diff --git a/.java-version b/.java-version
index 98d9bcb..aabe6ec 100644
--- a/.java-version
+++ b/.java-version
@@ -1 +1 @@
-17
+21
diff --git a/src/main/java/com/epam/healenium/constants/FieldName.java b/src/main/java/com/epam/healenium/constants/FieldName.java
index 2f5d52c..3037bc8 100644
--- a/src/main/java/com/epam/healenium/constants/FieldName.java
+++ b/src/main/java/com/epam/healenium/constants/FieldName.java
@@ -9,5 +9,7 @@ public class FieldName {
     public static final String CLASSES = "classes";
     public static final String CLASS = "class";
     public static final String OTHER = "other";
+    /** Parent node in the ancestor chain (serialized without children to avoid cycles). */
+    public static final String PARENT = "parent";
 
 }
\ No newline at end of file
diff --git a/src/main/java/com/epam/healenium/converter/NodeDeserializer.java b/src/main/java/com/epam/healenium/converter/NodeDeserializer.java
index 693cc2e..2a88c26 100644
--- a/src/main/java/com/epam/healenium/converter/NodeDeserializer.java
+++ b/src/main/java/com/epam/healenium/converter/NodeDeserializer.java
@@ -9,8 +9,16 @@
 import tools.jackson.databind.JsonNode;
 import tools.jackson.databind.deser.std.StdDeserializer;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
+/**
+ * Deserializes a {@link Node} and restores the ancestor chain from nested {@code parent} objects.
+ * Returns the leaf node with {@code parent} links set (via {@link NodeBuilder#addChild}).
+ */
 @SuppressWarnings("unchecked")
 public class NodeDeserializer extends StdDeserializer<Node> {
 
@@ -21,21 +29,57 @@ public NodeDeserializer() {
     @Override
     public Node deserialize(JsonParser parser, DeserializationContext ctxt) throws JacksonException {
         JsonNode tree = ctxt.readTree(parser);
+        return deserializeLeafWithAncestors(tree, ctxt);
+    }
+
+    private Node deserializeLeafWithAncestors(JsonNode leafTree, DeserializationContext ctxt) throws JacksonException {
+        List<JsonNode> rootToLeaf = new ArrayList<>();
+        for (JsonNode current = leafTree; current != null && !current.isNull() && !current.isMissingNode();
+             current = current.get(FieldName.PARENT)) {
+            rootToLeaf.add(current);
+        }
+        Collections.reverse(rootToLeaf);
+
+        // Build root → leaf so NodeBuilder#build sets parent links on children.
+        Node child = null;
+        for (int i = rootToLeaf.size() - 1; i >= 0; i--) {
+            NodeBuilder builder = toBuilder(rootToLeaf.get(i), ctxt);
+            if (child != null) {
+                builder.addChild(child);
+            }
+            child = builder.build();
+        }
+
+        Node leaf = child;
+        while (leaf != null && leaf.getChildren() != null && !leaf.getChildren().isEmpty()) {
+            leaf = leaf.getChildren().getFirst();
+        }
+        return leaf;
+    }
+
+    private NodeBuilder toBuilder(JsonNode tree, DeserializationContext ctxt) throws JacksonException {
         String tag = ctxt.readTreeAsValue(tree.path(FieldName.TAG), String.class);
         Integer index = ctxt.readTreeAsValue(tree.path(FieldName.INDEX), Integer.class);
         String innerText = ctxt.readTreeAsValue(tree.path(FieldName.INNER_TEXT), String.class);
         String id = ctxt.readTreeAsValue(tree.path(FieldName.ID), String.class);
         String classes = ctxt.readTreeAsValue(tree.path(FieldName.CLASSES), String.class);
         Map<String, String> attributes = ctxt.readTreeAsValue(tree.path(FieldName.OTHER), Map.class);
-        attributes.put(FieldName.ID, id);
-        attributes.put(FieldName.CLASS, classes);
+        if (attributes == null) {
+            attributes = new HashMap<>();
+        } else {
+            attributes = new HashMap<>(attributes);
+        }
+        attributes.put(FieldName.ID, id != null ? id : "");
+        attributes.put(FieldName.CLASS, classes != null ? classes : "");
 
-        return new NodeBuilder()
+        NodeBuilder builder = new NodeBuilder()
                 .setTag(tag)
-                .setIndex(index)
-                .addContent(innerText)
-                .setAttributes(attributes)
-                .build();
+                .setIndex(index != null ? index : 0)
+                .setAttributes(attributes);
+        if (innerText != null) {
+            builder.addContent(innerText);
+        }
+        return builder;
     }
 
 }
diff --git a/src/main/java/com/epam/healenium/converter/NodeSerializer.java b/src/main/java/com/epam/healenium/converter/NodeSerializer.java
index 739a4d1..6cdcd6e 100644
--- a/src/main/java/com/epam/healenium/converter/NodeSerializer.java
+++ b/src/main/java/com/epam/healenium/converter/NodeSerializer.java
@@ -10,6 +10,14 @@
 import tools.jackson.databind.jsontype.TypeSerializer;
 import tools.jackson.databind.ser.std.StdSerializer;
 
+import java.util.Collections;
+import java.util.IdentityHashMap;
+import java.util.Set;
+
+/**
+ * Serializes a {@link Node} including its ancestor chain via nested {@code parent} objects.
+ * Children are intentionally omitted to avoid cycles and oversized payloads.
+ */
 public class NodeSerializer extends StdSerializer<Node> {
 
     public NodeSerializer() {
@@ -27,6 +35,12 @@ public void serializeWithType(Node value, JsonGenerator gen, SerializationContex
 
     @Override
     public void serialize(Node value, JsonGenerator gen, SerializationContext serializers) throws JacksonException {
+        Set<Node> visited = Collections.newSetFromMap(new IdentityHashMap<>());
+        visited.add(value);
+        serializeNode(value, gen, visited);
+    }
+
+    private void serializeNode(Node value, JsonGenerator gen, Set<Node> visited) throws JacksonException {
         gen.writeStartObject();
         gen.writeStringProperty(FieldName.TAG, value.getTag());
         Integer index = value.getIndex();
@@ -39,6 +53,13 @@ public void serialize(Node value, JsonGenerator gen, SerializationContext serial
         gen.writeStringProperty(FieldName.ID, value.getId());
         gen.writeStringProperty(FieldName.CLASSES, String.join(" ", value.getClasses()));
         gen.writePOJOProperty(FieldName.OTHER, value.getOtherAttributes());
+
+        Node parent = value.getParent();
+        if (parent != null && visited.add(parent)) {
+            gen.writeName(FieldName.PARENT);
+            serializeNode(parent, gen, visited);
+        }
+
         gen.writeEndObject();
         gen.flush();
     }
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index e9f1190..519439f 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -98,6 +98,12 @@ logging:
       max-history: 10
       total-size-cap: 100MB
 
+# Healenium healing settings (env aliases used by docker-compose)
+healenium:
+  selector-type: ${SELECTOR_TYPE:cssSelector}
+  score-cap: ${SCORE_CAP:.6}
+  recovery-tries: ${RECOVERY_TRIES:1}
+
 # Proxy service configuration
 proxy:
   service: