diff --git a/ReactCommon/fabric/mounting/BUCK b/ReactCommon/fabric/mounting/BUCK
index 23cf786a2..268c698fb 100644
--- a/ReactCommon/fabric/mounting/BUCK
+++ b/ReactCommon/fabric/mounting/BUCK
@@ -27,6 +27,7 @@ rn_xplat_cxx_library(
     exported_headers = subdir_glob(
         [
             ("", "*.h"),
+            ("stubs", "*.h"),
         ],
         prefix = "react/mounting",
     ),
diff --git a/ReactCommon/fabric/mounting/ShadowTree.cpp b/ReactCommon/fabric/mounting/ShadowTree.cpp
index 391471073..de95a18bf 100644
--- a/ReactCommon/fabric/mounting/ShadowTree.cpp
+++ b/ReactCommon/fabric/mounting/ShadowTree.cpp
@@ -5,6 +5,8 @@
 
 #include "ShadowTree.h"
 
+#include <glog/logging.h>
+
 #include <react/components/root/RootComponentDescriptor.h>
 #include <react/core/LayoutContext.h>
 #include <react/core/LayoutPrimitives.h>
@@ -194,6 +196,20 @@ bool ShadowTree::tryCommit(
     if (revision) {
       *revision = revision_;
     }
+
+#ifdef RN_SHADOW_TREE_INTROSPECTION
+    stubViewTree_.mutate(mutations);
+    auto stubViewTree = stubViewTreeFromShadowNode(*rootShadowNode_);
+    if (stubViewTree_ != stubViewTree) {
+      LOG(ERROR) << "Old tree:"
+                 << "\n"
+                 << oldRootShadowNode->getDebugDescription() << "\n";
+      LOG(ERROR) << "New tree:"
+                 << "\n"
+                 << newRootShadowNode->getDebugDescription() << "\n";
+      assert(false);
+    }
+#endif
   }
 
   emitLayoutEvents(mutations);
diff --git a/ReactCommon/fabric/mounting/ShadowTree.h b/ReactCommon/fabric/mounting/ShadowTree.h
index 09ca34f35..5d5b83edb 100644
--- a/ReactCommon/fabric/mounting/ShadowTree.h
+++ b/ReactCommon/fabric/mounting/ShadowTree.h
@@ -5,6 +5,10 @@
 
 #pragma once
 
+#ifdef DEBUG
+#define RN_SHADOW_TREE_INTROSPECTION
+#endif
+
 #include <better/mutex.h>
 #include <memory>
 
@@ -16,6 +20,10 @@
 #include <react/mounting/ShadowTreeDelegate.h>
 #include <react/mounting/ShadowViewMutation.h>
 
+#ifdef RN_SHADOW_TREE_INTROSPECTION
+#include <react/mounting/stubs.h>
+#endif
+
 namespace facebook {
 namespace react {
 
@@ -87,6 +95,10 @@ class ShadowTree final {
   mutable SharedRootShadowNode rootShadowNode_; // Protected by `commitMutex_`.
   mutable int revision_{1}; // Protected by `commitMutex_`.
   ShadowTreeDelegate const *delegate_;
+
+#ifdef RN_SHADOW_TREE_INTROSPECTION
+  mutable StubViewTree stubViewTree_; // Protected by `commitMutex_`.
+#endif
 };
 
 } // namespace react
diff --git a/ReactCommon/fabric/mounting/stubs/StubView.cpp b/ReactCommon/fabric/mounting/stubs/StubView.cpp
new file mode 100644
index 000000000..5f0adaf01
--- /dev/null
+++ b/ReactCommon/fabric/mounting/stubs/StubView.cpp
@@ -0,0 +1,31 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+#include "StubView.h"
+
+namespace facebook {
+namespace react {
+
+void StubView::update(ShadowView const &shadowView) {
+  componentName = shadowView.componentName;
+  componentHandle = shadowView.componentHandle;
+  tag = shadowView.tag;
+  props = shadowView.props;
+  eventEmitter = shadowView.eventEmitter;
+  layoutMetrics = shadowView.layoutMetrics;
+  state = shadowView.state;
+}
+
+bool operator==(StubView const &lhs, StubView const &rhs) {
+  return std::tie(lhs.props, lhs.layoutMetrics) ==
+      std::tie(rhs.props, rhs.layoutMetrics);
+}
+
+bool operator!=(StubView const &lhs, StubView const &rhs) {
+  return !(lhs == rhs);
+}
+
+} // namespace react
+} // namespace facebook
diff --git a/ReactCommon/fabric/mounting/stubs/StubView.h b/ReactCommon/fabric/mounting/stubs/StubView.h
new file mode 100644
index 000000000..a69598251
--- /dev/null
+++ b/ReactCommon/fabric/mounting/stubs/StubView.h
@@ -0,0 +1,41 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+#pragma once
+
+#include <memory>
+#include <vector>
+
+#include <react/core/LayoutMetrics.h>
+#include <react/core/State.h>
+#include <react/mounting/ShadowView.h>
+
+namespace facebook {
+namespace react {
+
+class StubView final {
+ public:
+  using Shared = std::shared_ptr<StubView>;
+
+  StubView() = default;
+  StubView(StubView const &stubView) = default;
+
+  void update(ShadowView const &shadowView);
+
+  ComponentName componentName;
+  ComponentHandle componentHandle;
+  Tag tag;
+  SharedProps props;
+  SharedEventEmitter eventEmitter;
+  LayoutMetrics layoutMetrics;
+  State::Shared state;
+  std::vector<StubView::Shared> children;
+};
+
+bool operator==(StubView const &lhs, StubView const &rhs);
+bool operator!=(StubView const &lhs, StubView const &rhs);
+
+} // namespace react
+} // namespace facebook
diff --git a/ReactCommon/fabric/mounting/stubs/StubViewTree.cpp b/ReactCommon/fabric/mounting/stubs/StubViewTree.cpp
new file mode 100644
index 000000000..a6152c084
--- /dev/null
+++ b/ReactCommon/fabric/mounting/stubs/StubViewTree.cpp
@@ -0,0 +1,104 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+#include "StubViewTree.h"
+
+namespace facebook {
+namespace react {
+
+StubViewTree::StubViewTree(ShadowView const &shadowView) {
+  auto view = std::make_shared<StubView>();
+  view->update(shadowView);
+  registry[shadowView.tag] = view;
+}
+
+void StubViewTree::mutate(ShadowViewMutationList const &mutations) {
+  for (auto const &mutation : mutations) {
+    switch (mutation.type) {
+      case ShadowViewMutation::Create: {
+        assert(mutation.parentShadowView == ShadowView{});
+        assert(mutation.oldChildShadowView == ShadowView{});
+        auto stubView = std::make_shared<StubView>();
+        auto tag = mutation.newChildShadowView.tag;
+        assert(registry.find(tag) == registry.end());
+        registry[tag] = stubView;
+        break;
+      }
+
+      case ShadowViewMutation::Delete: {
+        assert(mutation.parentShadowView == ShadowView{});
+        assert(mutation.newChildShadowView == ShadowView{});
+        auto tag = mutation.oldChildShadowView.tag;
+        assert(registry.find(tag) != registry.end());
+        registry.erase(tag);
+        break;
+      }
+
+      case ShadowViewMutation::Insert: {
+        assert(mutation.oldChildShadowView == ShadowView{});
+        auto parentTag = mutation.parentShadowView.tag;
+        assert(registry.find(parentTag) != registry.end());
+        auto parentStubView = registry[parentTag];
+        auto childTag = mutation.newChildShadowView.tag;
+        assert(registry.find(childTag) != registry.end());
+        auto childStubView = registry[childTag];
+        childStubView->update(mutation.newChildShadowView);
+        parentStubView->children.insert(
+            parentStubView->children.begin() + mutation.index, childStubView);
+        break;
+      }
+
+      case ShadowViewMutation::Remove: {
+        assert(mutation.newChildShadowView == ShadowView{});
+        auto parentTag = mutation.parentShadowView.tag;
+        assert(registry.find(parentTag) != registry.end());
+        auto parentStubView = registry[parentTag];
+        auto childTag = mutation.oldChildShadowView.tag;
+        assert(registry.find(childTag) != registry.end());
+        auto childStubView = registry[childTag];
+        assert(
+            parentStubView->children[mutation.index]->tag ==
+            childStubView->tag);
+        parentStubView->children.erase(
+            parentStubView->children.begin() + mutation.index);
+        break;
+      }
+
+      case ShadowViewMutation::Update: {
+        assert(
+            mutation.newChildShadowView.tag == mutation.oldChildShadowView.tag);
+        assert(
+            registry.find(mutation.newChildShadowView.tag) != registry.end());
+        auto stubView = registry[mutation.newChildShadowView.tag];
+        stubView->update(mutation.newChildShadowView);
+        break;
+      }
+    }
+  }
+}
+
+bool operator==(StubViewTree const &lhs, StubViewTree const &rhs) {
+  if (lhs.registry.size() != rhs.registry.size()) {
+    return false;
+  }
+
+  for (auto const &pair : lhs.registry) {
+    auto &lhsStubView = *lhs.registry.at(pair.first);
+    auto &rhsStubView = *rhs.registry.at(pair.first);
+
+    if (lhsStubView != rhsStubView) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool operator!=(StubViewTree const &lhs, StubViewTree const &rhs) {
+  return !(lhs == rhs);
+}
+
+} // namespace react
+} // namespace facebook
diff --git a/ReactCommon/fabric/mounting/stubs/StubViewTree.h b/ReactCommon/fabric/mounting/stubs/StubViewTree.h
new file mode 100644
index 000000000..59f112b89
--- /dev/null
+++ b/ReactCommon/fabric/mounting/stubs/StubViewTree.h
@@ -0,0 +1,31 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+#pragma once
+
+#include <memory>
+#include <unordered_map>
+
+#include <react/mounting/ShadowViewMutation.h>
+#include <react/mounting/StubView.h>
+
+namespace facebook {
+namespace react {
+
+class StubViewTree {
+ public:
+  StubViewTree() = default;
+  StubViewTree(ShadowView const &shadowView);
+
+  void mutate(ShadowViewMutationList const &mutations);
+
+  std::unordered_map<Tag, StubView::Shared> registry{};
+};
+
+bool operator==(StubViewTree const &lhs, StubViewTree const &rhs);
+bool operator!=(StubViewTree const &lhs, StubViewTree const &rhs);
+
+} // namespace react
+} // namespace facebook
diff --git a/ReactCommon/fabric/mounting/stubs/stubs.cpp b/ReactCommon/fabric/mounting/stubs/stubs.cpp
new file mode 100644
index 000000000..48c609c32
--- /dev/null
+++ b/ReactCommon/fabric/mounting/stubs/stubs.cpp
@@ -0,0 +1,30 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+#include "stubs.h"
+
+#include <react/core/LayoutableShadowNode.h>
+#include <react/core/ShadowNodeFragment.h>
+#include <react/mounting/Differentiator.h>
+
+namespace facebook {
+namespace react {
+
+StubViewTree stubViewTreeFromShadowNode(ShadowNode const &rootShadowNode) {
+  auto emptyRootShadowNode = rootShadowNode.clone(
+      ShadowNodeFragment{ShadowNodeFragment::tagPlaceholder(),
+                         ShadowNodeFragment::surfaceIdPlaceholder(),
+                         ShadowNodeFragment::propsPlaceholder(),
+                         ShadowNodeFragment::eventEmitterPlaceholder(),
+                         ShadowNode::emptySharedShadowNodeSharedList()});
+
+  auto stubViewTree = StubViewTree(ShadowView(*emptyRootShadowNode));
+  stubViewTree.mutate(
+      calculateShadowViewMutations(*emptyRootShadowNode, rootShadowNode));
+  return stubViewTree;
+}
+
+} // namespace react
+} // namespace facebook
diff --git a/ReactCommon/fabric/mounting/stubs/stubs.h b/ReactCommon/fabric/mounting/stubs/stubs.h
new file mode 100644
index 000000000..f02c5a2e6
--- /dev/null
+++ b/ReactCommon/fabric/mounting/stubs/stubs.h
@@ -0,0 +1,18 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+#pragma once
+
+#include <react/core/ShadowNode.h>
+#include "StubView.h"
+#include "StubViewTree.h"
+
+namespace facebook {
+namespace react {
+
+StubViewTree stubViewTreeFromShadowNode(ShadowNode const &rootShadowNode);
+
+} // namespace react
+} // namespace facebook