diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000..3c3629e6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/sprint-mission-3 b/sprint-mission-3
new file mode 160000
index 00000000..fffc1765
--- /dev/null
+++ b/sprint-mission-3
@@ -0,0 +1 @@
+Subproject commit fffc176556abcc21a77068d48bb997dcb98197d1
diff --git a/sprint-mission-4/.env.example b/sprint-mission-4/.env.example
new file mode 100644
index 00000000..6dac7779
--- /dev/null
+++ b/sprint-mission-4/.env.example
@@ -0,0 +1,5 @@
+PORT=3000
+JWT_ACCESS_TOKEN_SECRET=your_jwt_access_token_secret
+JWT_REFRESH_TOKEN_SECRET=your_jwt_refresh_token_secret
+ACCESS_TOKEN_COOKIE_NAME=access-token
+REFRESH_TOKEN_COOKIE_NAME=refresh-token
diff --git a/sprint-mission-4/.gitignore b/sprint-mission-4/.gitignore
new file mode 100644
index 00000000..233b2778
--- /dev/null
+++ b/sprint-mission-4/.gitignore
@@ -0,0 +1,16 @@
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+!.vscode/*.code-snippets
+!*.code-workspace
+
+# Built Visual Studio Code Extensions
+*.vsix
+node_modules/
+package-lock.json
+test.http
+.githooks/
+.vscode/
+.env
\ No newline at end of file
diff --git a/sprint-mission-4/app.js b/sprint-mission-4/app.js
new file mode 100644
index 00000000..eb7d80f7
--- /dev/null
+++ b/sprint-mission-4/app.js
@@ -0,0 +1,55 @@
+import express from 'express';
+import cookieParser from 'cookie-parser';
+import cors from 'cors';
+import helmet from 'helmet';
+import authRouter from './routers/auth.router.js';
+import usersRouter from './routers/users.router.js';
+import productsRouter from './routers/products.router.js';
+import articlesRouter from './routers/articles.router.js';
+import postsRouter from './routers/posts.router.js'; // 새로 만든 posts.router.js 임포트
+import commentsRouter from './routers/comments.router.js';
+import { PORT } from './lib/constants.js';
+
+const app = express();
+
+// Security middleware
+app.use(helmet());
+
+// CORS middleware
+app.use(cors());
+
+// Middleware for logging requests
+app.use((req, res, next) => {
+  console.log(`${new Date().toISOString()} - ${req.method} ${req.url}`);
+  next();
+});
+
+app.use(cookieParser());
+app.use(express.json());
+
+// API routes
+app.use('/api/auth', authRouter);
+app.use('/api/users', usersRouter);
+app.use('/api/products', productsRouter);
+app.use('/api/articles', articlesRouter);
+app.use('/api/posts', postsRouter); // /api/posts 경로에 새로운 postsRouter 할당
+app.use('/api/comments', commentsRouter);
+
+// 404 handler for unmatched routes
+app.use((req, res) => {
+  res.status(404).json({ message: 'Route not found' });
+});
+
+// Global error handler
+app.use((err, req, res, next) => {
+  // Log the error for debugging purposes. Consider using a logger like Winston.
+  console.error(err);
+
+  // Send a generic error message to the client
+  // Avoid sending stack trace in production
+  res.status(500).json({ message: 'Internal server error' });
+});
+
+app.listen(PORT, () => {
+  console.log(`Server is running on http://localhost:${PORT}`);
+});
diff --git a/sprint-mission-4/dev.db b/sprint-mission-4/dev.db
new file mode 100644
index 00000000..7e2772fc
Binary files /dev/null and b/sprint-mission-4/dev.db differ
diff --git a/sprint-mission-4/lib/constants.js b/sprint-mission-4/lib/constants.js
new file mode 100644
index 00000000..af8e48a9
--- /dev/null
+++ b/sprint-mission-4/lib/constants.js
@@ -0,0 +1,21 @@
+import dotenv from 'dotenv';
+
+dotenv.config();
+
+const NODE_ENV = process.env.NODE_ENV || 'development';
+const PORT = process.env.PORT || 3000;
+const JWT_ACCESS_TOKEN_SECRET =
+  process.env.JWT_ACCESS_TOKEN_SECRET || 'your_jwt_access_token_secret';
+const JWT_REFRESH_TOKEN_SECRET =
+  process.env.JWT_REFRESH_TOKEN_SECRET || 'your_jwt_refresh_token_secret';
+const ACCESS_TOKEN_COOKIE_NAME = 'access-token';
+const REFRESH_TOKEN_COOKIE_NAME = 'refresh-token';
+
+export {
+  NODE_ENV,
+  PORT,
+  JWT_ACCESS_TOKEN_SECRET,
+  JWT_REFRESH_TOKEN_SECRET,
+  ACCESS_TOKEN_COOKIE_NAME,
+  REFRESH_TOKEN_COOKIE_NAME,
+};
diff --git a/sprint-mission-4/lib/prisma.js b/sprint-mission-4/lib/prisma.js
new file mode 100644
index 00000000..4e54f7a7
--- /dev/null
+++ b/sprint-mission-4/lib/prisma.js
@@ -0,0 +1,5 @@
+import { PrismaClient } from '@prisma/client';
+
+const prisma = new PrismaClient();
+
+export default prisma;
diff --git a/sprint-mission-4/lib/token.js b/sprint-mission-4/lib/token.js
new file mode 100644
index 00000000..66909d19
--- /dev/null
+++ b/sprint-mission-4/lib/token.js
@@ -0,0 +1,27 @@
+import jwt from 'jsonwebtoken';
+import {
+  JWT_ACCESS_TOKEN_SECRET,
+  JWT_REFRESH_TOKEN_SECRET,
+} from './constants.js';
+
+function generateTokens(userId) {
+  const accessToken = jwt.sign({ id: userId }, JWT_ACCESS_TOKEN_SECRET, {
+    expiresIn: '1h',
+  });
+  const refreshToken = jwt.sign({ id: userId }, JWT_REFRESH_TOKEN_SECRET, {
+    expiresIn: '1d',
+  });
+  return { accessToken, refreshToken };
+}
+
+function verifyAccessToken(token) {
+  const decoded = jwt.verify(token, JWT_ACCESS_TOKEN_SECRET);
+  return { userId: decoded.id };
+}
+
+function verifyRefreshToken(token) {
+  const decoded = jwt.verify(token, JWT_REFRESH_TOKEN_SECRET);
+  return { userId: decoded.id };
+}
+
+export { generateTokens, verifyAccessToken, verifyRefreshToken };
diff --git a/sprint-mission-4/middlewares/auth.middleware.js b/sprint-mission-4/middlewares/auth.middleware.js
new file mode 100644
index 00000000..f6ec7757
--- /dev/null
+++ b/sprint-mission-4/middlewares/auth.middleware.js
@@ -0,0 +1,55 @@
+import { verifyAccessToken } from '../lib/token.js';
+import prisma from '../lib/prisma.js';
+import { ACCESS_TOKEN_COOKIE_NAME } from '../lib/constants.js';
+
+export const authMiddleware = async (req, res, next) => {
+  try {
+    const accessToken = req.cookies[ACCESS_TOKEN_COOKIE_NAME];
+    if (!accessToken) {
+      throw new Error('No access token found');
+    }
+
+    const { userId } = verifyAccessToken(accessToken);
+    if (!userId) {
+      throw new Error('Invalid access token');
+    }
+
+    const user = await prisma.user.findUnique({
+      where: { id: userId },
+    });
+
+    if (!user) {
+      throw new Error('User not found');
+    }
+
+    req.user = user;
+    next();
+  } catch (error) {
+    res.status(401).json({ message: 'Unauthorized: ' + error.message });
+  }
+};
+
+export const softAuthMiddleware = async (req, res, next) => {
+  try {
+    const accessToken = req.cookies[ACCESS_TOKEN_COOKIE_NAME];
+    if (!accessToken) {
+      return next();
+    }
+
+    const { userId } = verifyAccessToken(accessToken);
+    if (!userId) {
+      return next();
+    }
+
+    const user = await prisma.user.findUnique({
+      where: { id: userId },
+    });
+
+    if (user) {
+      req.user = user;
+    }
+    next();
+  } catch (error) {
+    next();
+  }
+};
diff --git a/sprint-mission-4/package.json b/sprint-mission-4/package.json
new file mode 100644
index 00000000..b3e1813d
--- /dev/null
+++ b/sprint-mission-4/package.json
@@ -0,0 +1,18 @@
+{
+  "type": "module",
+  "scripts": {
+    "postinstall": "npx prisma generate && npx prisma migrate dev",
+    "start": "node app.js"
+  },
+  "dependencies": {
+    "@prisma/client": "^6.4.0",
+    "bcrypt": "^5.1.1",
+    "cookie-parser": "^1.4.7",
+    "cors": "^2.8.5",
+    "dotenv": "^16.4.7",
+    "express": "^4.21.2",
+    "helmet": "^8.1.0",
+    "jsonwebtoken": "^9.0.2",
+    "prisma": "^6.4.0"
+  }
+}
diff --git a/sprint-mission-4/prisma/migrations/20250220102901_/migration.sql b/sprint-mission-4/prisma/migrations/20250220102901_/migration.sql
new file mode 100644
index 00000000..294e2313
--- /dev/null
+++ b/sprint-mission-4/prisma/migrations/20250220102901_/migration.sql
@@ -0,0 +1,17 @@
+-- CreateTable
+CREATE TABLE "User" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "username" TEXT NOT NULL,
+    "password" TEXT NOT NULL
+);
+
+-- CreateTable
+CREATE TABLE "Post" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "content" TEXT NOT NULL,
+    "authorId" INTEGER NOT NULL,
+    CONSTRAINT "Post_authorId_fkey" FOREIGN KEY ("authorId") REFERENCES "User" ("id") ON DELETE RESTRICT ON UPDATE CASCADE
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "User_username_key" ON "User"("username");
diff --git a/sprint-mission-4/prisma/migrations/20251124112513_/migration.sql b/sprint-mission-4/prisma/migrations/20251124112513_/migration.sql
new file mode 100644
index 00000000..16aebf29
--- /dev/null
+++ b/sprint-mission-4/prisma/migrations/20251124112513_/migration.sql
@@ -0,0 +1,113 @@
+/*
+  Warnings:
+
+  - You are about to drop the `Post` table. If the table is not empty, all the data it contains will be lost.
+  - You are about to drop the column `username` on the `User` table. All the data in the column will be lost.
+  - Added the required column `email` to the `User` table without a default value. This is not possible if the table is not empty.
+  - Added the required column `nickname` to the `User` table without a default value. This is not possible if the table is not empty.
+  - Added the required column `updatedAt` to the `User` table without a default value. This is not possible if the table is not empty.
+
+*/
+-- DropTable
+PRAGMA foreign_keys=off;
+DROP TABLE "Post";
+PRAGMA foreign_keys=on;
+
+-- CreateTable
+CREATE TABLE "Product" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "title" TEXT NOT NULL,
+    "description" TEXT NOT NULL,
+    "price" INTEGER NOT NULL,
+    "image" TEXT,
+    "authorId" INTEGER NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "Product_authorId_fkey" FOREIGN KEY ("authorId") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateTable
+CREATE TABLE "Article" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "title" TEXT NOT NULL,
+    "content" TEXT NOT NULL,
+    "image" TEXT,
+    "authorId" INTEGER NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "Article_authorId_fkey" FOREIGN KEY ("authorId") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateTable
+CREATE TABLE "Comment" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "content" TEXT NOT NULL,
+    "authorId" INTEGER NOT NULL,
+    "productId" INTEGER,
+    "articleId" INTEGER,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "Comment_authorId_fkey" FOREIGN KEY ("authorId") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "Comment_productId_fkey" FOREIGN KEY ("productId") REFERENCES "Product" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "Comment_articleId_fkey" FOREIGN KEY ("articleId") REFERENCES "Article" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateTable
+CREATE TABLE "RefreshToken" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "token" TEXT NOT NULL,
+    "userId" INTEGER NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "RefreshToken_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateTable
+CREATE TABLE "_ProductLikes" (
+    "A" INTEGER NOT NULL,
+    "B" INTEGER NOT NULL,
+    CONSTRAINT "_ProductLikes_A_fkey" FOREIGN KEY ("A") REFERENCES "Product" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "_ProductLikes_B_fkey" FOREIGN KEY ("B") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateTable
+CREATE TABLE "_ArticleLikes" (
+    "A" INTEGER NOT NULL,
+    "B" INTEGER NOT NULL,
+    CONSTRAINT "_ArticleLikes_A_fkey" FOREIGN KEY ("A") REFERENCES "Article" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "_ArticleLikes_B_fkey" FOREIGN KEY ("B") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- RedefineTables
+PRAGMA defer_foreign_keys=ON;
+PRAGMA foreign_keys=OFF;
+CREATE TABLE "new_User" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "email" TEXT NOT NULL,
+    "nickname" TEXT NOT NULL,
+    "image" TEXT,
+    "password" TEXT NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL
+);
+INSERT INTO "new_User" ("id", "password") SELECT "id", "password" FROM "User";
+DROP TABLE "User";
+ALTER TABLE "new_User" RENAME TO "User";
+CREATE UNIQUE INDEX "User_email_key" ON "User"("email");
+PRAGMA foreign_keys=ON;
+PRAGMA defer_foreign_keys=OFF;
+
+-- CreateIndex
+CREATE UNIQUE INDEX "RefreshToken_token_key" ON "RefreshToken"("token");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "_ProductLikes_AB_unique" ON "_ProductLikes"("A", "B");
+
+-- CreateIndex
+CREATE INDEX "_ProductLikes_B_index" ON "_ProductLikes"("B");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "_ArticleLikes_AB_unique" ON "_ArticleLikes"("A", "B");
+
+-- CreateIndex
+CREATE INDEX "_ArticleLikes_B_index" ON "_ArticleLikes"("B");
diff --git a/sprint-mission-4/prisma/migrations/20251125043522_add_post_model/migration.sql b/sprint-mission-4/prisma/migrations/20251125043522_add_post_model/migration.sql
new file mode 100644
index 00000000..145b4723
--- /dev/null
+++ b/sprint-mission-4/prisma/migrations/20251125043522_add_post_model/migration.sql
@@ -0,0 +1,25 @@
+-- CreateTable
+CREATE TABLE "Post" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "title" TEXT NOT NULL,
+    "content" TEXT NOT NULL,
+    "image" TEXT,
+    "authorId" INTEGER NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "Post_authorId_fkey" FOREIGN KEY ("authorId") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateTable
+CREATE TABLE "_LikedPosts" (
+    "A" INTEGER NOT NULL,
+    "B" INTEGER NOT NULL,
+    CONSTRAINT "_LikedPosts_A_fkey" FOREIGN KEY ("A") REFERENCES "Post" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "_LikedPosts_B_fkey" FOREIGN KEY ("B") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "_LikedPosts_AB_unique" ON "_LikedPosts"("A", "B");
+
+-- CreateIndex
+CREATE INDEX "_LikedPosts_B_index" ON "_LikedPosts"("B");
diff --git a/sprint-mission-4/prisma/migrations/migration_lock.toml b/sprint-mission-4/prisma/migrations/migration_lock.toml
new file mode 100644
index 00000000..e1640d1f
--- /dev/null
+++ b/sprint-mission-4/prisma/migrations/migration_lock.toml
@@ -0,0 +1,3 @@
+# Please do not edit this file manually
+# It should be added in your version-control system (e.g., Git)
+provider = "sqlite"
\ No newline at end of file
diff --git a/sprint-mission-4/prisma/schema.prisma b/sprint-mission-4/prisma/schema.prisma
new file mode 100644
index 00000000..0f50403e
--- /dev/null
+++ b/sprint-mission-4/prisma/schema.prisma
@@ -0,0 +1,104 @@
+// prisma/schema.prisma
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "sqlite"
+  url      = "file:../dev.db"
+}
+
+model User {
+  id        Int      @id @default(autoincrement())
+  email     String   @unique
+  nickname  String
+  image     String?
+  password  String
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  products      Product[]
+  articles      Article[]
+  posts         Post[]         @relation("Posts")
+  comments      Comment[]
+  refreshTokens RefreshToken[]
+
+  // Likes (Implicit Many-to-Many)
+  likedProducts Product[] @relation("ProductLikes")
+  likedArticles Article[] @relation("ArticleLikes")
+  likedPosts    Post[]    @relation("LikedPosts")
+}
+
+model Product {
+  id           Int      @id @default(autoincrement())
+  title        String
+  description  String
+  price        Int
+  categoryName String? // 카테고리 이름 필드 추가
+  image        String?
+  authorId     Int
+  author       User     @relation(fields: [authorId], references: [id], onDelete: Cascade)
+  createdAt    DateTime @default(now())
+  updatedAt    DateTime @updatedAt
+
+  category Category? @relation(fields: [categoryName], references: [name])
+
+  comments Comment[]
+  likedBy  User[]    @relation("ProductLikes")
+}
+
+model Category {
+  name    String    @id @unique
+  product Product[]
+}
+
+model Article {
+  id        Int      @id @default(autoincrement())
+  title     String
+  content   String
+  image     String?
+  authorId  Int
+  author    User     @relation(fields: [authorId], references: [id], onDelete: Cascade)
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  comments Comment[]
+  likedBy  User[]    @relation("ArticleLikes")
+}
+
+model Post {
+  id        Int      @id @default(autoincrement())
+  title     String
+  content   String
+  image     String?
+  author    User     @relation("Posts", fields: [authorId], references: [id], onDelete: Cascade)
+  authorId  Int
+  likedBy   User[]   @relation("LikedPosts")
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  // 만약 Post에도 댓글 기능이 필요하다면 아래 관계를 추가합니다.
+  // comments    Comment[]
+}
+
+model Comment {
+  id        Int      @id @default(autoincrement())
+  content   String
+  authorId  Int
+  author    User     @relation(fields: [authorId], references: [id], onDelete: Cascade)
+  productId Int?
+  product   Product? @relation(fields: [productId], references: [id], onDelete: Cascade)
+  articleId Int?
+  article   Article? @relation(fields: [articleId], references: [id], onDelete: Cascade)
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+}
+
+model RefreshToken {
+  id        Int      @id @default(autoincrement())
+  token     String   @unique
+  userId    Int
+  user      User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+}
diff --git a/sprint-mission-4/routers/articles.router.js b/sprint-mission-4/routers/articles.router.js
new file mode 100644
index 00000000..bf1d0340
--- /dev/null
+++ b/sprint-mission-4/routers/articles.router.js
@@ -0,0 +1,252 @@
+import express from 'express';
+import prisma from '../lib/prisma.js';
+import {
+  authMiddleware,
+  softAuthMiddleware,
+} from '../middlewares/auth.middleware.js';
+
+const router = express.Router();
+
+// Create Article
+router.post('/', authMiddleware, async (req, res) => {
+  try {
+    const { title, content, image } = req.body;
+    const userId = req.user.id;
+
+    if (!title || !content) {
+      return res.status(400).json({ message: 'Missing required fields' });
+    }
+
+    const article = await prisma.article.create({
+      data: {
+        title,
+        content,
+        image,
+        authorId: userId,
+      },
+    });
+
+    res.status(201).json(article);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// List Articles
+router.get('/', softAuthMiddleware, async (req, res) => {
+  try {
+    const { page = 1, pageSize = 10, keyword } = req.query;
+    const skip = (page - 1) * pageSize;
+
+    const where = keyword
+      ? {
+          OR: [
+            { title: { contains: keyword } },
+            { content: { contains: keyword } },
+          ],
+        }
+      : {};
+
+    const articles = await prisma.article.findMany({
+      where,
+      skip,
+      take: parseInt(pageSize),
+      orderBy: { createdAt: 'desc' },
+      include: {
+        author: {
+          select: { id: true, nickname: true },
+        },
+        _count: {
+          select: { likedBy: true },
+        },
+      },
+    });
+
+    // Optimized approach for isLiked in list
+    let likedArticleIds = new Set();
+    if (req.user) {
+      const userLikes = await prisma.user.findUnique({
+        where: { id: req.user.id },
+        select: { likedArticles: { select: { id: true } } },
+      });
+      if (userLikes) {
+        likedArticleIds = new Set(userLikes.likedArticles.map((a) => a.id));
+      }
+    }
+
+    const result = articles.map((article) => ({
+      ...article,
+      likeCount: article._count.likedBy,
+      isLiked: likedArticleIds.has(article.id),
+    }));
+
+    res.json(result);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Get Article Detail
+router.get('/:id', softAuthMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const articleId = parseInt(id);
+
+    const article = await prisma.article.findUnique({
+      where: { id: articleId },
+      include: {
+        author: {
+          select: { id: true, nickname: true, image: true },
+        },
+        _count: {
+          select: { likedBy: true },
+        },
+      },
+    });
+
+    if (!article) {
+      return res.status(404).json({ message: 'Article not found' });
+    }
+
+    let isLiked = false;
+    if (req.user) {
+      const likeCheck = await prisma.article.findFirst({
+        where: {
+          id: articleId,
+          likedBy: {
+            some: { id: req.user.id },
+          },
+        },
+      });
+      isLiked = !!likeCheck;
+    }
+
+    res.json({
+      ...article,
+      likeCount: article._count.likedBy,
+      isLiked,
+    });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Update Article
+router.patch('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const { title, content, image } = req.body;
+    const userId = req.user.id;
+    const articleId = parseInt(id);
+
+    const article = await prisma.article.findUnique({
+      where: { id: articleId },
+    });
+    if (!article) {
+      return res.status(404).json({ message: 'Article not found' });
+    }
+
+    if (article.authorId !== userId) {
+      return res.status(403).json({ message: 'Forbidden' });
+    }
+
+    const updatedArticle = await prisma.article.update({
+      where: { id: articleId },
+      data: {
+        title,
+        content,
+        image,
+      },
+    });
+
+    res.json(updatedArticle);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Delete Article
+router.delete('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const articleId = parseInt(id);
+
+    const article = await prisma.article.findUnique({
+      where: { id: articleId },
+    });
+    if (!article) {
+      return res.status(404).json({ message: 'Article not found' });
+    }
+
+    if (article.authorId !== userId) {
+      return res.status(403).json({ message: 'Forbidden' });
+    }
+
+    await prisma.article.delete({ where: { id: articleId } });
+
+    res.json({ message: 'Article deleted successfully' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Toggle Like
+router.post('/:id/likes', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const articleId = parseInt(id);
+
+    const article = await prisma.article.findUnique({
+      where: { id: articleId },
+    });
+    if (!article) {
+      return res.status(404).json({ message: 'Article not found' });
+    }
+
+    // Check if already liked
+    const isLiked = await prisma.article.findFirst({
+      where: {
+        id: articleId,
+        likedBy: {
+          some: { id: userId },
+        },
+      },
+    });
+
+    if (isLiked) {
+      // Unlike
+      await prisma.article.update({
+        where: { id: articleId },
+        data: {
+          likedBy: {
+            disconnect: { id: userId },
+          },
+        },
+      });
+      res.json({ message: 'Unliked', isLiked: false });
+    } else {
+      // Like
+      await prisma.article.update({
+        where: { id: articleId },
+        data: {
+          likedBy: {
+            connect: { id: userId },
+          },
+        },
+      });
+      res.json({ message: 'Liked', isLiked: true });
+    }
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+export default router;
diff --git a/sprint-mission-4/routers/auth.router.js b/sprint-mission-4/routers/auth.router.js
new file mode 100644
index 00000000..e79754e5
--- /dev/null
+++ b/sprint-mission-4/routers/auth.router.js
@@ -0,0 +1,173 @@
+import express from 'express';
+import bcrypt from 'bcrypt';
+import prisma from '../lib/prisma.js';
+import { generateTokens, verifyRefreshToken } from '../lib/token.js';
+import {
+  ACCESS_TOKEN_COOKIE_NAME,
+  REFRESH_TOKEN_COOKIE_NAME,
+  NODE_ENV,
+} from '../lib/constants.js';
+
+const router = express.Router();
+
+// Signup
+router.post('/signup', async (req, res) => {
+  try {
+    const { email, nickname, password, image } = req.body;
+
+    if (!email || !nickname || !password) {
+      return res.status(400).json({ message: 'Missing required fields' });
+    }
+
+    const existingUser = await prisma.user.findUnique({ where: { email } });
+    if (existingUser) {
+      return res.status(409).json({ message: 'Email already exists' });
+    }
+
+    const hashedPassword = await bcrypt.hash(password, 12);
+
+    const user = await prisma.user.create({
+      data: {
+        email,
+        nickname,
+        password: hashedPassword,
+        image,
+      },
+    });
+
+    // Don't return password
+    const { password: _, ...userWithoutPassword } = user;
+
+    res.status(201).json(userWithoutPassword);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Login
+router.post('/login', async (req, res) => {
+  try {
+    // 1. 요청 본문(body)에서 email과 password를 가져옵니다.
+    const { email, password } = req.body;
+
+    // 2. 유효성 검사: email 또는 password가 없는 경우 에러 처리
+    if (!email || !password) {
+      return res
+        .status(400)
+        .json({ message: '이메일과 비밀번호는 필수 입력 항목입니다.' });
+    }
+
+    // 3. email로 사용자를 찾습니다.
+    const user = await prisma.user.findUnique({
+      where: { email },
+    });
+
+    if (!user) {
+      return res
+        .status(401)
+        .json({ message: '인증 정보가 유효하지 않습니다.' });
+    }
+
+    // 4. 비밀번호를 비교합니다.
+    const isPasswordValid = await bcrypt.compare(password, user.password);
+    if (!isPasswordValid) {
+      return res
+        .status(401)
+        .json({ message: '인증 정보가 유효하지 않습니다.' });
+    }
+
+    // 5. 토큰을 생성합니다.
+    const { accessToken, refreshToken } = generateTokens(user.id);
+
+    // 6. Refresh Token을 데이터베이스에 저장합니다.
+    await prisma.refreshToken.create({
+      data: {
+        token: refreshToken,
+        userId: user.id,
+      },
+    });
+
+    // 7. 토큰을 쿠키에 담아 응답합니다.
+    const cookieOptions = {
+      httpOnly: true,
+      secure: NODE_ENV === 'production',
+      sameSite: 'lax',
+    };
+    res.cookie(ACCESS_TOKEN_COOKIE_NAME, accessToken, cookieOptions);
+    res.cookie(REFRESH_TOKEN_COOKIE_NAME, refreshToken, cookieOptions);
+
+    res.json({ message: '로그인에 성공했습니다.' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Refresh Token
+router.post('/refresh', async (req, res) => {
+  try {
+    const refreshToken = req.cookies[REFRESH_TOKEN_COOKIE_NAME];
+    if (!refreshToken) {
+      return res.status(401).json({ message: 'No refresh token provided' });
+    }
+
+    const { userId } = verifyRefreshToken(refreshToken);
+
+    // Check if refresh token exists in DB
+    const savedToken = await prisma.refreshToken.findUnique({
+      where: { token: refreshToken },
+    });
+
+    if (!savedToken) {
+      return res.status(401).json({ message: 'Invalid refresh token' });
+    }
+
+    // Generate new tokens
+    const { accessToken, refreshToken: newRefreshToken } =
+      generateTokens(userId);
+
+    // Rotate refresh token (delete old, create new)
+    // Transaction to ensure atomicity
+    await prisma.$transaction([
+      prisma.refreshToken.delete({ where: { token: refreshToken } }),
+      prisma.refreshToken.create({
+        data: {
+          token: newRefreshToken,
+          userId,
+        },
+      }),
+    ]);
+
+    res.cookie(ACCESS_TOKEN_COOKIE_NAME, accessToken, { httpOnly: true });
+    res.cookie(REFRESH_TOKEN_COOKIE_NAME, newRefreshToken, { httpOnly: true });
+
+    res.json({ message: 'Token refreshed' });
+  } catch (error) {
+    console.error(error);
+    res.status(401).json({ message: 'Invalid or expired refresh token' });
+  }
+});
+
+// Logout
+router.post('/logout', async (req, res) => {
+  try {
+    const refreshToken = req.cookies[REFRESH_TOKEN_COOKIE_NAME];
+    if (refreshToken) {
+      // Delete the token from DB only if it exists
+      await prisma.refreshToken
+        .delete({ where: { token: refreshToken } })
+        .catch(() => {}); // Ignore errors if token is not found
+    }
+
+    res.clearCookie(ACCESS_TOKEN_COOKIE_NAME);
+    res.clearCookie(REFRESH_TOKEN_COOKIE_NAME);
+
+    res.json({ message: 'Logged out successfully' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+export default router;
diff --git a/sprint-mission-4/routers/comments.router.js b/sprint-mission-4/routers/comments.router.js
new file mode 100644
index 00000000..45f3a8aa
--- /dev/null
+++ b/sprint-mission-4/routers/comments.router.js
@@ -0,0 +1,161 @@
+import express from 'express';
+import prisma from '../lib/prisma.js';
+import { authMiddleware } from '../middlewares/auth.middleware.js';
+
+const router = express.Router();
+
+// Create Comment
+router.post('/', authMiddleware, async (req, res) => {
+  try {
+    const { content, productId, articleId } = req.body;
+    const userId = req.user.id;
+
+    if (!content) {
+      return res.status(400).json({ message: 'Content is required' });
+    }
+
+    if (!productId && !articleId) {
+      return res
+        .status(400)
+        .json({ message: 'ProductId or ArticleId is required' });
+    }
+
+    if (productId && articleId) {
+      return res
+        .status(400)
+        .json({ message: 'Cannot comment on both Product and Article' });
+    }
+
+    // Check if target exists
+    if (productId) {
+      const product = await prisma.product.findUnique({
+        where: { id: parseInt(productId) },
+      });
+      if (!product) {
+        return res.status(404).json({ message: 'Product not found' });
+      }
+    }
+
+    if (articleId) {
+      const article = await prisma.article.findUnique({
+        where: { id: parseInt(articleId) },
+      });
+      if (!article) {
+        return res.status(404).json({ message: 'Article not found' });
+      }
+    }
+
+    const comment = await prisma.comment.create({
+      data: {
+        content,
+        authorId: userId,
+        productId: productId ? parseInt(productId) : null,
+        articleId: articleId ? parseInt(articleId) : null,
+      },
+    });
+
+    res.status(201).json(comment);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// List Comments
+router.get('/', async (req, res) => {
+  try {
+    const { productId, articleId, page = 1, pageSize = 10 } = req.query;
+    const skip = (page - 1) * pageSize;
+
+    if (!productId && !articleId) {
+      return res
+        .status(400)
+        .json({ message: 'ProductId or ArticleId is required' });
+    }
+
+    const where = {};
+    if (productId) where.productId = parseInt(productId);
+    if (articleId) where.articleId = parseInt(articleId);
+
+    const comments = await prisma.comment.findMany({
+      where,
+      skip,
+      take: parseInt(pageSize),
+      orderBy: { createdAt: 'desc' },
+      include: {
+        author: {
+          select: { id: true, nickname: true, image: true },
+        },
+      },
+    });
+
+    res.json(comments);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Update Comment
+router.patch('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const { content } = req.body;
+    const userId = req.user.id;
+    const commentId = parseInt(id);
+
+    if (!content) {
+      return res.status(400).json({ message: 'Content is required' });
+    }
+
+    const comment = await prisma.comment.findUnique({
+      where: { id: commentId },
+    });
+    if (!comment) {
+      return res.status(404).json({ message: 'Comment not found' });
+    }
+
+    if (comment.authorId !== userId) {
+      return res.status(403).json({ message: 'Forbidden' });
+    }
+
+    const updatedComment = await prisma.comment.update({
+      where: { id: commentId },
+      data: { content },
+    });
+
+    res.json(updatedComment);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Delete Comment
+router.delete('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const commentId = parseInt(id);
+
+    const comment = await prisma.comment.findUnique({
+      where: { id: commentId },
+    });
+    if (!comment) {
+      return res.status(404).json({ message: 'Comment not found' });
+    }
+
+    if (comment.authorId !== userId) {
+      return res.status(403).json({ message: 'Forbidden' });
+    }
+
+    await prisma.comment.delete({ where: { id: commentId } });
+
+    res.json({ message: 'Comment deleted successfully' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+export default router;
diff --git a/sprint-mission-4/routers/index.js b/sprint-mission-4/routers/index.js
new file mode 100644
index 00000000..b8a62e96
--- /dev/null
+++ b/sprint-mission-4/routers/index.js
@@ -0,0 +1,10 @@
+import express from 'express';
+import authRouter from './authRouter.js';
+import postRouter from './postRouter.js';
+
+const router = express.Router();
+
+router.use(authRouter);
+router.use(postRouter);
+
+export default router;
\ No newline at end of file
diff --git a/sprint-mission-4/routers/posts.router.js b/sprint-mission-4/routers/posts.router.js
new file mode 100644
index 00000000..2f51101a
--- /dev/null
+++ b/sprint-mission-4/routers/posts.router.js
@@ -0,0 +1,247 @@
+import express from 'express';
+import prisma from '../lib/prisma.js';
+import {
+  authMiddleware,
+  softAuthMiddleware,
+} from '../middlewares/auth.middleware.js';
+
+const router = express.Router();
+
+// Create Post
+router.post('/', authMiddleware, async (req, res) => {
+  try {
+    const { title, content, image } = req.body;
+    const userId = req.user.id;
+
+    if (!title || !content) {
+      return res.status(400).json({ message: '제목과 내용은 필수입니다.' });
+    }
+
+    // Prisma 스키마에 'Post' 모델이 있다고 가정합니다.
+    const post = await prisma.post.create({
+      data: {
+        title,
+        content,
+        image,
+        authorId: userId,
+      },
+    });
+
+    res.status(201).json(post);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// List Posts
+router.get('/', softAuthMiddleware, async (req, res) => {
+  try {
+    const { page = 1, pageSize = 10, keyword } = req.query;
+    const skip = (page - 1) * pageSize;
+
+    const where = keyword
+      ? {
+          OR: [
+            { title: { contains: keyword } },
+            { content: { contains: keyword } },
+          ],
+        }
+      : {};
+
+    const posts = await prisma.post.findMany({
+      where,
+      skip,
+      take: parseInt(pageSize),
+      orderBy: { createdAt: 'desc' },
+      include: {
+        author: {
+          select: { id: true, nickname: true },
+        },
+        _count: {
+          select: { likedBy: true },
+        },
+      },
+    });
+
+    let likedPostIds = new Set();
+    if (req.user) {
+      const userLikes = await prisma.user.findUnique({
+        where: { id: req.user.id },
+        select: { likedPosts: { select: { id: true } } }, // 'likedPosts' 관계가 필요합니다.
+      });
+      if (userLikes) {
+        likedPostIds = new Set(userLikes.likedPosts.map((p) => p.id));
+      }
+    }
+
+    const result = posts.map((post) => ({
+      ...post,
+      likeCount: post._count.likedBy,
+      isLiked: likedPostIds.has(post.id),
+    }));
+
+    res.json(result);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Get Post Detail
+router.get('/:id', softAuthMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const postId = parseInt(id);
+
+    const post = await prisma.post.findUnique({
+      where: { id: postId },
+      include: {
+        author: {
+          select: { id: true, nickname: true, image: true },
+        },
+        _count: {
+          select: { likedBy: true },
+        },
+      },
+    });
+
+    if (!post) {
+      return res.status(404).json({ message: '게시물을 찾을 수 없습니다.' });
+    }
+
+    let isLiked = false;
+    if (req.user) {
+      const likeCheck = await prisma.post.findFirst({
+        where: {
+          id: postId,
+          likedBy: {
+            some: { id: req.user.id },
+          },
+        },
+      });
+      isLiked = !!likeCheck;
+    }
+
+    res.json({
+      ...post,
+      likeCount: post._count.likedBy,
+      isLiked,
+    });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Update Post
+router.patch('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const { title, content, image } = req.body;
+    const userId = req.user.id;
+    const postId = parseInt(id);
+
+    const post = await prisma.post.findUnique({
+      where: { id: postId },
+    });
+    if (!post) {
+      return res.status(404).json({ message: '게시물을 찾을 수 없습니다.' });
+    }
+
+    if (post.authorId !== userId) {
+      return res.status(403).json({ message: '수정 권한이 없습니다.' });
+    }
+
+    const updatedPost = await prisma.post.update({
+      where: { id: postId },
+      data: {
+        title,
+        content,
+        image,
+      },
+    });
+
+    res.json(updatedPost);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Delete Post
+router.delete('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const postId = parseInt(id);
+
+    const post = await prisma.post.findUnique({
+      where: { id: postId },
+    });
+    if (!post) {
+      return res.status(404).json({ message: '게시물을 찾을 수 없습니다.' });
+    }
+
+    if (post.authorId !== userId) {
+      return res.status(403).json({ message: '삭제 권한이 없습니다.' });
+    }
+
+    await prisma.post.delete({ where: { id: postId } });
+
+    res.json({ message: '게시물이 삭제되었습니다.' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Toggle Like
+router.post('/:id/likes', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const postId = parseInt(id);
+
+    const post = await prisma.post.findUnique({
+      where: { id: postId },
+    });
+    if (!post) {
+      return res.status(404).json({ message: '게시물을 찾을 수 없습니다.' });
+    }
+
+    const isLiked = await prisma.post.findFirst({
+      where: {
+        id: postId,
+        likedBy: {
+          some: { id: userId },
+        },
+      },
+    });
+
+    if (isLiked) {
+      // Unlike
+      await prisma.post.update({
+        where: { id: postId },
+        data: {
+          likedBy: { disconnect: { id: userId } },
+        },
+      });
+      res.json({ message: '좋아요를 취소했습니다.', isLiked: false });
+    } else {
+      // Like
+      await prisma.post.update({
+        where: { id: postId },
+        data: {
+          likedBy: { connect: { id: userId } },
+        },
+      });
+      res.json({ message: '좋아요를 눌렀습니다.', isLiked: true });
+    }
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+export default router;
diff --git a/sprint-mission-4/routers/products.router.js b/sprint-mission-4/routers/products.router.js
new file mode 100644
index 00000000..15ab30fb
--- /dev/null
+++ b/sprint-mission-4/routers/products.router.js
@@ -0,0 +1,271 @@
+import express from 'express';
+import prisma from '../lib/prisma.js';
+import {
+  authMiddleware,
+  softAuthMiddleware,
+} from '../middlewares/auth.middleware.js';
+
+const router = express.Router();
+
+// Create Product
+router.post('/', authMiddleware, async (req, res) => {
+  try {
+    const { title, description, price, image } = req.body;
+    const userId = req.user.id;
+
+    if (!title || !description || !price) {
+      return res.status(400).json({ message: 'Missing required fields' });
+    }
+
+    const product = await prisma.product.create({
+      data: {
+        title,
+        description,
+        price: parseInt(price),
+        image,
+        authorId: userId,
+      },
+    });
+
+    res.status(201).json(product);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// List Products
+router.get('/', softAuthMiddleware, async (req, res) => {
+  try {
+    const { page = 1, pageSize = 10, keyword } = req.query;
+    const skip = (page - 1) * pageSize;
+
+    const where = keyword
+      ? {
+          OR: [
+            { title: { contains: keyword } },
+            { description: { contains: keyword } },
+          ],
+        }
+      : {};
+
+    const products = await prisma.product.findMany({
+      where,
+      skip,
+      take: parseInt(pageSize),
+      orderBy: { createdAt: 'desc' },
+      include: {
+        author: {
+          select: { id: true, nickname: true },
+        },
+        _count: {
+          select: { likedBy: true },
+        },
+      },
+    });
+
+    const productsWithLike = products.map((product) => {
+      let isLiked = false;
+      if (req.user) {
+        // This is inefficient for many products.
+        // Better to fetch liked IDs separately or use a subquery if possible.
+        // For simplicity/Prisma limitations, we might need to fetch user's liked products IDs first.
+        // Or include `likedBy` with `where` clause in the main query?
+        // Prisma `include` with `where` on relation is possible.
+      }
+      return {
+        ...product,
+        likeCount: product._count.likedBy,
+        isLiked, // We'll fix this below
+      };
+    });
+
+    // Optimized approach for isLiked in list:
+    // Fetch user's liked product IDs if logged in
+    let likedProductIds = new Set();
+    if (req.user) {
+      const userLikes = await prisma.user.findUnique({
+        where: { id: req.user.id },
+        select: { likedProducts: { select: { id: true } } },
+      });
+      if (userLikes) {
+        likedProductIds = new Set(userLikes.likedProducts.map((p) => p.id));
+      }
+    }
+
+    const result = products.map((product) => ({
+      ...product,
+      likeCount: product._count.likedBy,
+      isLiked: likedProductIds.has(product.id),
+    }));
+
+    res.json(result);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Get Product Detail
+router.get('/:id', softAuthMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const productId = parseInt(id);
+
+    const product = await prisma.product.findUnique({
+      where: { id: productId },
+      include: {
+        author: {
+          select: { id: true, nickname: true, image: true },
+        },
+        _count: {
+          select: { likedBy: true },
+        },
+      },
+    });
+
+    if (!product) {
+      return res.status(404).json({ message: 'Product not found' });
+    }
+
+    let isLiked = false;
+    if (req.user) {
+      const likeCheck = await prisma.product.findFirst({
+        where: {
+          id: productId,
+          likedBy: {
+            some: { id: req.user.id },
+          },
+        },
+      });
+      isLiked = !!likeCheck;
+    }
+
+    res.json({
+      ...product,
+      likeCount: product._count.likedBy,
+      isLiked,
+    });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Update Product
+router.patch('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const { title, description, price, image } = req.body;
+    const userId = req.user.id;
+    const productId = parseInt(id);
+
+    const product = await prisma.product.findUnique({
+      where: { id: productId },
+    });
+    if (!product) {
+      return res.status(404).json({ message: 'Product not found' });
+    }
+
+    if (product.authorId !== userId) {
+      return res.status(403).json({ message: 'Forbidden' });
+    }
+
+    const updatedProduct = await prisma.product.update({
+      where: { id: productId },
+      data: {
+        title,
+        description,
+        price: price ? parseInt(price) : undefined,
+        image,
+      },
+    });
+
+    res.json(updatedProduct);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Delete Product
+router.delete('/:id', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const productId = parseInt(id);
+
+    const product = await prisma.product.findUnique({
+      where: { id: productId },
+    });
+    if (!product) {
+      return res.status(404).json({ message: 'Product not found' });
+    }
+
+    if (product.authorId !== userId) {
+      return res.status(403).json({ message: 'Forbidden' });
+    }
+
+    await prisma.product.delete({ where: { id: productId } });
+
+    res.json({ message: 'Product deleted successfully' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Toggle Like
+router.post('/:id/likes', authMiddleware, async (req, res) => {
+  try {
+    const { id } = req.params;
+    const userId = req.user.id;
+    const productId = parseInt(id);
+
+    const product = await prisma.product.findUnique({
+      where: { id: productId },
+    });
+    if (!product) {
+      return res.status(404).json({ message: 'Product not found' });
+    }
+
+    // Check if already liked
+    const isLiked = await prisma.product.findFirst({
+      where: {
+        id: productId,
+        likedBy: {
+          some: { id: userId },
+        },
+      },
+    });
+
+    if (isLiked) {
+      // Unlike
+      await prisma.product.update({
+        where: { id: productId },
+        data: {
+          likedBy: {
+            disconnect: { id: userId },
+          },
+        },
+      });
+      res.json({ message: 'Unliked', isLiked: false });
+    } else {
+      // Like
+      await prisma.product.update({
+        where: { id: productId },
+        data: {
+          likedBy: {
+            connect: { id: userId },
+          },
+        },
+      });
+      res.json({ message: 'Liked', isLiked: true });
+    }
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+export default router;
diff --git a/sprint-mission-4/routers/users.router.js b/sprint-mission-4/routers/users.router.js
new file mode 100644
index 00000000..ab411bfa
--- /dev/null
+++ b/sprint-mission-4/routers/users.router.js
@@ -0,0 +1,144 @@
+import express from 'express';
+import bcrypt from 'bcrypt';
+import prisma from '../lib/prisma.js';
+import { authMiddleware } from '../middlewares/auth.middleware.js';
+
+const router = express.Router();
+
+// Helper function to exclude password from user object
+const excludePassword = (user) => {
+  const { password, ...userWithoutPassword } = user;
+  return userWithoutPassword;
+};
+
+// Get My Info
+router.get('/me', authMiddleware, async (req, res) => {
+  try {
+    const user = req.user;
+    const userWithoutPassword = excludePassword(user);
+    res.json(userWithoutPassword);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Update My Info
+router.patch('/me', authMiddleware, async (req, res) => {
+  try {
+    const { nickname, image } = req.body;
+    const userId = req.user.id;
+
+    if (nickname === undefined && image === undefined) {
+      return res.status(400).json({
+        message: 'At least one field (nickname or image) is required',
+      });
+    }
+
+    const updatedUser = await prisma.user.update({
+      where: { id: userId },
+      data: {
+        nickname,
+        image,
+      },
+    });
+
+    const userWithoutPassword = excludePassword(updatedUser);
+    res.json(userWithoutPassword);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Change Password
+router.patch('/me/password', authMiddleware, async (req, res) => {
+  try {
+    const { currentPassword, newPassword } = req.body;
+    const userId = req.user.id;
+
+    if (!currentPassword || !newPassword) {
+      return res.status(400).json({ message: 'Missing required fields' });
+    }
+
+    if (newPassword.length < 6) {
+      return res
+        .status(400)
+        .json({ message: 'New password must be at least 6 characters long' });
+    }
+
+    if (currentPassword === newPassword) {
+      return res
+        .status(400)
+        .json({
+          message: 'New password cannot be the same as current password',
+        });
+    }
+
+    const user = await prisma.user.findUnique({ where: { id: userId } });
+    if (!user) {
+      return res.status(404).json({ message: 'User not found' });
+    }
+
+    const isPasswordValid = await bcrypt.compare(
+      currentPassword,
+      user.password
+    );
+
+    if (!isPasswordValid) {
+      return res.status(401).json({ message: 'Invalid current password' });
+    }
+
+    const hashedNewPassword = await bcrypt.hash(newPassword, 12);
+
+    await prisma.user.update({
+      where: { id: userId },
+      data: {
+        password: hashedNewPassword,
+      },
+    });
+
+    res.json({ message: 'Password updated successfully' });
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Get My Products
+router.get('/me/products', authMiddleware, async (req, res) => {
+  try {
+    const userId = req.user.id;
+    const products = await prisma.product.findMany({
+      where: { authorId: userId },
+      orderBy: { createdAt: 'desc' },
+    });
+    res.json(products);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+// Get My Liked Products
+router.get('/me/likes', authMiddleware, async (req, res) => {
+  try {
+    const userId = req.user.id;
+    // Using implicit many-to-many relation
+    const userWithLikes = await prisma.user.findUnique({
+      where: { id: userId },
+      include: {
+        likedProducts: {
+          orderBy: { createdAt: 'desc' },
+        },
+      },
+    });
+
+    res.json(userWithLikes.likedProducts);
+  } catch (error) {
+    console.error(error);
+    res.status(500).json({ message: 'Internal Server Error' });
+  }
+});
+
+export default router;