diff --git a/native/android/app/src/cpp/CommMMKV.cpp b/native/android/app/src/cpp/CommMMKV.cpp
--- a/native/android/app/src/cpp/CommMMKV.cpp
+++ b/native/android/app/src/cpp/CommMMKV.cpp
@@ -96,6 +96,32 @@
     }
     method(cls, keysJava);
   }
+
+  static void addElementToStringSet(std::string setKey, std::string element) {
+    static const auto cls = javaClassStatic();
+    static auto method = cls->getStaticMethod<void(std::string, std::string)>(
+        "addElementToStringSet");
+    method(cls, setKey, element);
+  }
+
+  static void
+  removeElementFromStringSet(std::string setKey, std::string element) {
+    static const auto cls = javaClassStatic();
+    static auto method = cls->getStaticMethod<void(std::string, std::string)>(
+        "removeElementFromStringSet");
+    method(cls, setKey, element);
+  }
+
+  static int getStringSetSize(std::string setKey) {
+    static const auto cls = javaClassStatic();
+    static auto method =
+        cls->getStaticMethod<JInteger(std::string)>("getStringSetSize");
+    const auto result = method(cls, setKey);
+    if (result) {
+      return result->value();
+    }
+    return 0;
+  }
 };
 
 namespace comm {
@@ -157,4 +183,24 @@
   NativeAndroidAccessProvider::runTask(
       [&]() { CommMMKVJavaClass::removeKeys(keys); });
 }
+
+void CommMMKV::addElementToStringSet(std::string setKey, std::string element) {
+  NativeAndroidAccessProvider::runTask(
+      [&]() { CommMMKVJavaClass::addElementToStringSet(setKey, element); });
+}
+
+void CommMMKV::removeElementFromStringSet(
+    std::string setKey,
+    std::string element) {
+  NativeAndroidAccessProvider::runTask([&]() {
+    CommMMKVJavaClass::removeElementFromStringSet(setKey, element);
+  });
+}
+
+int CommMMKV::getStringSetSize(std::string setKey) {
+  int result;
+  NativeAndroidAccessProvider::runTask(
+      [&]() { result = CommMMKVJavaClass::getStringSetSize(setKey); });
+  return result;
+}
 } // namespace comm
diff --git a/native/android/app/src/main/java/app/comm/android/fbjni/CommMMKV.java b/native/android/app/src/main/java/app/comm/android/fbjni/CommMMKV.java
--- a/native/android/app/src/main/java/app/comm/android/fbjni/CommMMKV.java
+++ b/native/android/app/src/main/java/app/comm/android/fbjni/CommMMKV.java
@@ -6,6 +6,7 @@
 import app.comm.android.fbjni.PlatformSpecificTools;
 import com.tencent.mmkv.MMKV;
 import java.util.Base64;
+import java.util.Set;
 
 public class CommMMKV {
   private static final int MMKV_ENCRYPTION_KEY_SIZE = 16;
@@ -135,4 +136,48 @@
     getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey)
         .removeValuesForKeys(keys);
   }
+
+  public static void addElementToStringSet(String setKey, String element) {
+    initialize();
+    MMKV mmkv = getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey);
+    mmkv.lock();
+    try {
+      Set<String> stringSet = mmkv.decodeStringSet(setKey);
+      if (stringSet != null) {
+        stringSet.add(element);
+      } else {
+        stringSet = Set.of(element);
+      }
+      mmkv.encode(setKey, stringSet);
+    } finally {
+      mmkv.unlock();
+    }
+  }
+
+  public static void removeElementFromStringSet(String setKey, String element) {
+    initialize();
+    MMKV mmkv = getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey);
+    mmkv.lock();
+    try {
+      Set<String> stringSet = mmkv.decodeStringSet(setKey);
+      if (stringSet == null) {
+        return;
+      }
+      stringSet.remove(element);
+      mmkv.encode(setKey, stringSet);
+    } finally {
+      mmkv.unlock();
+    }
+  }
+
+  public static int getStringSetSize(String setKey) {
+    initialize();
+    Set<String> stringSet = getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey)
+                                .decodeStringSet(setKey);
+    if (stringSet == null) {
+      return 0;
+    }
+
+    return stringSet.size();
+  }
 }
diff --git a/native/cpp/CommonCpp/Tools/CommMMKV.h b/native/cpp/CommonCpp/Tools/CommMMKV.h
--- a/native/cpp/CommonCpp/Tools/CommMMKV.h
+++ b/native/cpp/CommonCpp/Tools/CommMMKV.h
@@ -27,6 +27,11 @@
   static std::vector<std::string> getAllKeys();
   static void removeKeys(const std::vector<std::string> &keys);
 
+  static void addElementToStringSet(std::string setKey, std::string element);
+  static void
+  removeElementFromStringSet(std::string setKey, std::string element);
+  static int getStringSetSize(std::string setKey);
+
   class InitFromNSEForbiddenError : public std::runtime_error {
   public:
     using std::runtime_error::runtime_error;
diff --git a/native/ios/Comm/CommMMKV.mm b/native/ios/Comm/CommMMKV.mm
--- a/native/ios/Comm/CommMMKV.mm
+++ b/native/ios/Comm/CommMMKV.mm
@@ -212,4 +212,61 @@
   [mmkv removeValuesForKeys:keysObjC];
 }
 
+void CommMMKV::addElementToStringSet(std::string setKey, std::string element) {
+  NSString *setKeyObjC = [NSString stringWithCString:setKey.c_str()
+                                            encoding:NSUTF8StringEncoding];
+  NSString *elementObjC = [NSString stringWithCString:element.c_str()
+                                             encoding:NSUTF8StringEncoding];
+
+  CommMMKV::ScopedCommMMKVLock();
+  MMKV *mmkv = getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey);
+  NSMutableSet *stringSet =
+      [mmkv getObjectOfClass:NSMutableSet.class forKey:setKeyObjC];
+
+  if (stringSet) {
+    [stringSet addObject:elementObjC];
+  } else {
+    stringSet = [NSMutableSet setWithObject:elementObjC];
+  }
+
+  [mmkv setObject:stringSet forKey:setKeyObjC];
+}
+
+void CommMMKV::removeElementFromStringSet(
+    std::string setKey,
+    std::string element) {
+  NSString *setKeyObjC = [NSString stringWithCString:setKey.c_str()
+                                            encoding:NSUTF8StringEncoding];
+  NSString *elementObjC = [NSString stringWithCString:element.c_str()
+                                             encoding:NSUTF8StringEncoding];
+
+  CommMMKV::ScopedCommMMKVLock();
+  MMKV *mmkv = getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey);
+  NSMutableSet *stringSet =
+      [mmkv getObjectOfClass:NSMutableSet.class forKey:setKeyObjC];
+
+  if (!stringSet) {
+    return;
+  }
+
+  [stringSet removeObject:elementObjC];
+  [mmkv setObject:stringSet forKey:setKeyObjC];
+}
+
+int CommMMKV::getStringSetSize(std::string setKey) {
+  NSString *setKeyObjC = [NSString stringWithCString:setKey.c_str()
+                                            encoding:NSUTF8StringEncoding];
+
+  CommMMKV::ScopedCommMMKVLock();
+  MMKV *mmkv = getMMKVInstance(mmkvIdentifier, mmkvEncryptionKey);
+  NSMutableSet *stringSet =
+      [mmkv getObjectOfClass:NSMutableSet.class forKey:setKeyObjC];
+
+  if (!stringSet) {
+    return 0;
+  }
+
+  return [stringSet count];
+}
+
 } // namespace comm