diff --git a/stream-chat-android-client/src/test/java/io/getstream/chat/android/client/UsersApiCallsTests.kt b/stream-chat-android-client/src/test/java/io/getstream/chat/android/client/UsersApiCallsTests.kt
index 282ae27ca2e..15dcf1d19b3 100644
--- a/stream-chat-android-client/src/test/java/io/getstream/chat/android/client/UsersApiCallsTests.kt
+++ b/stream-chat-android-client/src/test/java/io/getstream/chat/android/client/UsersApiCallsTests.kt
@@ -24,6 +24,7 @@ import io.getstream.chat.android.models.Filters
 import io.getstream.chat.android.models.Flag
 import io.getstream.chat.android.models.Mute
 import io.getstream.chat.android.models.User
+import io.getstream.chat.android.randomString
 import io.getstream.chat.android.test.TestCoroutineExtension
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.BeforeEach
@@ -123,12 +124,22 @@ internal class UsersApiCallsTests {
             date,
             date,
         )
+        val reason = randomString()
+        val customData = mapOf(randomString() to randomString())
 
         Mockito.`when`(
-            mock.api.flagUser(targetUserId),
+            mock.api.flagUser(
+                userId = targetUserId,
+                reason = reason,
+                customData = customData,
+            ),
         ).thenReturn(RetroSuccess(flag).toRetrofitCall())
 
-        val result = client.flagUser(targetUserId).await()
+        val result = client.flagUser(
+            userId = targetUserId,
+            reason = reason,
+            customData = customData,
+        ).await()
 
         verifySuccess(result, flag)
     }
@@ -151,12 +162,22 @@ internal class UsersApiCallsTests {
             date,
             date,
         )
+        val reason = randomString()
+        val customData = mapOf(randomString() to randomString())
 
         Mockito.`when`(
-            mock.api.flagUser(targetUserId),
+            mock.api.flagUser(
+                userId = targetUserId,
+                reason = reason,
+                customData = customData,
+            ),
         ).thenReturn(RetroSuccess(flag).toRetrofitCall())
 
-        val result = client.flagUser(targetUserId).await()
+        val result = client.flagUser(
+            userId = targetUserId,
+            reason = reason,
+            customData = customData,
+        ).await()
 
         verifySuccess(result, flag)
     }
@@ -178,12 +199,22 @@ internal class UsersApiCallsTests {
             date,
             date,
         )
+        val reason = randomString()
+        val customData = mapOf(randomString() to randomString())
 
         Mockito.`when`(
-            mock.api.flagMessage(targetMessageId),
+            mock.api.flagMessage(
+                messageId = targetMessageId,
+                reason = reason,
+                customData = customData,
+            ),
         ).thenReturn(RetroSuccess(flag).toRetrofitCall())
 
-        val result = client.flagMessage(targetMessageId).await()
+        val result = client.flagMessage(
+            messageId = targetMessageId,
+            reason = reason,
+            customData = customData,
+        ).await()
 
         verifySuccess(result, flag)
     }
diff --git a/stream-chat-android-ui-components/src/test/kotlin/io/getstream/chat/android/ui/viewmodels/messages/MessageListViewModelTest.kt b/stream-chat-android-ui-components/src/test/kotlin/io/getstream/chat/android/ui/viewmodels/messages/MessageListViewModelTest.kt
index 1676ceb98a0..f8f54656d3d 100644
--- a/stream-chat-android-ui-components/src/test/kotlin/io/getstream/chat/android/ui/viewmodels/messages/MessageListViewModelTest.kt
+++ b/stream-chat-android-ui-components/src/test/kotlin/io/getstream/chat/android/ui/viewmodels/messages/MessageListViewModelTest.kt
@@ -30,6 +30,7 @@ import io.getstream.chat.android.models.TypingEvent
 import io.getstream.chat.android.models.User
 import io.getstream.chat.android.randomChannelUserRead
 import io.getstream.chat.android.randomInt
+import io.getstream.chat.android.randomString
 import io.getstream.chat.android.state.plugin.config.StatePluginConfig
 import io.getstream.chat.android.state.plugin.factory.StreamStatePluginFactory
 import io.getstream.chat.android.state.plugin.internal.StatePlugin
@@ -157,17 +158,32 @@ internal class MessageListViewModelTest {
         val messages = listOf(messageToFlag, message2)
         val messageState = MessagesState.Result(messages)
         val chatClient = MockChatClientBuilder().build()
+        val reason = randomString()
+        val customData = mapOf(randomString() to randomString())
 
         val viewModel = Fixture(chatClient = chatClient)
             .givenCurrentUser()
             .givenChannelQuery()
             .givenChannelState(messageState = messageState, messages = messages)
-            .givenFlagMessage(message = messageToFlag)
-            .get()
+            .givenFlagMessage(
+                message = messageToFlag,
+                reason = reason,
+                customData = customData,
+            ).get()
 
-        viewModel.onEvent(MessageListViewModel.Event.FlagMessage(messageToFlag))
+        viewModel.onEvent(
+            MessageListViewModel.Event.FlagMessage(
+                message = messageToFlag,
+                reason = reason,
+                customData = customData,
+            ),
+        )
 
-        verify(chatClient).flagMessage(messageId = messageToFlag.id)
+        verify(chatClient).flagMessage(
+            messageId = messageToFlag.id,
+            reason = reason,
+            customData = customData,
+        )
     }
 
     @Test
@@ -251,8 +267,14 @@ internal class MessageListViewModelTest {
             whenever(chatClient.queryChannel(any(), any(), any(), any())) doReturn channel.asCall()
         }
 
-        fun givenFlagMessage(message: Message) = apply {
-            whenever(chatClient.flagMessage(message.id)) doReturn mock()
+        fun givenFlagMessage(message: Message, reason: String, customData: Map<String, String>) = apply {
+            whenever(
+                chatClient.flagMessage(
+                    messageId = message.id,
+                    reason = reason,
+                    customData = customData,
+                ),
+            ) doReturn mock()
         }
 
         fun givenDeleteMessage() = apply {