diff --git a/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java b/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java
index 35beffdbb6d..17a2fe11f93 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.java
@@ -9,13 +9,12 @@ package com.facebook.react.animated;
 
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeAnimatedModuleSpec;
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.common.ReactConstants;
@@ -75,7 +74,7 @@ import java.util.ArrayList;
  * while UI thread is "executing" the animation loop.
  */
 @ReactModule(name = NativeAnimatedModule.NAME)
-public class NativeAnimatedModule extends ReactContextBaseJavaModule
+public class NativeAnimatedModule extends NativeAnimatedModuleSpec
     implements LifecycleEventListener, UIManagerModuleListener {
 
   public static final String NAME = "NativeAnimatedModule";
@@ -110,7 +109,7 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
               // and no outstanding tasks on the operations queue. Apparently frame callbacks can
               // only
               // be posted from the UI thread and therefore we cannot schedule them directly from
-              // @ReactMethod methods
+              // @Override
               Assertions.assertNotNull(mReactChoreographer)
                   .postFrameCallback(
                       ReactChoreographer.CallbackType.NATIVE_ANIMATED_MODULE,
@@ -216,8 +215,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
     mNodesManager = nodesManager;
   }
 
-  @ReactMethod
-  public void createAnimatedNode(final int tag, final ReadableMap config) {
+  @Override
+  public void createAnimatedNode(final double tagDouble, final ReadableMap config) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -227,8 +228,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void startListeningToAnimatedNodeValue(final int tag) {
+  @Override
+  public void startListeningToAnimatedNodeValue(final double tagDouble) {
+    final int tag = (int) tagDouble;
+
     final AnimatedNodeValueListener listener =
         new AnimatedNodeValueListener() {
           public void onValueUpdate(double value) {
@@ -255,8 +258,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void stopListeningToAnimatedNodeValue(final int tag) {
+  @Override
+  public void stopListeningToAnimatedNodeValue(final double tagDouble) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -266,8 +271,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void dropAnimatedNode(final int tag) {
+  @Override
+  public void dropAnimatedNode(final double tagDouble) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -277,8 +284,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void setAnimatedNodeValue(final int tag, final double value) {
+  @Override
+  public void setAnimatedNodeValue(final double tagDouble, final double value) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -288,8 +297,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void setAnimatedNodeOffset(final int tag, final double value) {
+  @Override
+  public void setAnimatedNodeOffset(final double tagDouble, final double value) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -299,8 +310,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void flattenAnimatedNodeOffset(final int tag) {
+  @Override
+  public void flattenAnimatedNodeOffset(final double tagDouble) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -310,8 +323,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void extractAnimatedNodeOffset(final int tag) {
+  @Override
+  public void extractAnimatedNodeOffset(final double tagDouble) {
+    final int tag = (int) tagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -321,12 +336,15 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
+  @Override
   public void startAnimatingNode(
-      final int animationId,
-      final int animatedNodeTag,
+      final double animationIdDouble,
+      final double animatedNodeTagDouble,
       final ReadableMap animationConfig,
       final Callback endCallback) {
+    final int animationId = (int) animationIdDouble;
+    final int animatedNodeTag = (int) animatedNodeTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -337,8 +355,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void stopAnimation(final int animationId) {
+  @Override
+  public void stopAnimation(final double animationIdDouble) {
+    final int animationId = (int) animationIdDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -348,8 +368,12 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void connectAnimatedNodes(final int parentNodeTag, final int childNodeTag) {
+  @Override
+  public void connectAnimatedNodes(
+      final double parentNodeTagDouble, final double childNodeTagDouble) {
+    final int parentNodeTag = (int) parentNodeTagDouble;
+    final int childNodeTag = (int) childNodeTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -359,8 +383,12 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void disconnectAnimatedNodes(final int parentNodeTag, final int childNodeTag) {
+  @Override
+  public void disconnectAnimatedNodes(
+      final double parentNodeTagDouble, final double childNodeTagDouble) {
+    final int parentNodeTag = (int) parentNodeTagDouble;
+    final int childNodeTag = (int) childNodeTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -370,8 +398,12 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void connectAnimatedNodeToView(final int animatedNodeTag, final int viewTag) {
+  @Override
+  public void connectAnimatedNodeToView(
+      final double animatedNodeTagDouble, final double viewTagDouble) {
+    final int animatedNodeTag = (int) animatedNodeTagDouble;
+    final int viewTag = (int) viewTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -381,8 +413,12 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void disconnectAnimatedNodeFromView(final int animatedNodeTag, final int viewTag) {
+  @Override
+  public void disconnectAnimatedNodeFromView(
+      final double animatedNodeTagDouble, final double viewTagDouble) {
+    final int animatedNodeTag = (int) animatedNodeTagDouble;
+    final int viewTag = (int) viewTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -392,8 +428,10 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
-  public void restoreDefaultValues(final int animatedNodeTag) {
+  @Override
+  public void restoreDefaultValues(final double animatedNodeTagDouble) {
+    final int animatedNodeTag = (int) animatedNodeTagDouble;
+
     mPreOperations.add(
         new UIThreadOperation() {
           @Override
@@ -403,9 +441,11 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
+  @Override
   public void addAnimatedEventToView(
-      final int viewTag, final String eventName, final ReadableMap eventMapping) {
+      final double viewTagDouble, final String eventName, final ReadableMap eventMapping) {
+    final int viewTag = (int) viewTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -415,9 +455,12 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
         });
   }
 
-  @ReactMethod
+  @Override
   public void removeAnimatedEventFromView(
-      final int viewTag, final String eventName, final int animatedValueTag) {
+      final double viewTagDouble, final String eventName, final double animatedValueTagDouble) {
+    final int viewTag = (int) viewTagDouble;
+    final int animatedValueTag = (int) animatedValueTagDouble;
+
     mOperations.add(
         new UIThreadOperation() {
           @Override
@@ -426,4 +469,14 @@ public class NativeAnimatedModule extends ReactContextBaseJavaModule
           }
         });
   }
+
+  @Override
+  public void addListener(String eventName) {
+    // iOS only
+  }
+
+  @Override
+  public void removeListeners(double count) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/devsupport/JSDevSupport.java b/ReactAndroid/src/main/java/com/facebook/react/devsupport/JSDevSupport.java
index 1130c32e76b..1b3c60f9850 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/devsupport/JSDevSupport.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/devsupport/JSDevSupport.java
@@ -10,16 +10,15 @@ package com.facebook.react.devsupport;
 import android.util.Pair;
 import android.view.View;
 import androidx.annotation.Nullable;
+import com.facebook.fbreact.specs.NativeJSDevSupportSpec;
 import com.facebook.react.bridge.JavaScriptModule;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.module.annotations.ReactModule;
 import java.util.HashMap;
 import java.util.Map;
 
 @ReactModule(name = JSDevSupport.MODULE_NAME)
-public class JSDevSupport extends ReactContextBaseJavaModule {
+public class JSDevSupport extends NativeJSDevSupportSpec {
   public static final String MODULE_NAME = "JSDevSupport";
 
   public static final int ERROR_CODE_EXCEPTION = 0;
@@ -72,7 +71,7 @@ public class JSDevSupport extends ReactContextBaseJavaModule {
   }
 
   @SuppressWarnings("unused")
-  @ReactMethod
+  @Override
   public synchronized void onSuccess(String data) {
     if (mCurrentCallback != null) {
       mCurrentCallback.onSuccess(data);
@@ -80,15 +79,17 @@ public class JSDevSupport extends ReactContextBaseJavaModule {
   }
 
   @SuppressWarnings("unused")
-  @ReactMethod
-  public synchronized void onFailure(int errorCode, String error) {
+  @Override
+  public synchronized void onFailure(double errorCodeDouble, String error) {
+    int errorCode = (int) errorCodeDouble;
+
     if (mCurrentCallback != null) {
       mCurrentCallback.onFailure(errorCode, new RuntimeException(error));
     }
   }
 
   @Override
-  public Map<String, Object> getConstants() {
+  public Map<String, Object> getTypedExportedConstants() {
     HashMap<String, Object> constants = new HashMap<>();
     constants.put("ERROR_CODE_EXCEPTION", ERROR_CODE_EXCEPTION);
     constants.put("ERROR_CODE_VIEW_NOT_FOUND", ERROR_CODE_VIEW_NOT_FOUND);
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/accessibilityinfo/AccessibilityInfoModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/accessibilityinfo/AccessibilityInfoModule.java
index bb7bec2c387..1b8998a5977 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/accessibilityinfo/AccessibilityInfoModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/accessibilityinfo/AccessibilityInfoModule.java
@@ -19,11 +19,10 @@ import android.provider.Settings;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityManager;
 import androidx.annotation.Nullable;
+import com.facebook.fbreact.specs.NativeAccessibilityInfoSpec;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.modules.core.DeviceEventManagerModule;
 
@@ -32,7 +31,7 @@ import com.facebook.react.modules.core.DeviceEventManagerModule;
  * device. For API >= 19.
  */
 @ReactModule(name = AccessibilityInfoModule.NAME)
-public class AccessibilityInfoModule extends ReactContextBaseJavaModule
+public class AccessibilityInfoModule extends NativeAccessibilityInfoSpec
     implements LifecycleEventListener {
 
   public static final String NAME = "AccessibilityInfo";
@@ -101,12 +100,12 @@ public class AccessibilityInfoModule extends ReactContextBaseJavaModule
     return value != null && value.equals("0.0");
   }
 
-  @ReactMethod
+  @Override
   public void isReduceMotionEnabled(Callback successCallback) {
     successCallback.invoke(mReduceMotionEnabled);
   }
 
-  @ReactMethod
+  @Override
   public void isTouchExplorationEnabled(Callback successCallback) {
     successCallback.invoke(mTouchExplorationEnabled);
   }
@@ -183,7 +182,7 @@ public class AccessibilityInfoModule extends ReactContextBaseJavaModule
   @Override
   public void onHostDestroy() {}
 
-  @ReactMethod
+  @Override
   public void announceForAccessibility(String message) {
     if (mAccessibilityManager == null || !mAccessibilityManager.isEnabled()) {
       return;
@@ -196,4 +195,9 @@ public class AccessibilityInfoModule extends ReactContextBaseJavaModule
 
     mAccessibilityManager.sendAccessibilityEvent(event);
   }
+
+  @Override
+  public void setAccessibilityFocus(double reactTag) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/appearance/AppearanceModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/appearance/AppearanceModule.java
index 861d64180bc..162f6bf87c4 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/appearance/AppearanceModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/appearance/AppearanceModule.java
@@ -9,17 +9,16 @@ package com.facebook.react.modules.appearance;
 
 import android.content.Context;
 import android.content.res.Configuration;
+import com.facebook.fbreact.specs.NativeAppearanceSpec;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.modules.core.DeviceEventManagerModule.RCTDeviceEventEmitter;
 
 /** Module that exposes the user's preferred color scheme. */
 @ReactModule(name = AppearanceModule.NAME)
-public class AppearanceModule extends ReactContextBaseJavaModule {
+public class AppearanceModule extends NativeAppearanceSpec {
 
   public static final String NAME = "Appearance";
 
@@ -51,18 +50,18 @@ public class AppearanceModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod(isBlockingSynchronousMethod = true)
+  @Override
   public String getColorScheme() {
     mColorScheme = colorSchemeForCurrentConfiguration(getReactApplicationContext());
     return mColorScheme;
   }
 
   /** Stub */
-  @ReactMethod
+  @Override
   public void addListener(String eventName) {}
 
   /** Stub */
-  @ReactMethod
+  @Override
   public void removeListeners(double count) {}
 
   /*
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/appstate/AppStateModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/appstate/AppStateModule.java
index 7b88dda632f..6cfa7841df0 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/appstate/AppStateModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/appstate/AppStateModule.java
@@ -7,12 +7,11 @@
 
 package com.facebook.react.modules.appstate;
 
+import com.facebook.fbreact.specs.NativeAppStateSpec;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.WindowFocusChangeListener;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.common.LifecycleState;
@@ -23,7 +22,7 @@ import java.util.Map;
 import javax.annotation.Nullable;
 
 @ReactModule(name = AppStateModule.NAME)
-public class AppStateModule extends ReactContextBaseJavaModule
+public class AppStateModule extends NativeAppStateSpec
     implements LifecycleEventListener, WindowFocusChangeListener {
   public static final String TAG = AppStateModule.class.getSimpleName();
 
@@ -52,13 +51,13 @@ public class AppStateModule extends ReactContextBaseJavaModule
   }
 
   @Override
-  public Map<String, Object> getConstants() {
+  public Map<String, Object> getTypedExportedConstants() {
     HashMap<String, Object> constants = new HashMap<>();
     constants.put(INITIAL_STATE, mAppState);
     return constants;
   }
 
-  @ReactMethod
+  @Override
   public void getCurrentAppState(Callback success, Callback error) {
     success.invoke(createAppStateEventMap());
   }
@@ -103,4 +102,14 @@ public class AppStateModule extends ReactContextBaseJavaModule
   private void sendAppStateChangeEvent() {
     sendEvent("appStateDidChange", createAppStateEventMap());
   }
+
+  @Override
+  public void addListener(String eventName) {
+    // iOS only
+  }
+
+  @Override
+  public void removeListeners(double count) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/blob/BlobModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/blob/BlobModule.java
index 12ce373ccab..fa782cf9770 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/blob/BlobModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/blob/BlobModule.java
@@ -13,11 +13,10 @@ import android.net.Uri;
 import android.provider.MediaStore;
 import android.webkit.MimeTypeMap;
 import androidx.annotation.Nullable;
+import com.facebook.fbreact.specs.NativeBlobModuleSpec;
 import com.facebook.proguard.annotations.DoNotStrip;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.WritableMap;
@@ -43,7 +42,7 @@ import okhttp3.ResponseBody;
 import okio.ByteString;
 
 @ReactModule(name = BlobModule.NAME)
-public class BlobModule extends ReactContextBaseJavaModule {
+public class BlobModule extends NativeBlobModuleSpec {
 
   public static final String NAME = "BlobModule";
 
@@ -156,7 +155,7 @@ public class BlobModule extends ReactContextBaseJavaModule {
   }
 
   @Override
-  public @Nullable Map<String, Object> getConstants() {
+  public @Nullable Map<String, Object> getTypedExportedConstants() {
     // The application can register BlobProvider as a ContentProvider so that blobs are resolvable.
     // If it does, it needs to tell us what authority was used via this string resource.
     Resources resources = getReactApplicationContext().getResources();
@@ -296,7 +295,7 @@ public class BlobModule extends ReactContextBaseJavaModule {
     return null;
   }
 
-  @ReactMethod
+  @Override
   public void addNetworkingHandler() {
     ReactApplicationContext reactApplicationContext = getReactApplicationContextIfActiveOrWarn();
 
@@ -309,8 +308,10 @@ public class BlobModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
-  public void addWebSocketHandler(final int id) {
+  @Override
+  public void addWebSocketHandler(final double idDouble) {
+    final int id = (int) idDouble;
+
     WebSocketModule webSocketModule = getWebSocketModule("addWebSocketHandler");
 
     if (webSocketModule != null) {
@@ -318,8 +319,10 @@ public class BlobModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
-  public void removeWebSocketHandler(final int id) {
+  @Override
+  public void removeWebSocketHandler(final double idDouble) {
+    final int id = (int) idDouble;
+
     WebSocketModule webSocketModule = getWebSocketModule("removeWebSocketHandler");
 
     if (webSocketModule != null) {
@@ -327,8 +330,10 @@ public class BlobModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
-  public void sendOverSocket(ReadableMap blob, int id) {
+  @Override
+  public void sendOverSocket(ReadableMap blob, double idDouble) {
+    int id = (int) idDouble;
+
     WebSocketModule webSocketModule = getWebSocketModule("sendOverSocket");
 
     if (webSocketModule != null) {
@@ -342,7 +347,7 @@ public class BlobModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void createFromParts(ReadableArray parts, String blobId) {
     int totalBlobSize = 0;
     ArrayList<byte[]> partList = new ArrayList<>(parts.size());
@@ -370,7 +375,7 @@ public class BlobModule extends ReactContextBaseJavaModule {
     store(buffer.array(), blobId);
   }
 
-  @ReactMethod
+  @Override
   public void release(String blobId) {
     remove(blobId);
   }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/blob/FileReaderModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/blob/FileReaderModule.java
index 1345a576bd6..805d744cf0e 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/blob/FileReaderModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/blob/FileReaderModule.java
@@ -8,15 +8,14 @@
 package com.facebook.react.modules.blob;
 
 import android.util.Base64;
+import com.facebook.fbreact.specs.NativeFileReaderModuleSpec;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.module.annotations.ReactModule;
 
 @ReactModule(name = FileReaderModule.NAME)
-public class FileReaderModule extends ReactContextBaseJavaModule {
+public class FileReaderModule extends NativeFileReaderModuleSpec {
 
   public static final String NAME = "FileReaderModule";
   private static final String ERROR_INVALID_BLOB = "ERROR_INVALID_BLOB";
@@ -40,7 +39,7 @@ public class FileReaderModule extends ReactContextBaseJavaModule {
     return null;
   }
 
-  @ReactMethod
+  @Override
   public void readAsText(ReadableMap blob, String encoding, Promise promise) {
     BlobModule blobModule = getBlobModule("readAsText");
 
@@ -65,7 +64,7 @@ public class FileReaderModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void readAsDataURL(ReadableMap blob, Promise promise) {
     BlobModule blobModule = getBlobModule("readAsDataURL");
 
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/camera/CameraRollManager.java b/ReactAndroid/src/main/java/com/facebook/react/modules/camera/CameraRollManager.java
index 4e5f1bd513f..05746f4f508 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/camera/CameraRollManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/camera/CameraRollManager.java
@@ -22,14 +22,13 @@ import android.provider.MediaStore.Images;
 import android.text.TextUtils;
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeCameraRollManagerSpec;
 import com.facebook.react.bridge.GuardedAsyncTask;
 import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.WritableArray;
@@ -56,7 +55,7 @@ import java.util.List;
  * {@link MediaStore.Images}).
  */
 @ReactModule(name = CameraRollManager.NAME)
-public class CameraRollManager extends ReactContextBaseJavaModule {
+public class CameraRollManager extends NativeCameraRollManagerSpec {
 
   public static final String NAME = "CameraRollManager";
 
@@ -102,7 +101,7 @@ public class CameraRollManager extends ReactContextBaseJavaModule {
    * @param uri the file://, http:// or https:// URI of the image to save
    * @param promise to be resolved or rejected
    */
-  @ReactMethod
+  @Override
   public void saveToCameraRoll(String uri, String type, Promise promise) {
     new SaveToCameraRoll(getReactApplicationContext(), Uri.parse(uri), promise)
         .executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
@@ -223,7 +222,7 @@ public class CameraRollManager extends ReactContextBaseJavaModule {
    * @param promise the Promise to be resolved when the photos are loaded; for a format of the
    *     parameters passed to this callback, see {@code getPhotosReturnChecker} in CameraRoll.js
    */
-  @ReactMethod
+  @Override
   public void getPhotos(final ReadableMap params, final Promise promise) {
     int first = params.getInt("first");
     String after = params.hasKey("after") ? params.getString("after") : null;
@@ -523,4 +522,9 @@ public class CameraRollManager extends ReactContextBaseJavaModule {
       node.putMap("location", location);
     }
   }
+
+  @Override
+  public void deletePhotos(ReadableArray assets, Promise promise) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageEditingManager.java b/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageEditingManager.java
index 9bc82530d34..e1ef2238ede 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageEditingManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageEditingManager.java
@@ -22,14 +22,13 @@ import android.provider.MediaStore;
 import android.text.TextUtils;
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeImageEditorSpec;
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.GuardedAsyncTask;
 import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.common.ReactConstants;
 import com.facebook.react.module.annotations.ReactModule;
@@ -46,7 +45,7 @@ import java.util.List;
 
 /** Native module that provides image cropping functionality. */
 @ReactModule(name = ImageEditingManager.NAME)
-public class ImageEditingManager extends ReactContextBaseJavaModule {
+public class ImageEditingManager extends NativeImageEditorSpec {
 
   public static final String NAME = "ImageEditingManager";
 
@@ -154,7 +153,7 @@ public class ImageEditingManager extends ReactContextBaseJavaModule {
    *     is passed to this callback is the file:// URI of the new image
    * @param error callback to be invoked when an error occurs (e.g. can't create file etc.)
    */
-  @ReactMethod
+  @Override
   public void cropImage(
       String uri, ReadableMap options, final Callback success, final Callback error) {
     ReadableMap offset = options.hasKey("offset") ? options.getMap("offset") : null;
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageStoreManager.java b/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageStoreManager.java
index 5133955d936..8bf377cfb4c 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageStoreManager.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/camera/ImageStoreManager.java
@@ -12,12 +12,11 @@ import android.net.Uri;
 import android.os.AsyncTask;
 import android.util.Base64;
 import android.util.Base64OutputStream;
+import com.facebook.fbreact.specs.NativeImageStoreSpec;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.GuardedAsyncTask;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.module.annotations.ReactModule;
 import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
@@ -26,7 +25,7 @@ import java.io.IOException;
 import java.io.InputStream;
 
 @ReactModule(name = ImageStoreManager.NAME)
-public class ImageStoreManager extends ReactContextBaseJavaModule {
+public class ImageStoreManager extends NativeImageStoreSpec {
 
   public static final String NAME = "ImageStoreManager";
   private static final int BUFFER_SIZE = 8192;
@@ -47,7 +46,7 @@ public class ImageStoreManager extends ReactContextBaseJavaModule {
    * @param success callback to be invoked with the base64 string as the only argument
    * @param error callback to be invoked on error (e.g. file not found, not readable etc.)
    */
-  @ReactMethod
+  @Override
   public void getBase64ForTag(String uri, Callback success, Callback error) {
     new GetBase64Task(getReactApplicationContext(), uri, success, error)
         .executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
@@ -106,4 +105,20 @@ public class ImageStoreManager extends ReactContextBaseJavaModule {
       // shhh
     }
   }
+
+  @Override
+  public void hasImageForTag(String uri, Callback callback) {
+    // iOS only
+  }
+
+  @Override
+  public void removeImageForTag(String uri) {
+    // iOS only
+  }
+
+  @Override
+  public void addImageFromBase64(
+      String base64ImageData, Callback successCallback, Callback errorCallback) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/core/DeviceEventManagerModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/core/DeviceEventManagerModule.java
index ec8e8c3e2c1..cf823171643 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/core/DeviceEventManagerModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/core/DeviceEventManagerModule.java
@@ -10,19 +10,18 @@ package com.facebook.react.modules.core;
 import android.net.Uri;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import com.facebook.fbreact.specs.NativeDeviceEventManagerSpec;
 import com.facebook.proguard.annotations.DoNotStrip;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.JavaScriptModule;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.module.annotations.ReactModule;
 
 /** Native module that handles device hardware events like hardware back presses. */
 @ReactModule(name = DeviceEventManagerModule.NAME)
-public class DeviceEventManagerModule extends ReactContextBaseJavaModule {
+public class DeviceEventManagerModule extends NativeDeviceEventManagerSpec {
   public static final String NAME = "DeviceEventManager";
 
   @DoNotStrip
@@ -71,7 +70,7 @@ public class DeviceEventManagerModule extends ReactContextBaseJavaModule {
    * Invokes the default back handler for the host of this catalyst instance. This should be invoked
    * if JS does not want to handle the back press itself.
    */
-  @ReactMethod
+  @Override
   public void invokeDefaultBackPressHandler() {
     // There should be no need to check if the catalyst instance is alive. After initialization
     // the thread instances cannot be null, and scheduling on a thread after ReactApplicationContext
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/core/ExceptionsManagerModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/core/ExceptionsManagerModule.java
index c2d7a38e00c..265ecf88be0 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/core/ExceptionsManagerModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/core/ExceptionsManagerModule.java
@@ -8,10 +8,9 @@
 package com.facebook.react.modules.core;
 
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeExceptionsManagerSpec;
 import com.facebook.react.bridge.Arguments;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
 import com.facebook.react.bridge.JavaOnlyMap;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.common.JavascriptException;
@@ -22,13 +21,14 @@ import com.facebook.react.util.ExceptionDataHelper;
 import com.facebook.react.util.JSStackTrace;
 
 @ReactModule(name = ExceptionsManagerModule.NAME)
-public class ExceptionsManagerModule extends ReactContextBaseJavaModule {
+public class ExceptionsManagerModule extends NativeExceptionsManagerSpec {
 
   public static final String NAME = "ExceptionsManager";
 
   private final DevSupportManager mDevSupportManager;
 
   public ExceptionsManagerModule(DevSupportManager devSupportManager) {
+    super(null);
     mDevSupportManager = devSupportManager;
   }
 
@@ -37,8 +37,10 @@ public class ExceptionsManagerModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod
-  public void reportFatalException(String message, ReadableArray stack, int id) {
+  @Override
+  public void reportFatalException(String message, ReadableArray stack, double idDouble) {
+    int id = (int) idDouble;
+
     JavaOnlyMap data = new JavaOnlyMap();
     data.putString("message", message);
     data.putArray("stack", stack);
@@ -47,8 +49,10 @@ public class ExceptionsManagerModule extends ReactContextBaseJavaModule {
     reportException(data);
   }
 
-  @ReactMethod
-  public void reportSoftException(String message, ReadableArray stack, int id) {
+  @Override
+  public void reportSoftException(String message, ReadableArray stack, double idDouble) {
+    int id = (int) idDouble;
+
     JavaOnlyMap data = new JavaOnlyMap();
     data.putString("message", message);
     data.putArray("stack", stack);
@@ -57,7 +61,7 @@ public class ExceptionsManagerModule extends ReactContextBaseJavaModule {
     reportException(data);
   }
 
-  @ReactMethod
+  @Override
   public void reportException(ReadableMap data) {
     String message = data.hasKey("message") ? data.getString("message") : "";
     ReadableArray stack = data.hasKey("stack") ? data.getArray("stack") : Arguments.createArray();
@@ -87,14 +91,17 @@ public class ExceptionsManagerModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
-  public void updateExceptionMessage(String title, ReadableArray details, int exceptionId) {
+  @Override
+  public void updateExceptionMessage(
+      String title, ReadableArray details, double exceptionIdDouble) {
+    int exceptionId = (int) exceptionIdDouble;
+
     if (mDevSupportManager.getDevSupportEnabled()) {
       mDevSupportManager.updateJSError(title, details, exceptionId);
     }
   }
 
-  @ReactMethod
+  @Override
   public void dismissRedbox() {
     if (mDevSupportManager.getDevSupportEnabled()) {
       mDevSupportManager.hideRedboxDialog();
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/core/HeadlessJsTaskSupportModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/core/HeadlessJsTaskSupportModule.java
index b4459e90f0e..ce9f6fc48c7 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/core/HeadlessJsTaskSupportModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/core/HeadlessJsTaskSupportModule.java
@@ -8,10 +8,9 @@
 package com.facebook.react.modules.core;
 
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeHeadlessJsTaskSupportSpec;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.jstasks.HeadlessJsTaskContext;
 import com.facebook.react.module.annotations.ReactModule;
 
@@ -20,7 +19,7 @@ import com.facebook.react.module.annotations.ReactModule;
  * it can e.g. release any resources, stop timers etc.
  */
 @ReactModule(name = HeadlessJsTaskSupportModule.NAME)
-public class HeadlessJsTaskSupportModule extends ReactContextBaseJavaModule {
+public class HeadlessJsTaskSupportModule extends NativeHeadlessJsTaskSupportSpec {
 
   public static final String NAME = "HeadlessJsTaskSupport";
 
@@ -33,8 +32,10 @@ public class HeadlessJsTaskSupportModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod
-  public void notifyTaskRetry(int taskId, Promise promise) {
+  @Override
+  public void notifyTaskRetry(double taskIdDouble, Promise promise) {
+    int taskId = (int) taskIdDouble;
+
     HeadlessJsTaskContext headlessJsTaskContext =
         HeadlessJsTaskContext.getInstance(getReactApplicationContext());
     if (headlessJsTaskContext.isTaskRunning(taskId)) {
@@ -49,8 +50,10 @@ public class HeadlessJsTaskSupportModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
-  public void notifyTaskFinished(int taskId) {
+  @Override
+  public void notifyTaskFinished(double taskIdDouble) {
+    int taskId = (int) taskIdDouble;
+
     HeadlessJsTaskContext headlessJsTaskContext =
         HeadlessJsTaskContext.getInstance(getReactApplicationContext());
     if (headlessJsTaskContext.isTaskRunning(taskId)) {
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/core/TimingModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/core/TimingModule.java
index b7e7d052480..dbbbf843b38 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/core/TimingModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/core/TimingModule.java
@@ -7,10 +7,9 @@
 
 package com.facebook.react.modules.core;
 
+import com.facebook.fbreact.specs.NativeTimingSpec;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.devsupport.interfaces.DevSupportManager;
 import com.facebook.react.jstasks.HeadlessJsTaskContext;
@@ -19,7 +18,7 @@ import com.facebook.react.module.annotations.ReactModule;
 
 /** Native module for JS timer execution. Timers fire on frame boundaries. */
 @ReactModule(name = TimingModule.NAME)
-public final class TimingModule extends ReactContextBaseJavaModule
+public final class TimingModule extends NativeTimingSpec
     implements LifecycleEventListener, HeadlessJsTaskEventListener {
 
   public class BridgeTimerManager implements JavaScriptTimerManager {
@@ -79,21 +78,26 @@ public final class TimingModule extends ReactContextBaseJavaModule
     return NAME;
   }
 
-  @ReactMethod
+  @Override
   public void createTimer(
-      final int callbackID,
-      final int duration,
+      final double callbackIDDouble,
+      final double durationDouble,
       final double jsSchedulingTime,
       final boolean repeat) {
+    final int callbackID = (int) callbackIDDouble;
+    final int duration = (int) durationDouble;
+
     mJavaTimerManager.createAndMaybeCallTimer(callbackID, duration, jsSchedulingTime, repeat);
   }
 
-  @ReactMethod
-  public void deleteTimer(int timerId) {
+  @Override
+  public void deleteTimer(double timerIdDouble) {
+    int timerId = (int) timerIdDouble;
+
     mJavaTimerManager.deleteTimer(timerId);
   }
 
-  @ReactMethod
+  @Override
   public void setSendIdleEvents(final boolean sendIdleEvents) {
     mJavaTimerManager.setSendIdleEvents(sendIdleEvents);
   }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/datepicker/DatePickerDialogModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/datepicker/DatePickerDialogModule.java
index d44c4f8b9be..20cb8258938 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/datepicker/DatePickerDialogModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/datepicker/DatePickerDialogModule.java
@@ -18,6 +18,7 @@ import androidx.annotation.Nullable;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.FragmentActivity;
 import androidx.fragment.app.FragmentManager;
+import com.facebook.fbreact.specs.NativeDatePickerAndroidSpec;
 import com.facebook.react.bridge.*;
 import com.facebook.react.common.annotations.VisibleForTesting;
 import com.facebook.react.module.annotations.ReactModule;
@@ -27,7 +28,7 @@ import com.facebook.react.module.annotations.ReactModule;
  * the user selects a date.
  */
 @ReactModule(name = DatePickerDialogModule.FRAGMENT_TAG)
-public class DatePickerDialogModule extends ReactContextBaseJavaModule {
+public class DatePickerDialogModule extends NativeDatePickerAndroidSpec {
 
   @VisibleForTesting public static final String FRAGMENT_TAG = "DatePickerAndroid";
 
@@ -45,7 +46,6 @@ public class DatePickerDialogModule extends ReactContextBaseJavaModule {
     super(reactContext);
   }
 
-  @Override
   public @NonNull String getName() {
     return DatePickerDialogModule.FRAGMENT_TAG;
   }
@@ -100,7 +100,7 @@ public class DatePickerDialogModule extends ReactContextBaseJavaModule {
    *     action is {@code dateSetAction} or {@code dismissedAction}, depending on what the user did.
    *     If the action is dismiss, year, month and date are undefined.
    */
-  @ReactMethod
+  @Override
   public void open(@Nullable final ReadableMap options, Promise promise) {
     Activity raw_activity = getCurrentActivity();
     if (raw_activity == null || !(raw_activity instanceof FragmentActivity)) {
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/debug/AnimationsDebugModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/debug/AnimationsDebugModule.java
index 8e0e98a5c21..da69cf93c05 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/debug/AnimationsDebugModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/debug/AnimationsDebugModule.java
@@ -10,10 +10,9 @@ package com.facebook.react.modules.debug;
 import android.widget.Toast;
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeAnimationsDebugModuleSpec;
 import com.facebook.react.bridge.JSApplicationCausedNativeException;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.common.ReactConstants;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.modules.debug.interfaces.DeveloperSettings;
@@ -24,7 +23,7 @@ import java.util.Locale;
  * going from one screen to another).
  */
 @ReactModule(name = AnimationsDebugModule.NAME)
-public class AnimationsDebugModule extends ReactContextBaseJavaModule {
+public class AnimationsDebugModule extends NativeAnimationsDebugModuleSpec {
 
   protected static final String NAME = "AnimationsDebugModule";
 
@@ -42,7 +41,7 @@ public class AnimationsDebugModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod
+  @Override
   public void startRecordingFps() {
     if (mCatalystSettings == null || !mCatalystSettings.isAnimationFpsDebugEnabled()) {
       return;
@@ -61,7 +60,7 @@ public class AnimationsDebugModule extends ReactContextBaseJavaModule {
    * (unix time) so that we know when the animation stopped from the JS perspective and we don't
    * count time after as being part of the animation.
    */
-  @ReactMethod
+  @Override
   public void stopRecordingFps(double animationStopTimeMs) {
     if (mFrameCallback == null) {
       return;
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/debug/DevSettingsModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/debug/DevSettingsModule.java
index 55ad479ebc7..0a970ca3f7b 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/debug/DevSettingsModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/debug/DevSettingsModule.java
@@ -7,10 +7,9 @@
 
 package com.facebook.react.modules.debug;
 
+import com.facebook.fbreact.specs.NativeDevSettingsSpec;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.devsupport.interfaces.DevOptionHandler;
@@ -22,7 +21,7 @@ import com.facebook.react.modules.core.DeviceEventManagerModule.RCTDeviceEventEm
  * Module that exposes the URL to the source code map (used for exception stack trace parsing) to JS
  */
 @ReactModule(name = DevSettingsModule.NAME)
-public class DevSettingsModule extends ReactContextBaseJavaModule {
+public class DevSettingsModule extends NativeDevSettingsSpec {
 
   public static final String NAME = "DevSettings";
 
@@ -40,7 +39,7 @@ public class DevSettingsModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod
+  @Override
   public void reload() {
     if (mDevSupportManager.getDevSupportEnabled()) {
       UiThreadUtil.runOnUiThread(
@@ -53,37 +52,37 @@ public class DevSettingsModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void reloadWithReason(String reason) {
     this.reload();
   }
 
-  @ReactMethod
+  @Override
   public void onFastRefresh() {
     // noop
   }
 
-  @ReactMethod
+  @Override
   public void setHotLoadingEnabled(boolean isHotLoadingEnabled) {
     mDevSupportManager.setHotModuleReplacementEnabled(isHotLoadingEnabled);
   }
 
-  @ReactMethod
+  @Override
   public void setIsDebuggingRemotely(boolean isDebugginRemotelyEnabled) {
     mDevSupportManager.setRemoteJSDebugEnabled(isDebugginRemotelyEnabled);
   }
 
-  @ReactMethod
+  @Override
   public void setProfilingEnabled(boolean isProfilingEnabled) {
     mDevSupportManager.setFpsDebugEnabled(isProfilingEnabled);
   }
 
-  @ReactMethod
+  @Override
   public void toggleElementInspector() {
     mDevSupportManager.toggleElementInspector();
   }
 
-  @ReactMethod
+  @Override
   public void addMenuItem(final String title) {
     mDevSupportManager.addCustomDevOption(
         title,
@@ -104,4 +103,9 @@ public class DevSettingsModule extends ReactContextBaseJavaModule {
           }
         });
   }
+
+  @Override
+  public void setIsShakeToShowDevMenuEnabled(boolean enabled) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/dialog/DialogModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/dialog/DialogModule.java
index 437336f0ab0..e3a25072156 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/dialog/DialogModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/dialog/DialogModule.java
@@ -17,11 +17,10 @@ import androidx.annotation.Nullable;
 import androidx.fragment.app.FragmentActivity;
 import androidx.fragment.app.FragmentManager;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeDialogManagerAndroidSpec;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.SoftAssertions;
@@ -31,7 +30,7 @@ import com.facebook.react.module.annotations.ReactModule;
 import java.util.Map;
 
 @ReactModule(name = DialogModule.NAME)
-public class DialogModule extends ReactContextBaseJavaModule implements LifecycleEventListener {
+public class DialogModule extends NativeDialogManagerAndroidSpec implements LifecycleEventListener {
 
   /* package */ static final String FRAGMENT_TAG =
       "com.facebook.catalyst.react.dialog.DialogModule";
@@ -149,7 +148,7 @@ public class DialogModule extends ReactContextBaseJavaModule implements Lifecycl
   }
 
   @Override
-  public Map<String, Object> getConstants() {
+  public Map<String, Object> getTypedExportedConstants() {
     return CONSTANTS;
   }
 
@@ -179,7 +178,7 @@ public class DialogModule extends ReactContextBaseJavaModule implements Lifecycl
     }
   }
 
-  @ReactMethod
+  @Override
   public void showAlert(
       ReadableMap options, Callback errorCallback, final Callback actionCallback) {
     final FragmentManagerHelper fragmentManagerHelper = getFragmentManagerHelper();
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/intent/IntentModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/intent/IntentModule.java
index f08290f8e73..7c324332e37 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/intent/IntentModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/intent/IntentModule.java
@@ -15,11 +15,10 @@ import android.net.Uri;
 import android.nfc.NfcAdapter;
 import android.provider.Settings;
 import androidx.annotation.Nullable;
+import com.facebook.fbreact.specs.NativeLinkingSpec;
 import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.ReadableType;
@@ -27,7 +26,7 @@ import com.facebook.react.module.annotations.ReactModule;
 
 /** Intent module. Launch other activities or open URLs. */
 @ReactModule(name = IntentModule.NAME)
-public class IntentModule extends ReactContextBaseJavaModule {
+public class IntentModule extends NativeLinkingSpec {
 
   public static final String NAME = "IntentAndroid";
 
@@ -45,7 +44,7 @@ public class IntentModule extends ReactContextBaseJavaModule {
    *
    * @param promise a promise which is resolved with the initial URL
    */
-  @ReactMethod
+  @Override
   public void getInitialURL(Promise promise) {
     try {
       Activity currentActivity = getCurrentActivity();
@@ -79,7 +78,7 @@ public class IntentModule extends ReactContextBaseJavaModule {
    *
    * @param url the URL to open
    */
-  @ReactMethod
+  @Override
   public void openURL(String url, Promise promise) {
     if (url == null || url.isEmpty()) {
       promise.reject(new JSApplicationIllegalArgumentException("Invalid URL: " + url));
@@ -121,7 +120,7 @@ public class IntentModule extends ReactContextBaseJavaModule {
    * @param url the URL to open
    * @param promise a promise that is always resolved with a boolean argument
    */
-  @ReactMethod
+  @Override
   public void canOpenURL(String url, Promise promise) {
     if (url == null || url.isEmpty()) {
       promise.reject(new JSApplicationIllegalArgumentException("Invalid URL: " + url));
@@ -148,7 +147,7 @@ public class IntentModule extends ReactContextBaseJavaModule {
    *
    * @param promise a promise which is resolved when the Settings is opened
    */
-  @ReactMethod
+  @Override
   public void openSettings(Promise promise) {
     try {
       Intent intent = new Intent();
@@ -182,7 +181,7 @@ public class IntentModule extends ReactContextBaseJavaModule {
    * @param action The general action to be performed
    * @param extras An array of extras [{ String, String | Number | Boolean }]
    */
-  @ReactMethod
+  @Override
   public void sendIntent(String action, @Nullable ReadableArray extras, Promise promise) {
     if (action == null || action.isEmpty()) {
       promise.reject(new JSApplicationIllegalArgumentException("Invalid Action: " + action + "."));
@@ -238,4 +237,14 @@ public class IntentModule extends ReactContextBaseJavaModule {
 
     getReactApplicationContext().startActivity(intent);
   }
+
+  @Override
+  public void addListener(String eventName) {
+    // iOS only
+  }
+
+  @Override
+  public void removeListeners(double count) {
+    // iOS only
+  }
 }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/permissions/PermissionsModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/permissions/PermissionsModule.java
index 15e93193b6f..879481740de 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/permissions/PermissionsModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/permissions/PermissionsModule.java
@@ -13,11 +13,10 @@ import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Process;
 import android.util.SparseArray;
+import com.facebook.fbreact.specs.NativePermissionsAndroidSpec;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.bridge.WritableNativeMap;
@@ -28,7 +27,7 @@ import java.util.ArrayList;
 
 /** Module that exposes the Android M Permission system to JS. */
 @ReactModule(name = PermissionsModule.NAME)
-public class PermissionsModule extends ReactContextBaseJavaModule implements PermissionListener {
+public class PermissionsModule extends NativePermissionsAndroidSpec implements PermissionListener {
 
   private static final String ERROR_INVALID_ACTIVITY = "E_INVALID_ACTIVITY";
   public static final String NAME = "PermissionsAndroid";
@@ -52,7 +51,7 @@ public class PermissionsModule extends ReactContextBaseJavaModule implements Per
    * Check if the app has the permission given. successCallback is called with true if the
    * permission had been granted, false otherwise. See {@link Activity#checkSelfPermission}.
    */
-  @ReactMethod
+  @Override
   public void checkPermission(final String permission, final Promise promise) {
     Context context = getReactApplicationContext().getBaseContext();
     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
@@ -72,7 +71,7 @@ public class PermissionsModule extends ReactContextBaseJavaModule implements Per
    * again). For devices before Android M, this always returns false. See {@link
    * Activity#shouldShowRequestPermissionRationale}.
    */
-  @ReactMethod
+  @Override
   public void shouldShowRequestPermissionRationale(final String permission, final Promise promise) {
     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
       promise.resolve(false);
@@ -92,7 +91,7 @@ public class PermissionsModule extends ReactContextBaseJavaModule implements Per
    * user has the permission given or not and resolves with GRANTED or DENIED. See {@link
    * Activity#checkSelfPermission}.
    */
-  @ReactMethod
+  @Override
   public void requestPermission(final String permission, final Promise promise) {
     Context context = getReactApplicationContext().getBaseContext();
     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
@@ -137,7 +136,7 @@ public class PermissionsModule extends ReactContextBaseJavaModule implements Per
     }
   }
 
-  @ReactMethod
+  @Override
   public void requestMultiplePermissions(final ReadableArray permissions, final Promise promise) {
     final WritableMap grantedPermissions = new WritableNativeMap();
     final ArrayList<String> permissionsToCheck = new ArrayList<String>();
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/share/ShareModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/share/ShareModule.java
index 024c7eb37a7..ee826d69eb9 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/share/ShareModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/share/ShareModule.java
@@ -9,18 +9,17 @@ package com.facebook.react.modules.share;
 
 import android.app.Activity;
 import android.content.Intent;
+import com.facebook.fbreact.specs.NativeShareModuleSpec;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.module.annotations.ReactModule;
 
 /** Intent module. Launch other activities or open URLs. */
 @ReactModule(name = ShareModule.NAME)
-public class ShareModule extends ReactContextBaseJavaModule {
+public class ShareModule extends NativeShareModuleSpec {
 
   public static final String NAME = "ShareModule";
   /* package */ static final String ACTION_SHARED = "sharedAction";
@@ -44,7 +43,7 @@ public class ShareModule extends ReactContextBaseJavaModule {
    * @param content the data to send
    * @param dialogTitle the title of the chooser dialog
    */
-  @ReactMethod
+  @Override
   public void share(ReadableMap content, String dialogTitle, Promise promise) {
     if (content == null) {
       promise.reject(ERROR_INVALID_CONTENT, "Content cannot be null");
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/sound/SoundManagerModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/sound/SoundManagerModule.java
index 215b76998a0..8e1b122defb 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/sound/SoundManagerModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/sound/SoundManagerModule.java
@@ -9,15 +9,14 @@ package com.facebook.react.modules.sound;
 
 import android.content.Context;
 import android.media.AudioManager;
+import com.facebook.fbreact.specs.NativeSoundManagerSpec;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.module.annotations.ReactModule;
 
 /** {@link NativeModule} that allows Playing device sounds from JS. */
 @ReactModule(name = SoundManagerModule.NAME)
-public class SoundManagerModule extends ReactContextBaseJavaModule {
+public class SoundManagerModule extends NativeSoundManagerSpec {
 
   public static final String NAME = "SoundManager";
 
@@ -30,7 +29,7 @@ public class SoundManagerModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod
+  @Override
   public void playTouchSound() {
     AudioManager audioManager =
         (AudioManager) getReactApplicationContext().getSystemService(Context.AUDIO_SERVICE);
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/statusbar/StatusBarModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/statusbar/StatusBarModule.java
index 3b23b4f0bff..1898a62a127 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/statusbar/StatusBarModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/statusbar/StatusBarModule.java
@@ -19,11 +19,10 @@ import android.view.WindowManager;
 import androidx.annotation.Nullable;
 import androidx.core.view.ViewCompat;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeStatusBarManagerAndroidSpec;
 import com.facebook.react.bridge.GuardedRunnable;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.common.MapBuilder;
 import com.facebook.react.common.ReactConstants;
@@ -33,7 +32,7 @@ import java.util.Map;
 
 /** {@link NativeModule} that allows changing the appearance of the status bar. */
 @ReactModule(name = StatusBarModule.NAME)
-public class StatusBarModule extends ReactContextBaseJavaModule {
+public class StatusBarModule extends NativeStatusBarManagerAndroidSpec {
 
   private static final String HEIGHT_KEY = "HEIGHT";
   private static final String DEFAULT_BACKGROUND_COLOR_KEY = "DEFAULT_BACKGROUND_COLOR";
@@ -49,7 +48,7 @@ public class StatusBarModule extends ReactContextBaseJavaModule {
   }
 
   @Override
-  public @Nullable Map<String, Object> getConstants() {
+  public @Nullable Map<String, Object> getTypedExportedConstants() {
     final Context context = getReactApplicationContext();
     final Activity activity = getCurrentActivity();
 
@@ -70,8 +69,10 @@ public class StatusBarModule extends ReactContextBaseJavaModule {
         HEIGHT_KEY, height, DEFAULT_BACKGROUND_COLOR_KEY, statusBarColorString);
   }
 
-  @ReactMethod
-  public void setColor(final int color, final boolean animated) {
+  @Override
+  public void setColor(final double colorDouble, final boolean animated) {
+    final int color = (int) colorDouble;
+
     final Activity activity = getCurrentActivity();
     if (activity == null) {
       FLog.w(
@@ -114,7 +115,7 @@ public class StatusBarModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void setTranslucent(final boolean translucent) {
     final Activity activity = getCurrentActivity();
     if (activity == null) {
@@ -156,7 +157,7 @@ public class StatusBarModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void setHidden(final boolean hidden) {
     final Activity activity = getCurrentActivity();
     if (activity == null) {
@@ -180,7 +181,7 @@ public class StatusBarModule extends ReactContextBaseJavaModule {
         });
   }
 
-  @ReactMethod
+  @Override
   public void setStyle(@Nullable final String style) {
     final Activity activity = getCurrentActivity();
     if (activity == null) {
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/storage/AsyncStorageModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/storage/AsyncStorageModule.java
index 368c2b5ec9c..2b605a571f9 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/storage/AsyncStorageModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/storage/AsyncStorageModule.java
@@ -15,12 +15,11 @@ import android.database.Cursor;
 import android.database.sqlite.SQLiteStatement;
 import android.os.AsyncTask;
 import com.facebook.common.logging.FLog;
+import com.facebook.fbreact.specs.NativeAsyncStorageSpec;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.GuardedAsyncTask;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.WritableArray;
 import com.facebook.react.bridge.WritableMap;
@@ -33,7 +32,7 @@ import java.util.HashSet;
 import java.util.concurrent.Executor;
 
 @ReactModule(name = AsyncStorageModule.NAME)
-public final class AsyncStorageModule extends ReactContextBaseJavaModule
+public final class AsyncStorageModule extends NativeAsyncStorageSpec
     implements ModuleDataCleaner.Cleanable {
 
   public static final String NAME = "AsyncSQLiteDBStorage";
@@ -120,7 +119,7 @@ public final class AsyncStorageModule extends ReactContextBaseJavaModule
    * Given an array of keys, this returns a map of (key, value) pairs for the keys found, and (key,
    * null) for the keys that haven't been found.
    */
-  @ReactMethod
+  @Override
   public void multiGet(final ReadableArray keys, final Callback callback) {
     if (keys == null) {
       callback.invoke(AsyncStorageErrorUtil.getInvalidKeyError(null), null);
@@ -196,7 +195,7 @@ public final class AsyncStorageModule extends ReactContextBaseJavaModule
    * return AsyncLocalStorageFailure, but all other pairs will have been inserted. The insertion
    * will replace conflicting (key, value) pairs.
    */
-  @ReactMethod
+  @Override
   public void multiSet(final ReadableArray keyValueArray, final Callback callback) {
     if (keyValueArray.size() == 0) {
       callback.invoke(AsyncStorageErrorUtil.getInvalidKeyError(null));
@@ -259,7 +258,7 @@ public final class AsyncStorageModule extends ReactContextBaseJavaModule
   }
 
   /** Removes all rows of the keys given. */
-  @ReactMethod
+  @Override
   public void multiRemove(final ReadableArray keys, final Callback callback) {
     if (keys.size() == 0) {
       callback.invoke(AsyncStorageErrorUtil.getInvalidKeyError(null));
@@ -313,7 +312,7 @@ public final class AsyncStorageModule extends ReactContextBaseJavaModule
    * Given an array of (key, value) pairs, this will merge the given values with the stored values
    * of the given keys, if they exist.
    */
-  @ReactMethod
+  @Override
   public void multiMerge(final ReadableArray keyValueArray, final Callback callback) {
     new GuardedAsyncTask<Void, Void>(getReactApplicationContext()) {
       @Override
@@ -373,7 +372,7 @@ public final class AsyncStorageModule extends ReactContextBaseJavaModule
   }
 
   /** Clears the database. */
-  @ReactMethod
+  @Override
   public void clear(final Callback callback) {
     new GuardedAsyncTask<Void, Void>(getReactApplicationContext()) {
       @Override
@@ -394,7 +393,7 @@ public final class AsyncStorageModule extends ReactContextBaseJavaModule
   }
 
   /** Returns an array with all keys from the database. */
-  @ReactMethod
+  @Override
   public void getAllKeys(final Callback callback) {
     new GuardedAsyncTask<Void, Void>(getReactApplicationContext()) {
       @Override
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/systeminfo/AndroidInfoModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/systeminfo/AndroidInfoModule.java
index 3eb747a869f..335cb2062f6 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/systeminfo/AndroidInfoModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/systeminfo/AndroidInfoModule.java
@@ -16,10 +16,9 @@ import android.content.res.Resources;
 import android.os.Build;
 import android.provider.Settings.Secure;
 import androidx.annotation.Nullable;
+import com.facebook.fbreact.specs.NativePlatformConstantsAndroidSpec;
 import com.facebook.react.R;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.common.build.ReactBuildConfig;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.turbomodule.core.interfaces.TurboModule;
@@ -29,7 +28,7 @@ import java.util.Map;
 /** Module that exposes Android Constants to JS. */
 @ReactModule(name = AndroidInfoModule.NAME)
 @SuppressLint("HardwareIds")
-public class AndroidInfoModule extends ReactContextBaseJavaModule implements TurboModule {
+public class AndroidInfoModule extends NativePlatformConstantsAndroidSpec implements TurboModule {
   public static final String NAME = "PlatformConstants";
   private static final String IS_TESTING = "IS_TESTING";
 
@@ -66,7 +65,7 @@ public class AndroidInfoModule extends ReactContextBaseJavaModule implements Tur
   }
 
   @Override
-  public @Nullable Map<String, Object> getConstants() {
+  public @Nullable Map<String, Object> getTypedExportedConstants() {
     HashMap<String, Object> constants = new HashMap<>();
     constants.put("Version", Build.VERSION.SDK_INT);
     constants.put("Release", Build.VERSION.RELEASE);
@@ -83,7 +82,7 @@ public class AndroidInfoModule extends ReactContextBaseJavaModule implements Tur
     return constants;
   }
 
-  @ReactMethod(isBlockingSynchronousMethod = true)
+  @Override
   public String getAndroidID() {
     return Secure.getString(getReactApplicationContext().getContentResolver(), Secure.ANDROID_ID);
   }
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/timepicker/TimePickerDialogModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/timepicker/TimePickerDialogModule.java
index 412cf5d369a..b40f7b6b46c 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/timepicker/TimePickerDialogModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/timepicker/TimePickerDialogModule.java
@@ -17,11 +17,10 @@ import androidx.annotation.Nullable;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.FragmentActivity;
 import androidx.fragment.app.FragmentManager;
+import com.facebook.fbreact.specs.NativeTimePickerAndroidSpec;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.bridge.WritableNativeMap;
@@ -33,7 +32,7 @@ import com.facebook.react.module.annotations.ReactModule;
  * the user selects a time.
  */
 @ReactModule(name = TimePickerDialogModule.FRAGMENT_TAG)
-public class TimePickerDialogModule extends ReactContextBaseJavaModule {
+public class TimePickerDialogModule extends NativeTimePickerAndroidSpec {
 
   @VisibleForTesting public static final String FRAGMENT_TAG = "TimePickerAndroid";
 
@@ -87,14 +86,14 @@ public class TimePickerDialogModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void open(@Nullable final ReadableMap options, Promise promise) {
 
     Activity raw_activity = getCurrentActivity();
     if (raw_activity == null || !(raw_activity instanceof FragmentActivity)) {
       promise.reject(
-        ERROR_NO_ACTIVITY,
-        "Tried to open a DatePicker dialog while not attached to a FragmentActivity");
+          ERROR_NO_ACTIVITY,
+          "Tried to open a DatePicker dialog while not attached to a FragmentActivity");
       return;
     }
 
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/toast/ToastModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/toast/ToastModule.java
index a7746375af3..c646c946327 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/toast/ToastModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/toast/ToastModule.java
@@ -9,10 +9,9 @@ package com.facebook.react.modules.toast;
 
 import android.view.Gravity;
 import android.widget.Toast;
+import com.facebook.fbreact.specs.NativeToastAndroidSpec;
 import com.facebook.react.bridge.NativeModule;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.common.MapBuilder;
 import com.facebook.react.module.annotations.ReactModule;
@@ -20,7 +19,7 @@ import java.util.Map;
 
 /** {@link NativeModule} that allows JS to show an Android Toast. */
 @ReactModule(name = ToastModule.NAME)
-public class ToastModule extends ReactContextBaseJavaModule {
+public class ToastModule extends NativeToastAndroidSpec {
 
   private static final String DURATION_SHORT_KEY = "SHORT";
   private static final String DURATION_LONG_KEY = "LONG";
@@ -40,7 +39,7 @@ public class ToastModule extends ReactContextBaseJavaModule {
   }
 
   @Override
-  public Map<String, Object> getConstants() {
+  public Map<String, Object> getTypedExportedConstants() {
     final Map<String, Object> constants = MapBuilder.newHashMap();
     constants.put(DURATION_SHORT_KEY, Toast.LENGTH_SHORT);
     constants.put(DURATION_LONG_KEY, Toast.LENGTH_LONG);
@@ -50,8 +49,10 @@ public class ToastModule extends ReactContextBaseJavaModule {
     return constants;
   }
 
-  @ReactMethod
-  public void show(final String message, final int duration) {
+  @Override
+  public void show(final String message, final double durationDouble) {
+    final int duration = (int) durationDouble;
+
     UiThreadUtil.runOnUiThread(
         new Runnable() {
           @Override
@@ -61,8 +62,12 @@ public class ToastModule extends ReactContextBaseJavaModule {
         });
   }
 
-  @ReactMethod
-  public void showWithGravity(final String message, final int duration, final int gravity) {
+  @Override
+  public void showWithGravity(
+      final String message, final double durationDouble, final double gravityDouble) {
+    final int duration = (int) durationDouble;
+    final int gravity = (int) gravityDouble;
+
     UiThreadUtil.runOnUiThread(
         new Runnable() {
           @Override
@@ -74,13 +79,18 @@ public class ToastModule extends ReactContextBaseJavaModule {
         });
   }
 
-  @ReactMethod
+  @Override
   public void showWithGravityAndOffset(
       final String message,
-      final int duration,
-      final int gravity,
-      final int xOffset,
-      final int yOffset) {
+      final double durationDouble,
+      final double gravityDouble,
+      final double xOffsetDouble,
+      final double yOffsetDouble) {
+    final int duration = (int) durationDouble;
+    final int gravity = (int) gravityDouble;
+    final int xOffset = (int) xOffsetDouble;
+    final int yOffset = (int) yOffsetDouble;
+
     UiThreadUtil.runOnUiThread(
         new Runnable() {
           @Override
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/vibration/VibrationModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/vibration/VibrationModule.java
index 5f8eb0c1ed8..5e594ba9bd4 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/vibration/VibrationModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/vibration/VibrationModule.java
@@ -10,15 +10,14 @@ package com.facebook.react.modules.vibration;
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.os.Vibrator;
+import com.facebook.fbreact.specs.NativeVibrationSpec;
 import com.facebook.react.bridge.ReactApplicationContext;
-import com.facebook.react.bridge.ReactContextBaseJavaModule;
-import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.module.annotations.ReactModule;
 
 @SuppressLint("MissingPermission")
 @ReactModule(name = VibrationModule.NAME)
-public class VibrationModule extends ReactContextBaseJavaModule {
+public class VibrationModule extends NativeVibrationSpec {
 
   public static final String NAME = "Vibration";
 
@@ -31,16 +30,20 @@ public class VibrationModule extends ReactContextBaseJavaModule {
     return NAME;
   }
 
-  @ReactMethod
-  public void vibrate(int duration) {
+  @Override
+  public void vibrate(Double durationDouble) {
+    int duration = (int) durationDouble.doubleValue();
+
     Vibrator v = (Vibrator) getReactApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
     if (v != null) {
       v.vibrate(duration);
     }
   }
 
-  @ReactMethod
-  public void vibrateByPattern(ReadableArray pattern, int repeat) {
+  @Override
+  public void vibrateByPattern(ReadableArray pattern, double repeatDouble) {
+    int repeat = (int) repeatDouble;
+
     Vibrator v = (Vibrator) getReactApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
     if (v != null) {
       long[] patternLong = new long[pattern.size()];
@@ -51,7 +54,7 @@ public class VibrationModule extends ReactContextBaseJavaModule {
     }
   }
 
-  @ReactMethod
+  @Override
   public void cancel() {
     Vibrator v = (Vibrator) getReactApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
     if (v != null) {