diff --git a/backend/src/modules/comment/comment.dto.ts b/backend/src/modules/comment/comment.dto.ts
index 222a220..390be45 100644
--- a/backend/src/modules/comment/comment.dto.ts
+++ b/backend/src/modules/comment/comment.dto.ts
@@ -6,7 +6,9 @@ import {
   IsInt,
   Min,
   Max,
+  MaxLength,
 } from 'class-validator';
+import { Type } from 'class-transformer';
 
 interface CommentEntity {
   id: string;
@@ -29,7 +31,7 @@ interface CommentEntity {
 
 export class CreateCommentDto {
   @IsString()
-  @Max(5000)
+  @MaxLength(5000)
   content: string;
 
   @IsUUID()
@@ -47,7 +49,7 @@ export class CreateCommentDto {
 
 export class UpdateCommentDto {
   @IsString()
-  @Max(5000)
+  @MaxLength(5000)
   @IsOptional()
   content?: string;
 
@@ -118,12 +120,14 @@ export class FindCommentsDto {
   @IsInt()
   @Min(1)
   @IsOptional()
+  @Type(() => Number)
   page?: number = 1;
 
   @IsInt()
   @Min(1)
   @Max(100)
   @IsOptional()
+  @Type(() => Number)
   limit?: number = 20;
 }
 
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index e887337..99bc8e3 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -625,7 +625,14 @@ export interface CreateReactionDto {
 export async function fetchComments(params: FindCommentsParams = {}): Promise<CommentsResponse> {
   const searchParams = new URLSearchParams();
   
-  Object.entries(params).forEach(([key, value]) => {
+  // Map parentCommentId to parentId for backend compatibility
+  const backendParams = { ...params };
+  if (backendParams.parentCommentId) {
+    backendParams.parentId = backendParams.parentCommentId;
+    delete backendParams.parentCommentId;
+  }
+  
+  Object.entries(backendParams).forEach(([key, value]) => {
     if (value !== undefined && value !== null) {
       if (typeof value === 'number') {
         searchParams.append(key, value.toString());
@@ -639,18 +646,55 @@ export async function fetchComments(params: FindCommentsParams = {}): Promise<Co
   if (!response.ok) {
     throw new Error('Failed to fetch comments');
   }
-  return response.json();
+  
+  const data = await response.json();
+  
+  // Map backend response to frontend interface
+  const mappedData = data.map((comment: any) => ({
+    ...comment,
+    parentCommentId: comment.parentId,
+    // Ensure reactions object exists
+    reactions: {
+      likes: comment.likeCount || 0,
+      dislikes: comment.dislikeCount || 0,
+    },
+  }));
+  
+  return {
+    data: mappedData,
+    total: mappedData.length,
+  };
 }
 
 export async function createComment(dto: CreateCommentDto): Promise<Comment> {
+  // Map parentCommentId to parentId for backend compatibility
+  const backendDto = {
+    content: dto.content,
+    articleId: dto.articleId,
+    liveBlogId: dto.liveBlogId,
+    parentId: dto.parentCommentId,
+  };
+  
   const response = await authFetch(`${API_BASE_URL}/comments`, {
     method: 'POST',
-    body: JSON.stringify(dto),
+    body: JSON.stringify(backendDto),
   });
   if (!response.ok) {
     throw new Error('Failed to create comment');
   }
-  return response.json();
+  
+  const comment = await response.json();
+  
+  // Map backend response to frontend interface
+  return {
+    ...comment,
+    parentCommentId: comment.parentId,
+    // Ensure reactions object exists
+    reactions: {
+      likes: comment.likeCount || 0,
+      dislikes: comment.dislikeCount || 0,
+    },
+  };
 }
 
 export async function updateComment(id: string, dto: UpdateCommentDto): Promise<Comment> {