diff --git a/React/Fabric/Mounting/RCTMountingManager.h b/React/Fabric/Mounting/RCTMountingManager.h
new file mode 100644
index 000000000..bf66ac7f5
--- /dev/null
+++ b/React/Fabric/Mounting/RCTMountingManager.h
@@ -0,0 +1,35 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import <fabric/uimanager/TreeMutationInstruction.h>
+#import <React/RCTPrimitives.h>
+#import <React/RCTMountingManagerDelegate.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class RCTComponentViewRegistry;
+
+/**
+ * Manages mounting process.
+ */
+@interface RCTMountingManager : NSObject
+
+@property (nonatomic, weak) id <RCTMountingManagerDelegate> delegate;
+@property (nonatomic, strong) RCTComponentViewRegistry *componentViewRegistry;
+
+/**
+ * Transfroms mutation insturctions to mount items and execute them.
+ * The order of mutation tnstructions matters.
+ */
+- (void)mutateComponentViewTreeWithMutationInstructions:(facebook::react::TreeMutationInstructionList)instructions
+                                                rootTag:(ReactTag)rootTag;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/React/Fabric/Mounting/RCTMountingManager.mm b/React/Fabric/Mounting/RCTMountingManager.mm
new file mode 100644
index 000000000..5f16ac251
--- /dev/null
+++ b/React/Fabric/Mounting/RCTMountingManager.mm
@@ -0,0 +1,152 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTMountingManager.h"
+
+#import <fabric/core/LayoutableShadowNode.h>
+#import <React/RCTAssert.h>
+#import <React/RCTUtils.h>
+
+#import "RCTComponentViewProtocol.h"
+#import "RCTComponentViewRegistry.h"
+#import "RCTMountItemProtocol.h"
+
+#import "RCTCreateMountItem.h"
+#import "RCTDeleteMountItem.h"
+#import "RCTInsertMountItem.h"
+#import "RCTRemoveMountItem.h"
+#import "RCTUpdatePropsMountItem.h"
+#import "RCTUpdateLayoutMetricsMountItem.h"
+
+using namespace facebook::react;
+
+@implementation RCTMountingManager
+
+- (instancetype)init
+{
+  if (self = [super init]) {
+    _componentViewRegistry = [[RCTComponentViewRegistry alloc] init];
+  }
+
+  return self;
+}
+
+- (void)mutateComponentViewTreeWithMutationInstructions:(facebook::react::TreeMutationInstructionList)instructions
+                                                rootTag:(ReactTag)rootTag
+{
+  NSMutableArray<RCTMountItemProtocol> *mountItems =
+    [[NSMutableArray<RCTMountItemProtocol> alloc] initWithCapacity:instructions.size() * 2 /* ~ the worst case */];
+
+  for (auto instruction : instructions) {
+    switch (instruction.getType()) {
+      case TreeMutationInstruction::Creation: {
+        NSString *componentName = [NSString stringWithCString:instruction.getNewChildNode()->getComponentName().c_str()
+                                                     encoding:NSASCIIStringEncoding];
+        RCTCreateMountItem *mountItem =
+          [[RCTCreateMountItem alloc] initWithComponentName:componentName
+                                                        tag:instruction.getNewChildNode()->getTag()];
+        [mountItems addObject:mountItem];
+        break;
+      }
+      case TreeMutationInstruction::Deletion: {
+        NSString *componentName = [NSString stringWithCString:instruction.getOldChildNode()->getComponentName().c_str()
+                                                     encoding:NSASCIIStringEncoding];
+        RCTDeleteMountItem *mountItem =
+          [[RCTDeleteMountItem alloc] initWithComponentName:componentName
+                                                        tag:instruction.getOldChildNode()->getTag()];
+        [mountItems addObject:mountItem];
+        break;
+      }
+
+      case TreeMutationInstruction::Insertion: {
+        RCTInsertMountItem *mountItem =
+          [[RCTInsertMountItem alloc] initWithChildTag:instruction.getNewChildNode()->getTag()
+                                             parentTag:instruction.getParentNode()->getTag()
+                                                 index:instruction.getIndex()];
+        [mountItems addObject:mountItem];
+
+        // Props
+        [mountItems addObject:[[RCTUpdatePropsMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
+                                                                  oldProps:nullptr
+                                                                  newProps:instruction.getNewChildNode()->getProps()]];
+
+        // Layout
+        SharedLayoutableShadowNode layoutableNewShadowNode =
+          std::dynamic_pointer_cast<const LayoutableShadowNode>(instruction.getNewChildNode());
+
+        if (layoutableNewShadowNode) {
+          [mountItems addObject:[[RCTUpdateLayoutMetricsMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
+                                                                    oldLayoutMetrics:{}
+                                                                    newLayoutMetrics:layoutableNewShadowNode->getLayoutMetrics()]];
+        }
+        break;
+      }
+
+      case TreeMutationInstruction::Removal: {
+        RCTRemoveMountItem *mountItem =
+          [[RCTRemoveMountItem alloc] initWithChildTag:instruction.getOldChildNode()->getTag()
+                                             parentTag:instruction.getParentNode()->getTag()
+                                                 index:instruction.getIndex()];
+        [mountItems addObject:mountItem];
+        break;
+      }
+
+      case TreeMutationInstruction::Replacement: {
+        SharedShadowNode oldShadowNode = instruction.getOldChildNode();
+        SharedShadowNode newShadowNode = instruction.getNewChildNode();
+
+        // Props
+        if (oldShadowNode->getProps() != newShadowNode->getProps()) {
+          RCTUpdatePropsMountItem *mountItem =
+            [[RCTUpdatePropsMountItem alloc] initWithTag:instruction.getOldChildNode()->getTag()
+                                                oldProps:instruction.getOldChildNode()->getProps()
+                                                newProps:instruction.getNewChildNode()->getProps()];
+          [mountItems addObject:mountItem];
+        }
+
+        // Layout
+        SharedLayoutableShadowNode layoutableOldShadowNode =
+          std::dynamic_pointer_cast<const LayoutableShadowNode>(oldShadowNode);
+
+        if (layoutableOldShadowNode) {
+          SharedLayoutableShadowNode layoutableNewShadowNode =
+            std::dynamic_pointer_cast<const LayoutableShadowNode>(newShadowNode);
+
+          if (layoutableOldShadowNode->getLayoutMetrics() != layoutableNewShadowNode->getLayoutMetrics()) {
+            RCTUpdateLayoutMetricsMountItem *mountItem =
+              [[RCTUpdateLayoutMetricsMountItem alloc] initWithTag:instruction.getOldChildNode()->getTag()
+                                                  oldLayoutMetrics:layoutableOldShadowNode->getLayoutMetrics()
+                                                  newLayoutMetrics:layoutableNewShadowNode->getLayoutMetrics()];
+            [mountItems addObject:mountItem];
+          }
+        }
+
+        break;
+      }
+    }
+  }
+
+  RCTExecuteOnMainQueue(^{
+    [self _performMountItems:mountItems rootTag:rootTag];
+  });
+}
+
+- (void)_performMountItems:(NSArray<RCTMountItemProtocol> *)mountItems
+                   rootTag:(ReactTag)rootTag
+{
+  RCTAssertMainQueue();
+
+  [self.delegate mountingManager:self willMountComponentsWithRootTag:rootTag];
+
+  for (id<RCTMountItemProtocol> mountItem in mountItems) {
+    [mountItem executeWithRegistry:_componentViewRegistry];
+  }
+
+  [self.delegate mountingManager:self didMountComponentsWithRootTag:rootTag];
+}
+
+@end
diff --git a/React/Fabric/Mounting/RCTMountingManagerDelegate.h b/React/Fabric/Mounting/RCTMountingManagerDelegate.h
new file mode 100644
index 000000000..90ef6cecf
--- /dev/null
+++ b/React/Fabric/Mounting/RCTMountingManagerDelegate.h
@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import <React/RCTPrimitives.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class RCTMountingManager;
+
+/**
+ * MountingManager's delegate.
+ */
+@protocol RCTMountingManagerDelegate <NSObject>
+
+/*
+ * Called right *before* execution of mount items which affect a Surface with
+ * given `rootTag`.
+ * Always called on the main queue.
+ */
+- (void)mountingManager:(RCTMountingManager *)mountingManager willMountComponentsWithRootTag:(ReactTag)MountingManager;
+
+/*
+ * Called right *after* execution of mount items which affect a Surface with
+ * given `rootTag`.
+ * Always called on the main queue.
+ */
+- (void)mountingManager:(RCTMountingManager *)mountingManager didMountComponentsWithRootTag:(ReactTag)rootTag;
+
+@end
+
+NS_ASSUME_NONNULL_END