diff --git a/src/main/java/com/sayup/SayUp/controller/AuthController.java b/src/main/java/com/sayup/SayUp/controller/AuthController.java
index 583f4ae..2439ab0 100644
--- a/src/main/java/com/sayup/SayUp/controller/AuthController.java
+++ b/src/main/java/com/sayup/SayUp/controller/AuthController.java
@@ -9,8 +9,6 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
-import java.util.Map;
-
 @RestController
 @RequestMapping("/api/auth")
 @AllArgsConstructor
diff --git a/src/main/java/com/sayup/SayUp/controller/ChatRoomController.java b/src/main/java/com/sayup/SayUp/controller/ChatRoomController.java
new file mode 100644
index 0000000..f7db16a
--- /dev/null
+++ b/src/main/java/com/sayup/SayUp/controller/ChatRoomController.java
@@ -0,0 +1,22 @@
+package com.sayup.SayUp.controller;
+
+import com.sayup.SayUp.entity.ChatRoom;
+import com.sayup.SayUp.service.ChatRoomService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/chat-rooms")
+@RequiredArgsConstructor
+public class ChatRoomController {
+
+    private final ChatRoomService chatRoomService;
+
+    @PostMapping("/enter")
+    public ChatRoom enterRoom(
+            @RequestParam("currentUserId") Long currentUserId,
+            @RequestParam("friendUserId") Long friendUserId
+    ) throws Exception {
+        return chatRoomService.createOrEnterRoom(currentUserId, friendUserId);
+    }
+}
diff --git a/src/main/java/com/sayup/SayUp/controller/FriendshipController.java b/src/main/java/com/sayup/SayUp/controller/FriendshipController.java
index 8f0a2ff..9d4a8de 100644
--- a/src/main/java/com/sayup/SayUp/controller/FriendshipController.java
+++ b/src/main/java/com/sayup/SayUp/controller/FriendshipController.java
@@ -22,7 +22,7 @@ public class FriendshipController {
     private final FriendshipService friendshipService;
 
     @PostMapping("/request/{addresseeId}")
-    public ResponseEntity<?> sendFriendRequest(@AuthenticationPrincipal UserDetails userDetails, @PathVariable Integer addresseeId) {
+    public ResponseEntity<?> sendFriendRequest(@AuthenticationPrincipal UserDetails userDetails, @PathVariable Long addresseeId) {
         if (userDetails == null) {
             return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body("User not authenticated");
         }
diff --git a/src/main/java/com/sayup/SayUp/dto/AuthRequestDTO.java b/src/main/java/com/sayup/SayUp/dto/AuthRequestDTO.java
index 4786418..6ee9e7c 100644
--- a/src/main/java/com/sayup/SayUp/dto/AuthRequestDTO.java
+++ b/src/main/java/com/sayup/SayUp/dto/AuthRequestDTO.java
@@ -1,13 +1,15 @@
 package com.sayup.SayUp.dto;
 
-import jakarta.validation.constraints.Email;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.Pattern;
 import jakarta.validation.constraints.Size;
-import lombok.*;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
 
 @Data
 @AllArgsConstructor
+@NoArgsConstructor
 public class AuthRequestDTO {
     @NotBlank(message = "Email cannot be blank")
     @Pattern(regexp="^[0-9a-zA-Z]([-_.]?[0-9a-zA-Z])*@[0-9a-zA-Z]([-_.]?[0-9a-zA-Z])+[.][a-zA-Z]{2,3}$", message="이메일 주소 양식을 확인해주세요")
diff --git a/src/main/java/com/sayup/SayUp/dto/AuthResponseDTO.java b/src/main/java/com/sayup/SayUp/dto/AuthResponseDTO.java
index 17182a0..60b3189 100644
--- a/src/main/java/com/sayup/SayUp/dto/AuthResponseDTO.java
+++ b/src/main/java/com/sayup/SayUp/dto/AuthResponseDTO.java
@@ -7,4 +7,5 @@
 public class AuthResponseDTO {
     private final String token;
     private final String email;
+    private final String id;
 }
diff --git a/src/main/java/com/sayup/SayUp/entity/ChatRoom.java b/src/main/java/com/sayup/SayUp/entity/ChatRoom.java
new file mode 100644
index 0000000..d31f31b
--- /dev/null
+++ b/src/main/java/com/sayup/SayUp/entity/ChatRoom.java
@@ -0,0 +1,35 @@
+package com.sayup.SayUp.entity;
+
+import jakarta.persistence.*;
+import lombok.*;
+
+import java.time.LocalDateTime;
+import java.util.*;
+
+@Entity
+@Table(name = "ChatRoom")
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class ChatRoom {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    // 채팅방에 참여하는 유저들
+    @ManyToMany
+    @JoinTable(
+            name = "ChatRoom_Users",
+            joinColumns = @JoinColumn(name = "chatroom_id"),
+            inverseJoinColumns = @JoinColumn(name = "user_id")
+    )
+    private List<User> participants = new ArrayList<>();
+
+    @Lob
+    private String metadata; // TTS 벡터 등 JSON 문자열로 저장
+
+    private LocalDateTime createdAt = LocalDateTime.now();
+}
diff --git a/src/main/java/com/sayup/SayUp/kakao/controller/KakaoCallbackController.java b/src/main/java/com/sayup/SayUp/kakao/controller/KakaoCallbackController.java
index 9fe0a06..ee086de 100644
--- a/src/main/java/com/sayup/SayUp/kakao/controller/KakaoCallbackController.java
+++ b/src/main/java/com/sayup/SayUp/kakao/controller/KakaoCallbackController.java
@@ -1,6 +1,7 @@
 package com.sayup.SayUp.kakao.controller;
 
 import com.sayup.SayUp.dto.AuthResponseDTO;
+import com.sayup.SayUp.entity.User;
 import com.sayup.SayUp.kakao.dto.KakaoUserInfoResponseDto;
 import com.sayup.SayUp.kakao.service.KakaoService;
 import com.sayup.SayUp.security.JwtTokenProvider;
@@ -26,16 +27,18 @@ public class KakaoCallbackController {
     @GetMapping("/callback")
     public ResponseEntity<AuthResponseDTO> callback(@RequestParam("code") String code) {
         String accessToken = kakaoService.getAccessTokenFromKakao(code);
+
         KakaoUserInfoResponseDto userInfo = kakaoService.getUserInfo(accessToken);
 
         if (userInfo.getKakaoAccount() == null || userInfo.getKakaoAccount().getEmail() == null) {
-            return ResponseEntity.badRequest().body(new AuthResponseDTO(null, null));
+            return ResponseEntity.badRequest().body(new AuthResponseDTO(null, null, null));
         }
 
         String email = userInfo.getKakaoAccount().getEmail();
-        authService.loadOrCreateUser(email);
+        User user = authService.loadOrCreateUser(email);
         String jwt = jwtTokenProvider.createTokenFromEmail(email);
 
-        return ResponseEntity.ok(new AuthResponseDTO(jwt, email));
+        AuthResponseDTO response = new AuthResponseDTO(jwt, email, String.valueOf(user.getUserId()));
+        return ResponseEntity.ok(response);
     }
 }
diff --git a/src/main/java/com/sayup/SayUp/repository/ChatRoomRepository.java b/src/main/java/com/sayup/SayUp/repository/ChatRoomRepository.java
new file mode 100644
index 0000000..2beaa09
--- /dev/null
+++ b/src/main/java/com/sayup/SayUp/repository/ChatRoomRepository.java
@@ -0,0 +1,17 @@
+package com.sayup.SayUp.repository;
+
+import com.sayup.SayUp.entity.ChatRoom;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+
+import java.util.Optional;
+
+public interface ChatRoomRepository extends JpaRepository<ChatRoom, Long> {
+
+    // 두 명의 유저가 모두 참여하고 있는 방을 찾기
+    @Query("SELECT r FROM ChatRoom r JOIN r.participants p1 JOIN r.participants p2 WHERE p1.userId = :userId1 AND p2.userId = :userId2")
+    Optional<ChatRoom> findByUserIds(@Param("userId1") Long userId1,
+                                     @Param("userId2") Long userId2
+    );
+}
diff --git a/src/main/java/com/sayup/SayUp/repository/UserRepository.java b/src/main/java/com/sayup/SayUp/repository/UserRepository.java
index e67b4d8..01ccbc7 100644
--- a/src/main/java/com/sayup/SayUp/repository/UserRepository.java
+++ b/src/main/java/com/sayup/SayUp/repository/UserRepository.java
@@ -10,7 +10,7 @@
 import java.util.Optional;
 
 @Repository
-public interface UserRepository extends JpaRepository<User, Integer> {
+public interface UserRepository extends JpaRepository<User, Long> {
     Optional<User> findByEmail(String email);
 
     // email 또는 username 중 하나라도 일치하는 유저 조회
diff --git a/src/main/java/com/sayup/SayUp/service/AuthService.java b/src/main/java/com/sayup/SayUp/service/AuthService.java
index 46094cd..2cf9677 100644
--- a/src/main/java/com/sayup/SayUp/service/AuthService.java
+++ b/src/main/java/com/sayup/SayUp/service/AuthService.java
@@ -67,12 +67,17 @@ public void register(AuthRequestDTO authRequestDTO) {
     }
 
     // 카카오 로그인 시 사용자 자동 등록
-    public void loadOrCreateUser(String email) {
-        User user = new User();
-        user.setEmail(email);
-        user.setPassword(passwordEncoder.encode("kakao_user")); // // OAuth 사용자는 비밀번호를 따로 설정하지 않음
+    public User loadOrCreateUser(String email) {
+        return userRepository.findByEmail(email)
+                .orElseGet(() -> {
+                    User user = new User();
+                    user.setEmail(email);
+                    user.setPassword(passwordEncoder.encode("kakao_user")); // OAuth 사용자는 임시 비밀번호
 
-        userRepository.save(user);
+                    user.setRole("USER"); // 기본 역할 설정
+
+                    return userRepository.save(user);
+                });
     }
 
     /**
@@ -112,8 +117,12 @@ public AuthResponseDTO login(AuthRequestDTO authRequestDTO) {
 
         String jwt = jwtTokenProvider.createToken(authentication);
 
+        User user = userRepository.findByEmail(authRequestDTO.getEmail())
+                .orElseThrow(() -> new RuntimeException("User not found"));
+
         logger.info("Login successful for email: {}", authRequestDTO.getEmail());
-        return new AuthResponseDTO(jwt, authRequestDTO.getEmail());
+
+        return new AuthResponseDTO(jwt, authRequestDTO.getEmail(), String.valueOf(user.getUserId()));
     }
 
 
diff --git a/src/main/java/com/sayup/SayUp/service/ChatRoomService.java b/src/main/java/com/sayup/SayUp/service/ChatRoomService.java
new file mode 100644
index 0000000..363fb43
--- /dev/null
+++ b/src/main/java/com/sayup/SayUp/service/ChatRoomService.java
@@ -0,0 +1,56 @@
+package com.sayup.SayUp.service;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.sayup.SayUp.entity.ChatRoom;
+import com.sayup.SayUp.entity.User;
+import com.sayup.SayUp.repository.ChatRoomRepository;
+import com.sayup.SayUp.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+@Service
+@RequiredArgsConstructor
+public class ChatRoomService {
+
+    private final ChatRoomRepository chatRoomRepository;
+    private final UserRepository userRepository;
+    private final ObjectMapper objectMapper;
+
+    /**
+     * 두 사용자가 참여하는 채팅방이 이미 존재하면 해당 방을 반환
+     * 없으면 새 채팅방을 생성하여 반환
+     *
+     * @param currentUserId 현재 로그인한 유저의 ID
+     * @param friendUserId 친구로 선택한 유저의 ID
+     * @return 기존 또는 새로 생성된 채팅방
+     * @throws Exception JSON 변환 실패 등 예외 발생 시
+     */
+    public ChatRoom createOrEnterRoom(Long currentUserId, Long friendUserId) throws Exception {
+        // 두 사용자 간의 기존 채팅방이 존재하는지 확인
+        Optional<ChatRoom> existingRoom = chatRoomRepository.findByUserIds(currentUserId, friendUserId);
+        if (existingRoom.isPresent()) return existingRoom.get();
+
+        // 사용자 정보 조회 (존재하지 않으면 예외 발생)
+        User currentUser = userRepository.findById(currentUserId).orElseThrow();
+        User friendUser = userRepository.findById(friendUserId).orElseThrow();
+
+        // 친구의 TTS 벡터를 메타데이터에 저장 (key: tts_vector_{friendUserId})
+        Map<String, Object> metadataMap = new HashMap<>();
+        metadataMap.put("tts_vector_" + friendUserId, friendUser.getTtsVector());
+
+        String metadataJson = objectMapper.writeValueAsString(metadataMap);
+
+        // 새로운 채팅방 객체 생성 및 저장
+        ChatRoom room = ChatRoom.builder()
+                .participants(Arrays.asList(currentUser, friendUser))
+                .metadata(metadataJson)
+                .build();
+
+        return chatRoomRepository.save(room);
+    }
+}
diff --git a/src/main/java/com/sayup/SayUp/service/FriendshipService.java b/src/main/java/com/sayup/SayUp/service/FriendshipService.java
index 9e12fdf..888f524 100644
--- a/src/main/java/com/sayup/SayUp/service/FriendshipService.java
+++ b/src/main/java/com/sayup/SayUp/service/FriendshipService.java
@@ -29,8 +29,11 @@ public class FriendshipService {
     @Autowired
     private UserRepository userRepository;
 
+    /**
+     * @param addresseeId: 친구 요청을 받을 사용자의 userId
+     */
     @Transactional
-    public void sendFriendRequest(CustomUserDetails requesterDetails, Integer addresseeId) {
+    public void sendFriendRequest(CustomUserDetails requesterDetails, Long addresseeId) {
         User requester = requesterDetails.getUser(); // User 객체 직접 접근
         User addressee = userRepository.findById(addresseeId)
                 .orElseThrow(() -> new RuntimeException("User not found"));
@@ -65,6 +68,17 @@ public void sendFriendRequest(CustomUserDetails requesterDetails, Integer addres
         friendshipRepository.save(relationship);
     }
 
+    /**
+     * 전체 흐름 정리
+     * 1. A 유저가 B에게 친구 요청 
+     *    서버에서 FriendRelationship 생성 -> relationshipId 생성
+     * 2. B 유저가 getPendingRequests() API 호출
+     *    B를 향한 PENDING 상태의 요청들을 조회
+     *    각 요청마다 relationshipId + 요청자 정보 반환
+     * 3. B 유저가 특정 요청을 수락
+     *    /friend/accept API 호출 시 relationshipId 전달
+     *    서버에서 해당 요청의 상태를 ACCEPTED로 변경
+     */
     @Transactional
     public void acceptFriendRequest(CustomUserDetails addresseeDetails, Long relationshipId) {
         User addressee = addresseeDetails.getUser();
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index 803c755..638d322 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -41,4 +41,4 @@ springdoc.swagger-ui.operations-sorter=alpha
 springdoc.packages-to-scan=com.sayup.SayUp.controller
 
 kakao.client_id=${KAKAO}
-kakao.redirect_uri=http://localhost:8080/callback
+kakao.redirect_uri=http://localhost:8080/api/auth/kakao/callback
diff --git a/src/main/resources/templates/login.html b/src/main/resources/templates/login.html
deleted file mode 100644
index bdacabc..0000000
--- a/src/main/resources/templates/login.html
+++ /dev/null
@@ -1,15 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <title>KakaoLogin</title>
-</head>
-<body>
-<div class="container" style="display: flex; justify-content: center; align-content: center; align-items: center; flex-direction: column; margin: 200px auto; ">
-    <h1>카카오 로그인</h1>
-    <a th:href="${location}">
-        <img src="/kakao_login_medium_narrow.png" >
-    </a>
-</div>
-</body>
-</html>
\ No newline at end of file