diff --git a/ServerlessFunction/buildspec-prod.yml b/ServerlessFunction/buildspec-prod.yml
index 6b8ed3e..25d0161 100644
--- a/ServerlessFunction/buildspec-prod.yml
+++ b/ServerlessFunction/buildspec-prod.yml
@@ -5,7 +5,6 @@ env:
     SAM_CLI_TELEMETRY: 0
     GRADLE_OPTS: "-Dorg.gradle.daemon=false -Dorg.gradle.parallel=true -Dorg.gradle.caching=true"
     ENVIRONMENT: prod
-    STACK_NAME: group2-englishstudy-prod
 
 phases:
   install:
@@ -28,26 +27,17 @@ phases:
       - echo "Building SAM application for $ENVIRONMENT..."
       - cd $CODEBUILD_SRC_DIR/ServerlessFunction
       - sam build --parallel --cached
-      - echo "Build completed"
+      - echo "Packaging SAM application..."
+      - sam package --s3-bucket group2-englishstudy-pipeline-artifacts --s3-prefix sam-packages/$ENVIRONMENT --output-template-file packaged-template.yaml
 
   post_build:
     commands:
-      - echo "Deploying to $ENVIRONMENT environment..."
-      - cd $CODEBUILD_SRC_DIR/ServerlessFunction
-      - |
-        sam deploy \
-          --stack-name $STACK_NAME \
-          --s3-bucket group2-englishstudy-pipeline-artifacts \
-          --s3-prefix sam-deploy/prod \
-          --region ap-northeast-2 \
-          --capabilities CAPABILITY_IAM CAPABILITY_AUTO_EXPAND \
-          --no-confirm-changeset \
-          --no-fail-on-empty-changeset \
-          --parameter-overrides \
-            Environment=$ENVIRONMENT \
-            ExistingCognitoUserPoolId=ap-northeast-2_ezDwzFCzR \
-            ExistingCognitoClientId=4ns077jcr1pkue2vvisr6qdpu5
-      - echo "Deployment completed on $(date)"
+      - echo "Build completed on $(date)"
+
+artifacts:
+  files:
+    - packaged-template.yaml
+  base-directory: ServerlessFunction
 
 cache:
   paths:
diff --git a/ServerlessFunction/buildspec-test.yml b/ServerlessFunction/buildspec-test.yml
index e00db1d..6d75e4f 100644
--- a/ServerlessFunction/buildspec-test.yml
+++ b/ServerlessFunction/buildspec-test.yml
@@ -5,7 +5,6 @@ env:
     SAM_CLI_TELEMETRY: 0
     GRADLE_OPTS: "-Dorg.gradle.daemon=false -Dorg.gradle.parallel=true -Dorg.gradle.caching=true"
     ENVIRONMENT: test
-    STACK_NAME: group2-englishstudy-test
 
 phases:
   install:
@@ -28,23 +27,17 @@ phases:
       - echo "Building SAM application for $ENVIRONMENT..."
       - cd $CODEBUILD_SRC_DIR/ServerlessFunction
       - sam build --parallel --cached
-      - echo "Build completed"
+      - echo "Packaging SAM application..."
+      - sam package --s3-bucket group2-englishstudy-pipeline-artifacts --s3-prefix sam-packages/$ENVIRONMENT --output-template-file packaged-template.yaml
 
   post_build:
     commands:
-      - echo "Deploying to $ENVIRONMENT environment..."
-      - cd $CODEBUILD_SRC_DIR/ServerlessFunction
-      - |
-        sam deploy \
-          --stack-name $STACK_NAME \
-          --resolve-s3 \
-          --s3-prefix $STACK_NAME \
-          --region ap-northeast-2 \
-          --capabilities CAPABILITY_IAM CAPABILITY_AUTO_EXPAND \
-          --no-confirm-changeset \
-          --no-fail-on-empty-changeset \
-          --parameter-overrides Environment=$ENVIRONMENT ExistingCognitoUserPoolId=ap-northeast-2_ezDwzFCzR ExistingCognitoClientId=4ns077jcr1pkue2vvisr6qdpu5
-      - echo "Deployment completed on $(date)"
+      - echo "Build completed on $(date)"
+
+artifacts:
+  files:
+    - packaged-template.yaml
+  base-directory: ServerlessFunction
 
 cache:
   paths:
diff --git a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/ChatMessageHandler.java b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/ChatMessageHandler.java
index b156feb..07ef6ac 100644
--- a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/ChatMessageHandler.java
+++ b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/ChatMessageHandler.java
@@ -14,6 +14,8 @@
 import com.mzc.secondproject.serverless.domain.chatting.model.ChatMessage;
 import com.mzc.secondproject.serverless.domain.chatting.repository.ChatRoomRepository;
 import com.mzc.secondproject.serverless.domain.chatting.service.ChatMessageService;
+import com.mzc.secondproject.serverless.domain.user.model.User;
+import com.mzc.secondproject.serverless.domain.user.service.UserService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -29,21 +31,23 @@ public class ChatMessageHandler implements RequestHandler<APIGatewayProxyRequest
 	
 	private final ChatMessageService chatMessageService;
 	private final ChatRoomRepository chatRoomRepository;
+	private final UserService userService;
 	private final HandlerRouter router;
 	
 	/**
 	 * 기본 생성자 (Lambda에서 사용)
 	 */
 	public ChatMessageHandler() {
-		this(new ChatMessageService(), new ChatRoomRepository());
+		this(new ChatMessageService(), new ChatRoomRepository(), new UserService());
 	}
 	
 	/**
 	 * 의존성 주입 생성자 (테스트 용이성)
 	 */
-	public ChatMessageHandler(ChatMessageService chatMessageService, ChatRoomRepository chatRoomRepository) {
+	public ChatMessageHandler(ChatMessageService chatMessageService, ChatRoomRepository chatRoomRepository, UserService userService) {
 		this.chatMessageService = chatMessageService;
 		this.chatRoomRepository = chatRoomRepository;
+		this.userService = userService;
 		this.router = initRouter();
 	}
 	
@@ -69,6 +73,19 @@ private APIGatewayProxyResponseEvent sendMessage(APIGatewayProxyRequestEvent req
 			String messageType = dto.getMessageType() != null ? dto.getMessageType() : "TEXT";
 			String messageId = UUID.randomUUID().toString();
 			String now = Instant.now().toString();
+
+			String nickname = "Unknown";
+			try {
+				User user = userService.getUserProfile(userId);
+				if (user != null && user.getNickname() != null) {
+					nickname = user.getNickname();
+				} else {
+					nickname = "User-" + userId.substring(0, 5);
+				}
+			} catch (Exception e) {
+				logger.warn("닉네임 조회 실패: {}", e.getMessage());
+				nickname = "User-" + userId.substring(0, 5);
+			}
 			
 			ChatMessage message = ChatMessage.builder()
 					.pk("ROOM#" + roomId)
@@ -80,6 +97,7 @@ private APIGatewayProxyResponseEvent sendMessage(APIGatewayProxyRequestEvent req
 					.messageId(messageId)
 					.roomId(roomId)
 					.userId(userId)
+					.nickname(nickname)
 					.content(dto.getContent())
 					.messageType(messageType)
 					.createdAt(now)
diff --git a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/websocket/WebSocketConnectHandler.java b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/websocket/WebSocketConnectHandler.java
index 7b674a4..67950d5 100644
--- a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/websocket/WebSocketConnectHandler.java
+++ b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/handler/websocket/WebSocketConnectHandler.java
@@ -56,7 +56,42 @@ public Map<String, Object> handleRequest(Map<String, Object> event, Context cont
 			RoomToken token = optToken.get();
 			String userId = token.getUserId();
 			String roomId = token.getRoomId();
-			
+			String nickname = "Unknown";
+
+			// Cognito Authorizer에서 닉네임 추출
+			try {
+				if (event.containsKey("requestContext")) {
+					Map<String, Object> reqCtx = (Map<String, Object>) event.get("requestContext");
+
+					if (reqCtx.containsKey("authorizer")) {
+						Map<String, Object> auth = (Map<String, Object>) reqCtx.get("authorizer");
+
+						Map<String, Object> claims = auth;
+						if (auth.containsKey("claims")) {
+							claims = (Map<String, Object>) auth.get("claims");
+						} else if (auth.containsKey("principalId")) {
+							claims = auth;
+						}
+
+						if (claims != null) {
+							if (claims.get("nickname") != null) {
+								nickname = (String) claims.get("nickname");
+							} else if (claims.get("custom:nickname") != null) {
+								nickname = (String) claims.get("custom:nickname");
+							} else if (claims.get("name") != null) {
+								nickname = (String) claims.get("name");
+							}
+						}
+					}
+				}
+				// 닉네임 못찾았으면 UserId 앞부분 표시
+				if ("Unknown".equals(nickname) && userId != null && userId.length() > 5) {
+					nickname = "User-" + userId.substring(0, 5);
+				}
+			} catch (Exception ex) {
+				logger.warn("닉네임 표시 실패: {}", ex.getMessage());
+			}
+
 			// 같은 방에서 기존 연결 삭제 (새로고침 시 중복 연결 방지)
 			connectionRepository.deleteUserConnectionsInRoom(userId, roomId);
 			
@@ -72,6 +107,7 @@ public Map<String, Object> handleRequest(Map<String, Object> event, Context cont
 					.gsi2sk("CONN#" + connectionId)
 					.connectionId(connectionId)
 					.userId(userId)
+					.nickname(nickname)
 					.roomId(roomId)
 					.connectedAt(now)
 					.ttl(ttl)
diff --git a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/model/Connection.java b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/model/Connection.java
index 7c13039..5aa02e2 100644
--- a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/model/Connection.java
+++ b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/model/Connection.java
@@ -22,6 +22,7 @@ public class Connection {
 	
 	private String connectionId;
 	private String userId;
+	private String nickname;
 	private String roomId;
 	private String connectedAt;
 	private Long ttl;           // 10분 후 자동 삭제
diff --git a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/repository/WordChainSessionRepository.java b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/repository/WordChainSessionRepository.java
index ca39ddf..b871987 100644
--- a/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/repository/WordChainSessionRepository.java
+++ b/ServerlessFunction/src/main/java/com/mzc/secondproject/serverless/domain/chatting/repository/WordChainSessionRepository.java
@@ -5,6 +5,7 @@
 import com.mzc.secondproject.serverless.domain.chatting.model.WordChainSession;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import software.amazon.awssdk.enhanced.dynamodb.DynamoDbIndex;
 import software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable;
 import software.amazon.awssdk.enhanced.dynamodb.Key;
 import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
@@ -19,16 +20,20 @@ public class WordChainSessionRepository {
 
 	private static final Logger logger = LoggerFactory.getLogger(WordChainSessionRepository.class);
 	private static final String TABLE_NAME = EnvConfig.getRequired("CHAT_TABLE_NAME");
+	private static final String GSI1_INDEX_NAME = "GSI1";
 
 	private final DynamoDbTable<WordChainSession> table;
+	private final DynamoDbIndex<WordChainSession> gsi1Index;
 
 	public WordChainSessionRepository() {
 		this.table = AwsClients.dynamoDbEnhanced()
 				.table(TABLE_NAME, TableSchema.fromBean(WordChainSession.class));
+		this.gsi1Index = table.index(GSI1_INDEX_NAME);
 	}
 
 	public WordChainSessionRepository(DynamoDbTable<WordChainSession> table) {
 		this.table = table;
+		this.gsi1Index = table.index(GSI1_INDEX_NAME);
 	}
 
 	/**
@@ -52,16 +57,16 @@ public Optional<WordChainSession> findById(String sessionId) {
 	}
 
 	/**
-	 * 방의 활성 세션 조회
+	 * 방의 활성 세션 조회 (GSI1 인덱스 사용)
 	 */
 	public Optional<WordChainSession> findActiveByRoomId(String roomId) {
-		return table.query(QueryConditional.sortBeginsWith(
+		return gsi1Index.query(QueryConditional.sortBeginsWith(
 						Key.builder()
 								.partitionValue("ROOM#" + roomId)
 								.sortValue("WORDCHAIN#")
 								.build()))
-				.items()
 				.stream()
+				.flatMap(page -> page.items().stream())
 				.filter(WordChainSession::isActive)
 				.findFirst();
 	}
diff --git a/ServerlessFunction/template.yaml b/ServerlessFunction/template.yaml
index 225dc20..ed741ae 100644
--- a/ServerlessFunction/template.yaml
+++ b/ServerlessFunction/template.yaml
@@ -142,10 +142,10 @@ Resources:
           ResponseTemplates:
             application/json: '{"message": "Token expired", "statusCode": 401}'
       Auth:
-        DefaultAuthorizer: CognitoAuthorizer
+        DefaultAuthorizer: CognitoAuthV2
         AddDefaultAuthorizerToCorsPreflight: false
         Authorizers:
-          CognitoAuthorizer:
+          CognitoAuthV2:
             UserPoolArn: !Sub "arn:aws:cognito-idp:${AWS::Region}:${AWS::AccountId}:userpool/${ExistingCognitoUserPoolId}"
             Identity:
               Header: Authorization
@@ -402,7 +402,7 @@ Resources:
             Path: /chat/rooms
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetRooms:
           Type: Api
           Properties:
@@ -410,7 +410,7 @@ Resources:
             Path: /chat/rooms
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetRoom:
           Type: Api
           Properties:
@@ -418,7 +418,7 @@ Resources:
             Path: /chat/rooms/{roomId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         DeleteRoom:
           Type: Api
           Properties:
@@ -426,7 +426,7 @@ Resources:
             Path: /chat/rooms/{roomId}
             Method: DELETE
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         JoinRoom:
           Type: Api
           Properties:
@@ -434,7 +434,7 @@ Resources:
             Path: /chat/rooms/{roomId}/join
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         LeaveRoom:
           Type: Api
           Properties:
@@ -442,7 +442,7 @@ Resources:
             Path: /chat/rooms/{roomId}/leave
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   GameFunction:
     Type: AWS::Serverless::Function
@@ -489,7 +489,7 @@ Resources:
             Path: /chat/rooms/{roomId}/game/start
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         StopGame:
           Type: Api
           Properties:
@@ -497,7 +497,7 @@ Resources:
             Path: /chat/rooms/{roomId}/game/stop
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetGameStatus:
           Type: Api
           Properties:
@@ -505,7 +505,7 @@ Resources:
             Path: /chat/rooms/{roomId}/game/status
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetScores:
           Type: Api
           Properties:
@@ -513,7 +513,7 @@ Resources:
             Path: /chat/rooms/{roomId}/game/scores
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   # 끝말잇기(Word Chain) 게임 핸들러
   WordChainFunction:
@@ -546,7 +546,7 @@ Resources:
             Path: /chat/rooms/{roomId}/wordchain/start
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         SubmitWord:
           Type: Api
           Properties:
@@ -554,7 +554,7 @@ Resources:
             Path: /chat/rooms/{roomId}/wordchain/submit
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         HandleTimeout:
           Type: Api
           Properties:
@@ -562,7 +562,7 @@ Resources:
             Path: /chat/rooms/{roomId}/wordchain/timeout
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         StopWordChain:
           Type: Api
           Properties:
@@ -570,7 +570,7 @@ Resources:
             Path: /chat/rooms/{roomId}/wordchain/stop
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetWordChainStatus:
           Type: Api
           Properties:
@@ -578,7 +578,7 @@ Resources:
             Path: /chat/rooms/{roomId}/wordchain/status
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   # 게임 자동 종료 Lambda (EventBridge Scheduler에 의해 호출)
   GameAutoCloseFunction:
@@ -666,7 +666,7 @@ Resources:
             Path: /chat/rooms/{roomId}/messages
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetMessages:
           Type: Api
           Properties:
@@ -674,7 +674,7 @@ Resources:
             Path: /chat/rooms/{roomId}/messages
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetMessage:
           Type: Api
           Properties:
@@ -682,7 +682,7 @@ Resources:
             Path: /chat/rooms/{roomId}/messages/{messageId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   ChatVoiceFunction:
     Type: AWS::Serverless::Function
@@ -712,7 +712,7 @@ Resources:
             Path: /chat/voice/synthesize
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   #############################################
   # Vocabulary Lambda Functions
@@ -816,7 +816,7 @@ Resources:
             Path: /vocab/wrong-answers
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetUserWords:
           Type: Api
           Properties:
@@ -824,7 +824,7 @@ Resources:
             Path: /vocab/user-words
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetUserWord:
           Type: Api
           Properties:
@@ -832,7 +832,7 @@ Resources:
             Path: /vocab/user-words/{wordId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         UpdateUserWord:
           Type: Api
           Properties:
@@ -840,7 +840,7 @@ Resources:
             Path: /vocab/user-words/{wordId}
             Method: PUT
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         UpdateUserWordTag:
           Type: Api
           Properties:
@@ -848,7 +848,7 @@ Resources:
             Path: /vocab/user-words/{wordId}/tag
             Method: PATCH
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         UpdateUserWordStatus:
           Type: Api
           Properties:
@@ -856,7 +856,7 @@ Resources:
             Path: /vocab/user-words/{wordId}/status
             Method: PATCH
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   WordGroupFunction:
     Type: AWS::Serverless::Function
@@ -878,7 +878,7 @@ Resources:
             Path: /vocab/groups
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetGroups:
           Type: Api
           Properties:
@@ -886,7 +886,7 @@ Resources:
             Path: /vocab/groups
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetGroupDetail:
           Type: Api
           Properties:
@@ -894,7 +894,7 @@ Resources:
             Path: /vocab/groups/{groupId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         UpdateGroup:
           Type: Api
           Properties:
@@ -902,7 +902,7 @@ Resources:
             Path: /vocab/groups/{groupId}
             Method: PUT
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         DeleteGroup:
           Type: Api
           Properties:
@@ -910,7 +910,7 @@ Resources:
             Path: /vocab/groups/{groupId}
             Method: DELETE
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         AddWordToGroup:
           Type: Api
           Properties:
@@ -918,7 +918,7 @@ Resources:
             Path: /vocab/groups/{groupId}/words/{wordId}
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         RemoveWordFromGroup:
           Type: Api
           Properties:
@@ -926,7 +926,7 @@ Resources:
             Path: /vocab/groups/{groupId}/words/{wordId}
             Method: DELETE
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   DailyStudyFunction:
     Type: AWS::Serverless::Function
@@ -953,7 +953,7 @@ Resources:
             Path: /vocab/daily
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         MarkWordLearned:
           Type: Api
           Properties:
@@ -961,7 +961,7 @@ Resources:
             Path: /vocab/daily/words/{wordId}/learned
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   TestFunction:
     Type: AWS::Serverless::Function
@@ -991,7 +991,7 @@ Resources:
             Path: /vocab/test/start
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         SubmitAnswer:
           Type: Api
           Properties:
@@ -999,7 +999,7 @@ Resources:
             Path: /vocab/test/submit
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetTestResults:
           Type: Api
           Properties:
@@ -1007,7 +1007,7 @@ Resources:
             Path: /vocab/test/results
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetTestResultDetail:
           Type: Api
           Properties:
@@ -1015,7 +1015,7 @@ Resources:
             Path: /vocab/test/results/{testId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetTestedWords:
           Type: Api
           Properties:
@@ -1023,7 +1023,7 @@ Resources:
             Path: /vocab/test/tested-words
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   StatsFunction:
     Type: AWS::Serverless::Function
@@ -1045,7 +1045,7 @@ Resources:
             Path: /vocab/stats
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetDailyStats:
           Type: Api
           Properties:
@@ -1053,7 +1053,7 @@ Resources:
             Path: /vocab/stats/daily
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetWeaknessAnalysis:
           Type: Api
           Properties:
@@ -1061,7 +1061,7 @@ Resources:
             Path: /vocab/stats/weakness
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   VocabVoiceFunction:
     Type: AWS::Serverless::Function
@@ -1143,7 +1143,7 @@ Resources:
             Path: /stats/daily
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetWeeklyStats:
           Type: Api
           Properties:
@@ -1151,7 +1151,7 @@ Resources:
             Path: /stats/weekly
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetMonthlyStats:
           Type: Api
           Properties:
@@ -1159,7 +1159,7 @@ Resources:
             Path: /stats/monthly
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetTotalStats:
           Type: Api
           Properties:
@@ -1167,7 +1167,7 @@ Resources:
             Path: /stats/total
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetDashboard:
           Type: Api
           Properties:
@@ -1175,7 +1175,7 @@ Resources:
             Path: /stats/dashboard
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetStatsHistory:
           Type: Api
           Properties:
@@ -1183,7 +1183,7 @@ Resources:
             Path: /stats/history
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   # Badge Lambda Function
   BadgeFunction:
@@ -1213,7 +1213,7 @@ Resources:
             Path: /badges
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetEarnedBadges:
           Type: Api
           Properties:
@@ -1221,7 +1221,7 @@ Resources:
             Path: /badges/earned
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   #############################################
   # Grammar Lambda Functions
@@ -1268,7 +1268,7 @@ Resources:
             Path: /grammar/check
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GrammarConversation:
           Type: Api
           Properties:
@@ -1276,7 +1276,7 @@ Resources:
             Path: /grammar/conversation
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetSessions:
           Type: Api
           Properties:
@@ -1284,7 +1284,7 @@ Resources:
             Path: /grammar/sessions
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         GetSessionDetail:
           Type: Api
           Properties:
@@ -1292,7 +1292,7 @@ Resources:
             Path: /grammar/sessions/{sessionId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         DeleteSession:
           Type: Api
           Properties:
@@ -1300,7 +1300,7 @@ Resources:
             Path: /grammar/sessions/{sessionId}
             Method: DELETE
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   #############################################
   # Grammar WebSocket API (Streaming)
@@ -1564,7 +1564,7 @@ Resources:
             Path: /opic/sessions
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         # 세션 조회
         GetSession:
           Type: Api
@@ -1573,7 +1573,7 @@ Resources:
             Path: /opic/sessions/{sessionId}
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         # 세션 목록 조회
         GetSessions:
           Type: Api
@@ -1582,7 +1582,7 @@ Resources:
             Path: /opic/sessions
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         # 다음 질문 조회
         GetNextQuestion:
           Type: Api
@@ -1591,7 +1591,7 @@ Resources:
             Path: /opic/sessions/{sessionId}/questions/next
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         # 답변 제출
         SubmitAnswer:
           Type: Api
@@ -1600,7 +1600,7 @@ Resources:
             Path: /opic/sessions/{sessionId}/answers
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         # 세션 완료
         CompleteSession:
           Type: Api
@@ -1609,7 +1609,7 @@ Resources:
             Path: /opic/sessions/{sessionId}/complete
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         # 음성 업로드 Presigned URL
         GetUploadUrl:
           Type: Api
@@ -1618,7 +1618,7 @@ Resources:
             Path: /opic/sessions/{sessionId}/upload-url
             Method: GET
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   #############################################
   # Speaking Lambda Functions
@@ -1660,7 +1660,7 @@ Resources:
             Path: /speaking/chat
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
         SpeakingReset:
           Type: Api
           Properties:
@@ -1668,7 +1668,7 @@ Resources:
             Path: /speaking/reset
             Method: POST
             Auth:
-              Authorizer: CognitoAuthorizer
+              Authorizer: CognitoAuthV2
 
   #############################################
   # DynamoDB Tables