diff --git a/src/main/java/org/gcube/informationsystem/base/reference/IdentifiableElement.java b/src/main/java/org/gcube/informationsystem/base/reference/IdentifiableElement.java
index 422a717..4f74562 100644
--- a/src/main/java/org/gcube/informationsystem/base/reference/IdentifiableElement.java
+++ b/src/main/java/org/gcube/informationsystem/base/reference/IdentifiableElement.java
@@ -3,6 +3,8 @@ package org.gcube.informationsystem.base.reference;
 import java.util.UUID;
 
 import org.gcube.com.fasterxml.jackson.annotation.JsonGetter;
+import org.gcube.com.fasterxml.jackson.annotation.JsonInclude;
+import org.gcube.com.fasterxml.jackson.annotation.JsonInclude.Include;
 import org.gcube.com.fasterxml.jackson.annotation.JsonPropertyOrder;
 import org.gcube.com.fasterxml.jackson.annotation.JsonSetter;
 import org.gcube.informationsystem.model.reference.properties.Metadata;
@@ -24,6 +26,7 @@ public interface IdentifiableElement extends Element {
 	@JsonSetter(value = ID_PROPERTY)
 	public void setID(UUID uuid);
 	
+	@JsonInclude(Include.NON_NULL)
 	@JsonGetter(value = METADATA_PROPERTY)
 	public Metadata getMetadata();