facebook · rubennorte · Mar 4, 2026
diff --git a/packages/react-native/React/Fabric/RCTConversions.h b/packages/react-native/React/Fabric/RCTConversions.h
@@ -13,9 +13,28 @@
 #import <react/renderer/graphics/Color.h>
 #import <react/renderer/graphics/RCTPlatformColorUtils.h>
 #import <react/renderer/graphics/Transform.h>
+#import <react/timing/primitives.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
+/*
+ * Converts an iOS timestamp (seconds since boot, NOT including sleep time, from
+ * NSProcessInfo.processInfo.systemUptime or UITouch.timestamp) to a HighResTimeStamp.
+ *
+ * iOS timestamps use mach_absolute_time() which doesn't account for sleep time,
+ * while std::chrono::steady_clock uses mach_continuous_time() which does.
+ * To handle this correctly, we compute the relative offset from the current time
+ * and apply it to HighResTimeStamp::now().
+ */
+inline facebook::react::HighResTimeStamp RCTHighResTimeStampFromSeconds(NSTimeInterval seconds)
+{
+  NSTimeInterval nowSystemUptime = NSProcessInfo.processInfo.systemUptime;
+  NSTimeInterval delta = nowSystemUptime - seconds;
+  auto deltaDuration =
+      std::chrono::duration_cast<std::chrono::steady_clock::duration>(std::chrono::duration<double>(delta));
+  return facebook::react::HighResTimeStamp::now() - facebook::react::HighResDuration::fromChrono(deltaDuration);
+}
+
 inline NSString *RCTNSStringFromString(
     const std::string &string,
     const NSStringEncoding &encoding = NSUTF8StringEncoding)

diff --git a/packages/react-native/React/Fabric/RCTSurfacePointerHandler.mm b/packages/react-native/React/Fabric/RCTSurfacePointerHandler.mm
@@ -285,6 +285,7 @@ static PointerEvent CreatePointerEventFromActivePointer(
   PointerEvent event = {};
   event.pointerId = activePointer.identifier;
   event.pointerType = PointerTypeCStringFromUITouchType(activePointer.touchType);
+  event.timeStamp = RCTHighResTimeStampFromSeconds(activePointer.timestamp);
 
   if (eventType == RCTPointerEventTypeCancel) {
     event.clientPoint = RCTPointFromCGPoint(CGPointZero);
@@ -345,7 +346,8 @@ static PointerEvent CreatePointerEventFromIncompleteHoverData(
     CGPoint clientLocation,
     CGPoint screenLocation,
     CGPoint offsetLocation,
-    UIKeyModifierFlags modifierFlags)
+    UIKeyModifierFlags modifierFlags,
+    HighResTimeStamp timeStamp)
 {
   PointerEvent event = {};
   event.pointerId = pointerId;
@@ -365,6 +367,7 @@ static PointerEvent CreatePointerEventFromIncompleteHoverData(
   event.tangentialPressure = 0.0;
   event.twist = 0;
   event.isPrimary = true;
+  event.timeStamp = timeStamp;
 
   return event;
 }
@@ -760,8 +763,11 @@ - (void)hovering:(UIHoverGestureRecognizer *)recognizer
 
   modifierFlags = recognizer.modifierFlags;
 
+  // For hover events, use the current time as we don't have a precise timestamp
+  HighResTimeStamp eventTimestamp = HighResTimeStamp::now();
+
   PointerEvent event = CreatePointerEventFromIncompleteHoverData(
-      pointerId, pointerType, clientLocation, screenLocation, offsetLocation, modifierFlags);
+      pointerId, pointerType, clientLocation, screenLocation, offsetLocation, modifierFlags, eventTimestamp);
 
   SharedTouchEventEmitter eventEmitter = GetTouchEmitterFromView(targetView, offsetLocation);
   if (eventEmitter != nil) {

diff --git a/packages/react-native/React/Fabric/RCTSurfaceTouchHandler.mm b/packages/react-native/React/Fabric/RCTSurfaceTouchHandler.mm
@@ -67,6 +67,7 @@ static void UpdateActiveTouchWithUITouch(
   activeTouch.touch.pagePoint = RCTPointFromCGPoint(pagePoint);
 
   activeTouch.touch.timestamp = uiTouch.timestamp;
+  activeTouch.touch.timeStamp = RCTHighResTimeStampFromSeconds(uiTouch.timestamp);
 
   if (RCTForceTouchAvailable()) {
     activeTouch.touch.force = RCTZeroIfNaN(uiTouch.force / uiTouch.maximumPossibleForce);

diff --git a/packages/react-native/ReactAndroid/api/ReactAndroid.api b/packages/react-native/ReactAndroid/api/ReactAndroid.api
@@ -2261,6 +2261,7 @@ public class com/facebook/react/fabric/FabricUIManager : com/facebook/react/brid
 	public fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
 	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;I)V
 	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;IZ)V
+	public fun receiveEvent (IILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;IZJ)V
 	public fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
 	public fun removeUIManagerEventListener (Lcom/facebook/react/bridge/UIManagerListener;)V
 	public fun resolveCustomDirectEventName (Ljava/lang/String;)Ljava/lang/String;
@@ -2287,6 +2288,7 @@ public final class com/facebook/react/fabric/mounting/SurfaceMountingManager {
 	public final fun attachRootView (Landroid/view/View;Lcom/facebook/react/uimanager/ThemedReactContext;)V
 	public final fun deleteView (I)V
 	public final fun enqueuePendingEvent (ILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;I)V
+	public final fun enqueuePendingEvent (ILjava/lang/String;ZLcom/facebook/react/bridge/WritableMap;IJ)V
 	public final fun getContext ()Lcom/facebook/react/uimanager/ThemedReactContext;
 	public final fun getSurfaceId ()I
 	public final fun getView (I)Landroid/view/View;
@@ -4804,11 +4806,13 @@ public final class com/facebook/react/uimanager/events/RCTEventEmitter$DefaultIm
 public abstract interface class com/facebook/react/uimanager/events/RCTModernEventEmitter : com/facebook/react/uimanager/events/RCTEventEmitter {
 	public abstract fun receiveEvent (IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
 	public abstract fun receiveEvent (IILjava/lang/String;ZILcom/facebook/react/bridge/WritableMap;I)V
+	public abstract fun receiveEvent (IILjava/lang/String;ZILcom/facebook/react/bridge/WritableMap;IJ)V
 	public abstract fun receiveEvent (ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
 }
 
 public final class com/facebook/react/uimanager/events/RCTModernEventEmitter$DefaultImpls {
 	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;IILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
+	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;IILjava/lang/String;ZILcom/facebook/react/bridge/WritableMap;IJ)V
 	public static fun receiveEvent (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;ILjava/lang/String;Lcom/facebook/react/bridge/WritableMap;)V
 	public static fun receiveTouches (Lcom/facebook/react/uimanager/events/RCTModernEventEmitter;Ljava/lang/String;Lcom/facebook/react/bridge/WritableArray;Lcom/facebook/react/bridge/WritableArray;)V
 }

diff --git a/...act-native/ReactAndroid/src/main/java/com/facebook/react/animated/EventAnimationDriver.kt b/...act-native/ReactAndroid/src/main/java/com/facebook/react/animated/EventAnimationDriver.kt
@@ -22,6 +22,7 @@ internal class EventAnimationDriver(
     private val eventPath: List<String>,
     @JvmField internal var valueNode: ValueAnimatedNode,
 ) : RCTModernEventEmitter {
+  @Deprecated("Use the overload with eventTimestamp parameter instead.")
   override fun receiveEvent(
       surfaceId: Int,
       targetTag: Int,

diff --git a/...es/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java b/...es/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java
@@ -1067,11 +1067,13 @@ public void updateRootLayoutSpecs(
     return surfaceManager.getView(reactTag);
   }
 
+  @Deprecated
   @Override
   public void receiveEvent(int reactTag, String eventName, @Nullable WritableMap params) {
     receiveEvent(View.NO_ID, reactTag, eventName, false, params, EventCategoryDef.UNSPECIFIED);
   }
 
+  @Deprecated
   @Override
   public void receiveEvent(
       int surfaceId, int reactTag, String eventName, @Nullable WritableMap params) {
@@ -1091,17 +1093,44 @@ public void receiveEvent(
    * @param canCoalesceEvent
    * @param params
    * @param eventCategory
+   * @deprecated Use the overload with eventTimestamp parameter instead.
    */
+  @Deprecated
   public void receiveEvent(
       int surfaceId,
       int reactTag,
       String eventName,
       boolean canCoalesceEvent,
       @Nullable WritableMap params,
       @EventCategoryDef int eventCategory) {
-    receiveEvent(surfaceId, reactTag, eventName, canCoalesceEvent, params, eventCategory, false);
+    receiveEvent(
+        surfaceId,
+        reactTag,
+        eventName,
+        canCoalesceEvent,
+        params,
+        eventCategory,
+        false,
+        SystemClock.uptimeMillis());
   }
 
+  /**
+   * receiveEvent API that emits an event to C++. If {@code canCoalesceEvent} is true, that signals
+   * that C++ may coalesce the event optionally. Otherwise, coalescing can happen in Java before
+   * emitting.
+   *
+   * <p>{@code customCoalesceKey} is currently unused.
+   *
+   * @param surfaceId
+   * @param reactTag
+   * @param eventName
+   * @param canCoalesceEvent
+   * @param params
+   * @param eventCategory
+   * @param experimentalIsSynchronous
+   * @deprecated Use the overload with eventTimestamp parameter instead.
+   */
+  @Deprecated
   @Override
   public void receiveEvent(
       int surfaceId,
@@ -1111,6 +1140,43 @@ public void receiveEvent(
       @Nullable WritableMap params,
       @EventCategoryDef int eventCategory,
       boolean experimentalIsSynchronous) {
+    receiveEvent(
+        surfaceId,
+        reactTag,
+        eventName,
+        canCoalesceEvent,
+        params,
+        eventCategory,
+        experimentalIsSynchronous,
+        SystemClock.uptimeMillis());
+  }
+
+  /**
+   * receiveEvent API that emits an event to C++. If {@code canCoalesceEvent} is true, that signals
+   * that C++ may coalesce the event optionally. Otherwise, coalescing can happen in Java before
+   * emitting.
+   *
+   * <p>{@code customCoalesceKey} is currently unused.
+   *
+   * @param surfaceId
+   * @param reactTag
+   * @param eventName
+   * @param canCoalesceEvent
+   * @param params
+   * @param eventCategory
+   * @param experimentalIsSynchronous
+   * @param eventTimestamp
+   */
+  @Override
+  public void receiveEvent(
+      int surfaceId,
+      int reactTag,
+      String eventName,
+      boolean canCoalesceEvent,
+      @Nullable WritableMap params,
+      @EventCategoryDef int eventCategory,
+      boolean experimentalIsSynchronous,
+      long eventTimestamp) {
 
     if (ReactBuildConfig.DEBUG && surfaceId == View.NO_ID) {
       FLog.d(TAG, "Emitted event without surfaceId: [%d] %s", reactTag, eventName);
@@ -1128,7 +1194,13 @@ public void receiveEvent(
         // access to the event emitter later when the view is mounted. For now just save the event
         // in the view state and trigger it later.
         mMountingManager.enqueuePendingEvent(
-            surfaceId, reactTag, eventName, canCoalesceEvent, params, eventCategory);
+            surfaceId,
+            reactTag,
+            eventName,
+            canCoalesceEvent,
+            params,
+            eventCategory,
+            eventTimestamp);
       } else {
         // This can happen if the view has disappeared from the screen (because of async events)
         FLog.i(TAG, "Unable to invoke event: " + eventName + " for reactTag: " + reactTag);
@@ -1142,13 +1214,13 @@ public void receiveEvent(
       boolean firstEventForFrame =
           mSynchronousEvents.add(new SynchronousEvent(surfaceId, reactTag, eventName));
       if (firstEventForFrame) {
-        eventEmitter.dispatchEventSynchronously(eventName, params);
+        eventEmitter.dispatchEventSynchronously(eventName, params, eventTimestamp);
       }
     } else {
       if (canCoalesceEvent) {
-        eventEmitter.dispatchUnique(eventName, params);
+        eventEmitter.dispatchUnique(eventName, params, eventTimestamp);
       } else {
-        eventEmitter.dispatch(eventName, params, eventCategory);
+        eventEmitter.dispatch(eventName, params, eventCategory, eventTimestamp);
       }
     }
   }

diff --git a/...native/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.kt b/...native/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.kt
@@ -27,33 +27,49 @@ internal class EventEmitterWrapper private constructor() : HybridClassBase() {
       eventName: String,
       params: NativeMap?,
       @EventCategoryDef category: Int,
+      eventTimestamp: Long,
   )
 
-  private external fun dispatchEventSynchronously(eventName: String, params: NativeMap?)
+  private external fun dispatchEventSynchronously(
+      eventName: String,
+      params: NativeMap?,
+      eventTimestamp: Long,
+  )
 
-  private external fun dispatchUniqueEvent(eventName: String, params: NativeMap?)
+  private external fun dispatchUniqueEvent(
+      eventName: String,
+      params: NativeMap?,
+      eventTimestamp: Long,
+  )
 
   /**
    * Invokes the execution of the C++ EventEmitter.
    *
    * @param eventName [String] name of the event to execute.
    * @param params [WritableMap] payload of the event
+   * @param eventCategory event category
+   * @param eventTimestamp timestamp when the event was triggered (in milliseconds since boot)
    */
   @Synchronized
-  fun dispatch(eventName: String, params: WritableMap?, @EventCategoryDef eventCategory: Int) {
+  fun dispatch(
+      eventName: String,
+      params: WritableMap?,
+      @EventCategoryDef eventCategory: Int,
+      eventTimestamp: Long,
+  ) {
     if (!isValid) {
       return
     }
-    dispatchEvent(eventName, params as NativeMap?, eventCategory)
+    dispatchEvent(eventName, params as NativeMap?, eventCategory, eventTimestamp)
   }
 
   @Synchronized
-  fun dispatchEventSynchronously(eventName: String, params: WritableMap?) {
+  fun dispatchEventSynchronously(eventName: String, params: WritableMap?, eventTimestamp: Long) {
     if (!isValid) {
       return
     }
     UiThreadUtil.assertOnUiThread()
-    dispatchEventSynchronously(eventName, params as NativeMap?)
+    dispatchEventSynchronously(eventName, params as NativeMap?, eventTimestamp)
   }
 
   /**
@@ -62,13 +78,14 @@ internal class EventEmitterWrapper private constructor() : HybridClassBase() {
    *
    * @param eventName [String] name of the event to execute.
    * @param params [WritableMap] payload of the event
+   * @param eventTimestamp timestamp when the event was triggered (in milliseconds since boot)
    */
   @Synchronized
-  fun dispatchUnique(eventName: String, params: WritableMap?) {
+  fun dispatchUnique(eventName: String, params: WritableMap?, eventTimestamp: Long) {
     if (!isValid) {
       return
     }
-    dispatchUniqueEvent(eventName, params as NativeMap?)
+    dispatchUniqueEvent(eventName, params as NativeMap?, eventTimestamp)
   }
 
   @Synchronized

diff --git a/...-native/ReactAndroid/src/main/java/com/facebook/react/fabric/events/FabricEventEmitter.kt b/...-native/ReactAndroid/src/main/java/com/facebook/react/fabric/events/FabricEventEmitter.kt
@@ -7,13 +7,15 @@
 
 package com.facebook.react.fabric.events
 
+import android.os.SystemClock
 import com.facebook.react.bridge.WritableMap
 import com.facebook.react.fabric.FabricUIManager
 import com.facebook.react.uimanager.events.EventCategoryDef
 import com.facebook.react.uimanager.events.RCTModernEventEmitter
 import com.facebook.systrace.Systrace
 
 internal class FabricEventEmitter(private val uiManager: FabricUIManager) : RCTModernEventEmitter {
+  @Deprecated("Use the overload with eventTimestamp parameter instead.")
   override fun receiveEvent(
       surfaceId: Int,
       targetTag: Int,
@@ -22,10 +24,41 @@ internal class FabricEventEmitter(private val uiManager: FabricUIManager) : RCTM
       customCoalesceKey: Int,
       params: WritableMap?,
       @EventCategoryDef category: Int,
+  ) {
+    receiveEvent(
+        surfaceId,
+        targetTag,
+        eventName,
+        canCoalesceEvent,
+        customCoalesceKey,
+        params,
+        category,
+        SystemClock.uptimeMillis(),
+    )
+  }
+
+  override fun receiveEvent(
+      surfaceId: Int,
+      targetTag: Int,
+      eventName: String,
+      canCoalesceEvent: Boolean,
+      customCoalesceKey: Int,
+      params: WritableMap?,
+      @EventCategoryDef category: Int,
+      eventTimestamp: Long,
   ) {
     Systrace.beginSection(Systrace.TRACE_TAG_REACT, "FabricEventEmitter.receiveEvent('$eventName')")
     try {
-      uiManager.receiveEvent(surfaceId, targetTag, eventName, canCoalesceEvent, params, category)
+      uiManager.receiveEvent(
+          surfaceId,
+          targetTag,
+          eventName,
+          canCoalesceEvent,
+          params,
+          category,
+          false,
+          eventTimestamp,
+      )
     } finally {
       Systrace.endSection(Systrace.TRACE_TAG_REACT)
     }