumType;
   }
diff --git a/vertx-codegen-protobuf/src/test/java/io/vertx/test/codegen/protobuf/CompatibilityTest.java b/vertx-codegen-protobuf/src/test/java/io/vertx/test/codegen/protobuf/CompatibilityTest.java
new file mode 100644
index 000000000..b36b0f5de
--- /dev/null
+++ b/vertx-codegen-protobuf/src/test/java/io/vertx/test/codegen/protobuf/CompatibilityTest.java
@@ -0,0 +1,157 @@
+package io.vertx.test.codegen.protobuf;
+
+import com.google.protobuf.CodedInputStream;
+import com.google.protobuf.CodedOutputStream;
+import com.google.protobuf.InvalidProtocolBufferException;
+import io.vertx.codegen.protobuf.ProtobufEncodingMode;
+import io.vertx.test.codegen.converter.SimplePojo;
+import io.vertx.test.codegen.converter.SimplePojoProtoConverter;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+
+public class CompatibilityTest {
+  @Test
+  public void testVertxNullable() throws IOException {
+    // Populate a POJO
+    SimplePojo pojo = new SimplePojo();
+    pojo.setIntegerField(null);
+    pojo.setLongField(null);
+    pojo.setBooleanField(null);
+    pojo.setStringField(null);
+
+    // Vertx Encode
+    byte[] encoded = vertxEncode(pojo, ProtobufEncodingMode.VERTX);
+
+    // Vertx Decode
+    SimplePojo decoded = vertxDecode(encoded, ProtobufEncodingMode.VERTX);
+
+    // Decoded is exactly the same with original pojo
+    Assert.assertEquals(pojo, decoded);
+
+    Assert.assertNull(decoded.getIntegerField());
+    Assert.assertNull(decoded.getLongField());
+    Assert.assertNull(decoded.getStringField());
+    Assert.assertNull(decoded.getBooleanField());
+
+    // Assert total size is equal to computed size
+    Assert.assertEquals(encoded.length, SimplePojoProtoConverter.computeSize(pojo));
+  }
+
+  @Test
+  public void testEncodeNullFieldInCompatibleMode() throws IOException {
+    // Populate a POJO
+    SimplePojo pojo = new SimplePojo();
+    pojo.setIntegerField(null);
+    pojo.setLongField(null);
+    pojo.setBooleanField(null);
+    pojo.setStringField(null);
+
+    // Null field are not allowed in Google Compatible mode
+    try {
+      vertxEncode(pojo, ProtobufEncodingMode.GOOGLE_COMPATIBLE);
+    } catch (IllegalArgumentException e) {
+      Assert.assertEquals("Null values are not allowed for boxed types in compatibility mode", e.getMessage());
+    }
+  }
+
+  @Test
+  public void testEncodeCompatibleMode() throws IOException {
+    // Populate a POJO
+    SimplePojo pojo = new SimplePojo();
+    pojo.setIntegerField(0);
+    pojo.setLongField(0L);
+    pojo.setBooleanField(false);
+    pojo.setStringField("");
+
+    // Vertx Encode
+    byte[] encoded = vertxEncode(pojo, ProtobufEncodingMode.GOOGLE_COMPATIBLE);
+
+    // Protoc Decode
+    io.vertx.protobuf.generated.SimplePojo decoded = protocDecode(encoded);
+
+    Assert.assertEquals(0, decoded.getIntegerField());
+    Assert.assertEquals(0, decoded.getLongField());
+    Assert.assertFalse(decoded.getBooleanField());
+    Assert.assertEquals("", decoded.getStringField());
+  }
+
+  @Test
+  public void testDecodeCompatibleMode() throws IOException {
+    // Populate a Protoc generated POJO
+    io.vertx.protobuf.generated.SimplePojo pojo = io.vertx.protobuf.generated.SimplePojo.newBuilder()
+      .setIntegerField(0)
+      .setLongField(0L)
+      .setBooleanField(false)
+      .setStringField("")
+      .build();
+
+    // Protoc Encode
+    byte[] encoded = protocEncode(pojo);
+
+    // Vertx Decode
+    SimplePojo decoded = vertxDecode(encoded, ProtobufEncodingMode.GOOGLE_COMPATIBLE);
+
+    Assert.assertEquals((Integer)0, decoded.getIntegerField());
+    Assert.assertEquals((Long)0L, decoded.getLongField());
+    Assert.assertEquals(false, decoded.getBooleanField());
+    Assert.assertEquals("", decoded.getStringField());
+  }
+
+  // This test case demonstrates what happens when we decode data from Google Protocol Buffers without using Compatible mode
+  @Test
+  public void testDecodeProtocUsingVertxNullable() throws IOException {
+    // Populate a Protoc generated POJO
+    io.vertx.protobuf.generated.SimplePojo pojo = io.vertx.protobuf.generated.SimplePojo.newBuilder()
+      .setIntegerField(0)
+      .setLongField(0L)
+      .setBooleanField(false)
+      .setStringField("")
+      .build();
+
+    // Protoc Encode
+    byte[] encoded = protocEncode(pojo);
+
+    // Vertx Decode
+    SimplePojo decoded = vertxDecode(encoded, ProtobufEncodingMode.VERTX);
+
+    Assert.assertNull(decoded.getIntegerField()); // Should be 0, but become null due to wrong mode being used
+    Assert.assertNull(decoded.getLongField()); // Should be 0, but become null due to wrong mode being used
+    Assert.assertNull(decoded.getBooleanField()); // Should be false, but become null due to wrong mode being used
+    Assert.assertNull(decoded.getStringField()); // Should be empty string, but become null due to wrong mode being used
+  }
+
+  private byte[] vertxEncode(SimplePojo obj, ProtobufEncodingMode encodingMode) throws IOException {
+    ByteArrayOutputStream baos = new ByteArrayOutputStream();
+    CodedOutputStream output = CodedOutputStream.newInstance(baos);
+    SimplePojoProtoConverter.toProto(obj, output, encodingMode);
+    output.flush();
+    byte[] encoded = baos.toByteArray();
+    TestUtils.debug("Vertx encoded", encoded);
+    return encoded;
+  }
+
+  private byte[] protocEncode(io.vertx.protobuf.generated.SimplePojo obj) throws IOException {
+    ByteArrayOutputStream baos = new ByteArrayOutputStream();
+    CodedOutputStream output = CodedOutputStream.newInstance(baos);
+    obj.writeTo(output);
+    output.flush();
+    byte[] encoded = baos.toByteArray();
+    TestUtils.debug("Protoc encoded", encoded);
+    return encoded;
+  }
+
+  private io.vertx.protobuf.generated.SimplePojo protocDecode(byte[] arr) throws InvalidProtocolBufferException {
+    return io.vertx.protobuf.generated.SimplePojo.parseFrom(arr);
+  }
+
+  private SimplePojo vertxDecode(byte[] arr, ProtobufEncodingMode encodingMode) throws IOException {
+    CodedInputStream input = CodedInputStream.newInstance(arr);
+    SimplePojo obj = new SimplePojo();
+    SimplePojoProtoConverter.fromProto(input, obj, encodingMode);
+    return obj;
+  }
+}