diff --git a/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModel.java b/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModel.java
index cd8bdb78ebf..0897cc77290 100644
--- a/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModel.java
+++ b/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModel.java
@@ -50,7 +50,15 @@ public JsonNodeModel(Object workflowdata) {
         this(null, workflowdata);
     }
 
+    public JsonNodeModel(Object workflowdata, Map<String, Object> additionalProperties) {
+        this(null, workflowdata, additionalProperties);
+    }
+
     public JsonNodeModel(String id, Object workflowdata) {
+        this(id, workflowdata, Collections.emptyMap());
+    }
+
+    public JsonNodeModel(String id, Object workflowdata, Map<String, Object> additionalProperties) {
         this.id = id;
         if (workflowdata instanceof JsonNode) {
             this.workflowdata = (JsonNode) workflowdata;
@@ -59,6 +67,7 @@ public JsonNodeModel(String id, Object workflowdata) {
             this.workflowdata = workflowdata == null ? mapper.createObjectNode() : mapper.convertValue(workflowdata, JsonNode.class);
         }
         this.input = this.workflowdata.deepCopy();
+        this.additionalProperties = additionalProperties == null ? Collections.emptyMap() : additionalProperties;
     }
 
     public String getId() {
diff --git a/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModelInput.java b/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModelInput.java
index 98adedb04f5..d53aa9ea777 100644
--- a/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModelInput.java
+++ b/kogito-serverless-workflow/kogito-serverless-workflow-runtime/src/main/java/org/kie/kogito/serverless/workflow/models/JsonNodeModelInput.java
@@ -18,20 +18,23 @@
  */
 package org.kie.kogito.serverless.workflow.models;
 
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
 import org.kie.kogito.MapInput;
 import org.kie.kogito.MapInputId;
 import org.kie.kogito.MapOutput;
 import org.kie.kogito.MappableToModel;
 import org.kie.kogito.Model;
-import org.kie.kogito.jackson.utils.ObjectMapperFactory;
 
 import com.fasterxml.jackson.annotation.JsonAnySetter;
 import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.node.ObjectNode;
 
 public class JsonNodeModelInput implements Model, MapInput, MapInputId, MapOutput, MappableToModel<JsonNodeModel> {
 
     private Object workflowdata;
+    private Map<String, Object> additionalProperties;
 
     public Object getWorkflowdata() {
         return workflowdata;
@@ -39,16 +42,18 @@ public Object getWorkflowdata() {
 
     @JsonAnySetter
     public void setData(String key, JsonNode value) {
-        if (workflowdata == null) {
-            workflowdata = ObjectMapperFactory.listenerAware().createObjectNode();
-        }
-        if (workflowdata instanceof ObjectNode) {
-            ((ObjectNode) workflowdata).set(key, value);
+        if (additionalProperties == null) {
+            additionalProperties = new LinkedHashMap<>();
         }
+        additionalProperties.put(key, value);
     }
 
     @Override
     public JsonNodeModel toModel() {
-        return new JsonNodeModel(workflowdata);
+        if (workflowdata == null) {
+            workflowdata = additionalProperties;
+            additionalProperties = Collections.emptyMap();
+        }
+        return new JsonNodeModel(workflowdata, additionalProperties);
     }
 }
diff --git a/quarkus/extensions/kogito-quarkus-serverless-workflow-extension/kogito-quarkus-serverless-workflow-integration-test/src/test/java/org/kie/kogito/quarkus/workflows/ExpressionRestIT.java b/quarkus/extensions/kogito-quarkus-serverless-workflow-extension/kogito-quarkus-serverless-workflow-integration-test/src/test/java/org/kie/kogito/quarkus/workflows/ExpressionRestIT.java
index d6d4122929d..5f0b44234a8 100644
--- a/quarkus/extensions/kogito-quarkus-serverless-workflow-extension/kogito-quarkus-serverless-workflow-integration-test/src/test/java/org/kie/kogito/quarkus/workflows/ExpressionRestIT.java
+++ b/quarkus/extensions/kogito-quarkus-serverless-workflow-extension/kogito-quarkus-serverless-workflow-integration-test/src/test/java/org/kie/kogito/quarkus/workflows/ExpressionRestIT.java
@@ -38,7 +38,7 @@ void testExpressionRest() {
                 .contentType(ContentType.JSON)
                 .accept(ContentType.JSON)
                 .header("pepe", "pepa")
-                .body("{\"workflowdata\":{\"numbers\":[{\"x\":2, \"y\": 1},{\"x\":4, \"y\": 3}]}}").when()
+                .body("{\"workflowdata\":{\"numbers\":[{\"x\":2, \"y\": 1},{\"x\":4, \"y\": 3}]}, \"randomAdditionalProperty\":\"Im ignored in runtimes but will be visible on data index\"}").when()
                 .post("/expression")
                 .then()
                 .statusCode(201)