diff --git a/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/resource/JsonResource.java b/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/resource/JsonResource.java
index 89057c1..84b08ef 100644
--- a/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/resource/JsonResource.java
+++ b/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/resource/JsonResource.java
@@ -22,6 +22,7 @@
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EPackage;
+import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.resource.Resource;
 
@@ -425,6 +426,75 @@ interface IEObjectHandler {
      */
     Object OPTION_SAVE_FEATURES_ORDER_COMPARATOR = "OPTION_SAVE_FEATURES_ORDER_COMPARATOR"; //$NON-NLS-1$
 
+    /**
+     * An option to provide an ISerializationListener.
+     */
+    String OPTION_SERIALIZATION_LISTENER = "OPTION_SERIALIZATION_LISTENER"; //$NON-NLS-1$
+
+    /**
+     * Used to listen to various events during the serialization.
+     *
+     * @author <a href="mailto:stephane.begaudeau@obeo.fr">Stephane Begaudeau</a>
+     */
+    interface ISerializationListener {
+
+        /**
+         * Called when an entry is added to the namespace header.
+         *
+         * @param nsPrefix
+         *            The prefix of the ePackage added
+         * @param nsURI
+         *            The URI of the ePackage added
+         */
+        void onNsHeaderEntryAdded(String nsPrefix, String nsURI);
+
+        /**
+         * Called when an object is serialized.
+         *
+         * @param eObject
+         *            The EObject serialized
+         * @param jsonElement
+         *            The serialization of the EObject
+         */
+        void onObjectSerialized(EObject eObject, JsonElement jsonElement);
+
+        /**
+         * Called when a proxy to an object located in another resource has been created.
+         *
+         * @param eObject
+         *            The object for which the URI is created
+         * @param eReference
+         *            The reference containing the object
+         * @param uri
+         *            The uri created
+         */
+        void onCrossReferenceURICreated(EObject eObject, EReference eReference, String uri);
+
+        /**
+         * Implementation of the listener which does nothing.
+         *
+         * @author <a href="mailto:stephane.begaudeau@obeo.fr">Stephane Begaudeau</a>
+         */
+        class NoOp implements ISerializationListener {
+
+            @Override
+            public void onNsHeaderEntryAdded(String nsPrefix, String nsURI) {
+                // Do nothing
+            }
+
+            @Override
+            public void onObjectSerialized(EObject eObject, JsonElement jsonElement) {
+                // Do nothing
+            }
+
+            @Override
+            public void onCrossReferenceURICreated(EObject eObject, EReference eReference, String uri) {
+                // Do nothing
+            }
+
+        }
+    }
+
     /**
      * Associate an ID to the {@link EObject}.
      *
@@ -434,4 +504,5 @@ interface IEObjectHandler {
      *            the id
      */
     void setID(EObject eObject, String id);
+
 }
diff --git a/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/utils/GsonEObjectSerializer.java b/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/utils/GsonEObjectSerializer.java
index 87442ab..a22cec8 100644
--- a/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/utils/GsonEObjectSerializer.java
+++ b/bundles/org.eclipse.sirius.emfjson/src/main/java/org/eclipse/sirius/emfjson/utils/GsonEObjectSerializer.java
@@ -65,6 +65,7 @@
 import org.eclipse.sirius.emfjson.resource.JsonResource;
 import org.eclipse.sirius.emfjson.resource.JsonResource.EStructuralFeaturesFilter;
 import org.eclipse.sirius.emfjson.resource.JsonResource.IEObjectHandler;
+import org.eclipse.sirius.emfjson.resource.JsonResource.ISerializationListener;
 import org.eclipse.sirius.emfjson.resource.JsonResource.ResourceEntityHandler;
 import org.eclipse.sirius.emfjson.resource.exception.DanglingHREFException;
 
@@ -127,6 +128,8 @@ public class GsonEObjectSerializer implements JsonSerializer<List<EObject>> {
      */
     private IEObjectHandler eObjectHandler;
 
+    private ISerializationListener serializationListener;
+
     /**
      * The constructor.
      *
@@ -166,7 +169,11 @@ public GsonEObjectSerializer(Resource resource, Map<?, ?> options) {
             this.helper.setExtendedMetaData(this.extendedMetaData);
         }
 
-        this.eObjectHandler = (JsonResource.IEObjectHandler) serializedOptions.get(JsonResource.OPTION_EOBJECT_HANDLER);
+        this.eObjectHandler = (IEObjectHandler) serializedOptions.get(JsonResource.OPTION_EOBJECT_HANDLER);
+        this.serializationListener = (ISerializationListener) serializedOptions.get(JsonResource.OPTION_SERIALIZATION_LISTENER);
+        if (this.serializationListener == null) {
+            this.serializationListener = new ISerializationListener.NoOp();
+        }
 
         this.declareSchemaLocation = Boolean.TRUE.equals(options.get(JsonResource.OPTION_SCHEMA_LOCATION));
 
@@ -236,6 +243,8 @@ private JsonElement createData(EObject eObject) {
             this.eObjectHandler.processSerializedContent(jsonElement, eObject);
         }
 
+        this.serializationListener.onObjectSerialized(eObject, jsonElement);
+
         return jsonElement;
     }
 
@@ -835,6 +844,7 @@ private JsonElement createNsHeader() {
                     List<String> nsPrefixes = this.helper.getPrefixes(ePackage);
                     for (String nsPrefix : nsPrefixes) {
                         jsonObject.add(nsPrefix, new JsonPrimitive(nsURI));
+                        this.serializationListener.onNsHeaderEntryAdded(nsPrefix, nsURI);
                     }
                 }
             }
@@ -1381,7 +1391,7 @@ private JsonElement serializeMultipleNonContainmentEReference(EObject eObject, E
                 break;
             case CROSS_DOC:
                 if (value != null) {
-                    jsonArray.add(new JsonPrimitive(this.saveHref(value, null)));
+                    jsonArray.add(new JsonPrimitive(this.saveHref(value, eReference)));
                 }
                 break;
             default:
@@ -1495,6 +1505,7 @@ private String saveHref(EObject object, EReference eReference) {
             // TODO: element Handler if statement : look at XMLSaveImpl line 2308
             value += href;
         }
+        this.serializationListener.onCrossReferenceURICreated(object, eReference, value);
         return value;
     }
 
@@ -1540,8 +1551,8 @@ private int docKindSingle(EObject eObject, EReference eReference) {
     }
 
     /**
-     * Return the the URI fragment if the pointed resource URI schema is the same of the Resource URI schema. Return the
-     * all URI otherwise.
+     * Return the URI fragment if the pointed resource URI schema is the same of the Resource URI schema. Return the all
+     * URI otherwise.
      *
      * @param pointedResourceUri
      *            the pointed resource URI
diff --git a/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/AbstractEMFJsonTests.java b/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/AbstractEMFJsonTests.java
index 5ff1c6a..589d625 100644
--- a/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/AbstractEMFJsonTests.java
+++ b/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/AbstractEMFJsonTests.java
@@ -34,6 +34,7 @@
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EPackage;
+import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EcorePackage;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.resource.ResourceSet;
@@ -67,6 +68,11 @@ public abstract class AbstractEMFJsonTests {
      */
     protected Map<Object, Object> options = new HashMap<Object, Object>();
 
+    /**
+     * Data saved by the serialization listener.
+     */
+    protected Map<String, Object> listenerData = new HashMap<String, Object>();
+
     /**
      * Returns the path of the folder containing the models used during the tests of this class.
      *
@@ -82,6 +88,8 @@ public abstract class AbstractEMFJsonTests {
      *            The name of the resource to save
      */
     protected void testSave(String resourceName) {
+        this.listenerData.clear();
+
         Resource modelResource = this.getModelResource(resourceName, true);
 
         ResourceSet resourceSet = new ResourceSetImpl();
@@ -104,6 +112,20 @@ protected void testSave(String resourceName) {
             this.options.put(JsonResource.OPTION_PRETTY_PRINTING_INDENT, JsonResource.INDENT_2_SPACES);
             this.options.put(JsonResource.OPTION_SCHEMA_LOCATION, Boolean.TRUE);
 
+            JsonResource.ISerializationListener serializationListener = new JsonResource.ISerializationListener.NoOp() {
+                @Override
+                public void onNsHeaderEntryAdded(String nsPrefix, String nsURI) {
+                    AbstractEMFJsonTests.this.listenerData.put("onNsHeaderEntryAdded", nsPrefix + " - " + nsURI); //$NON-NLS-1$//$NON-NLS-2$
+                }
+
+                @Override
+                public void onCrossReferenceURICreated(EObject eObject, EReference eReference, String uri) {
+                    AbstractEMFJsonTests.this.listenerData.put("onCrossReferenceURICreated", uri); //$NON-NLS-1$
+                }
+            };
+
+            this.options.put(JsonResource.OPTION_SERIALIZATION_LISTENER, serializationListener);
+
             resource.save(outputStream, this.options);
 
             String json = new String(outputStream.toByteArray(), Charset.forName("utf-8")); //$NON-NLS-1$
diff --git a/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/unit/save/NonContainmentReferencesSaveTests.java b/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/unit/save/NonContainmentReferencesSaveTests.java
index 1b1656f..133b115 100644
--- a/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/unit/save/NonContainmentReferencesSaveTests.java
+++ b/tests/org.eclipse.sirius.emfjson.tests/src/main/java/org/eclipse/sirius/emfjson/tests/internal/unit/save/NonContainmentReferencesSaveTests.java
@@ -70,6 +70,8 @@ protected String getRootPath() {
     @Test
     public void testSaveSingleValuedEReference() {
         this.testSave("NodeSingleValueEReference.xmi"); //$NON-NLS-1$
+
+        Assert.assertEquals(this.listenerData.get("onNsHeaderEntryAdded"), "nodes - http://www.obeo.fr/EMFJson"); //$NON-NLS-1$ //$NON-NLS-2$
     }
 
     /**
@@ -105,6 +107,8 @@ public void testSaveLibraryWithBookReferencingItsOwnLibrary() {
     @Test
     public void testSaveLibraryWithBookReferencingLibraries() {
         this.testSave("TestLibraryWithBookReferencingLibraries.xmi"); //$NON-NLS-1$
+
+        Assert.assertEquals(this.listenerData.get("onNsHeaderEntryAdded"), "extlib - http:///org/eclipse/emf/examples/library/extlibrary.ecore/1.0.0"); //$NON-NLS-1$//$NON-NLS-2$
     }
 
     /**
@@ -123,6 +127,8 @@ public void testSaveLibraryWithExternalBookReferencingBranchLibrary() {
     @Test
     public void testSaveLibraryWithExternalBookReferencingLibraries() {
         this.testSave("TestLibraryWithExternalBookReferencingLibraries_Book.xmi"); //$NON-NLS-1$
+
+        Assert.assertEquals(this.listenerData.get("onCrossReferenceURICreated"), "TestLibraryWithExternalBookReferencingLibraries_Library.xmi#/0/@branches.0"); //$NON-NLS-1$//$NON-NLS-2$
     }
 
     /**
@@ -140,6 +146,8 @@ public void testSaveLibraryWithExternalBookReferencingLibrary() {
     @Test
     public void testSaveExternalMultiNonContainmentReferences() {
         this.testSave("TestExternalMultiNonContainmentReferences.ecore"); //$NON-NLS-1$
+
+        Assert.assertEquals(this.listenerData.get("onCrossReferenceURICreated"), "../../../nodes.ecore#//NodeMultipleCustomDataType"); //$NON-NLS-1$//$NON-NLS-2$
     }
 
     /**