diff --git a/include/ureact/detail/observer.inl b/include/ureact/detail/observer.inl
index c8d6fd5..ec23992 100644
--- a/include/ureact/detail/observer.inl
+++ b/include/ureact/detail/observer.inl
@@ -34,7 +34,7 @@ UREACT_FUNC const std::shared_ptr<observer_node>& observer_internals::get_node_p
     return m_node;
 }
 
-UREACT_FUNC node_id observer_internals::get_node_id() const
+UREACT_FUNC core::node_id observer_internals::get_node_id() const
 {
     return m_node->get_node_id();
 }
diff --git a/include/ureact/observer.hpp b/include/ureact/observer.hpp
index df726ad..42dd71f 100644
--- a/include/ureact/observer.hpp
+++ b/include/ureact/observer.hpp
@@ -33,7 +33,7 @@ class UREACT_API observer_internals
     UREACT_WARN_UNUSED_RESULT std::shared_ptr<observer_node>& get_node_ptr();
     UREACT_WARN_UNUSED_RESULT const std::shared_ptr<observer_node>& get_node_ptr() const;
 
-    UREACT_WARN_UNUSED_RESULT node_id get_node_id() const;
+    UREACT_WARN_UNUSED_RESULT core::node_id get_node_id() const;
 
 protected:
     UREACT_WARN_UNUSED_RESULT react_graph& get_graph() const;