diff --git a/backend/src/main/java/com/openisle/controller/ReactionController.java b/backend/src/main/java/com/openisle/controller/ReactionController.java
index b7824a8ca..062fe313a 100644
--- a/backend/src/main/java/com/openisle/controller/ReactionController.java
+++ b/backend/src/main/java/com/openisle/controller/ReactionController.java
@@ -27,7 +27,6 @@ public class ReactionController {
     }
 
     @PostMapping("/posts/{postId}/reactions")
-    @Transactional
     public ResponseEntity<ReactionDto> reactToPost(@PathVariable Long postId,
                                                   @RequestBody ReactionRequest req,
                                                   Authentication auth) {
@@ -41,7 +40,6 @@ public class ReactionController {
     }
 
     @PostMapping("/comments/{commentId}/reactions")
-    @Transactional
     public ResponseEntity<ReactionDto> reactToComment(@PathVariable Long commentId,
                                                      @RequestBody ReactionRequest req,
                                                      Authentication auth) {
diff --git a/backend/src/main/java/com/openisle/service/CommentService.java b/backend/src/main/java/com/openisle/service/CommentService.java
index 16820f4d0..70eb764f6 100644
--- a/backend/src/main/java/com/openisle/service/CommentService.java
+++ b/backend/src/main/java/com/openisle/service/CommentService.java
@@ -70,6 +70,7 @@ public class CommentService {
         return comment;
     }
 
+    @Transactional
     public Comment addReply(String username, Long parentId, String content) {
         long recent = commentRepository.countByAuthorAfter(username,
                 java.time.LocalDateTime.now().minusMinutes(1));
@@ -154,7 +155,7 @@ public class CommentService {
         return commentRepository.findLastCommentTime(post);
     }
 
-    @org.springframework.transaction.annotation.Transactional
+    @Transactional
     public void deleteComment(String username, Long id) {
         User user = userRepository.findByUsername(username)
                 .orElseThrow(() -> new com.openisle.exception.NotFoundException("User not found"));
@@ -166,7 +167,7 @@ public class CommentService {
         deleteCommentCascade(comment);
     }
 
-    @org.springframework.transaction.annotation.Transactional
+    @Transactional
     public void deleteCommentCascade(Comment comment) {
         List<Comment> replies = commentRepository.findByParentOrderByCreatedAtAsc(comment);
         for (Comment c : replies) {
diff --git a/backend/src/main/java/com/openisle/service/ReactionService.java b/backend/src/main/java/com/openisle/service/ReactionService.java
index 393de62b3..b6cda46f5 100644
--- a/backend/src/main/java/com/openisle/service/ReactionService.java
+++ b/backend/src/main/java/com/openisle/service/ReactionService.java
@@ -15,6 +15,7 @@ import com.openisle.service.EmailSender;
 import lombok.RequiredArgsConstructor;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 @Service
 @RequiredArgsConstructor
@@ -29,6 +30,7 @@ public class ReactionService {
     @Value("${app.website-url}")
     private String websiteUrl;
 
+    @Transactional
     public Reaction reactToPost(String username, Long postId, ReactionType type) {
         User user = userRepository.findByUsername(username)
                 .orElseThrow(() -> new com.openisle.exception.NotFoundException("User not found"));
@@ -51,6 +53,7 @@ public class ReactionService {
         return reaction;
     }
 
+    @Transactional
     public Reaction reactToComment(String username, Long commentId, ReactionType type) {
         User user = userRepository.findByUsername(username)
                 .orElseThrow(() -> new com.openisle.exception.NotFoundException("User not found"));