diff --git a/api/src/main/java/org/sopt/common/ApiResponse.java b/api/src/main/java/org/sopt/api/common/ApiResponse.java
similarity index 96%
rename from api/src/main/java/org/sopt/common/ApiResponse.java
rename to api/src/main/java/org/sopt/api/common/ApiResponse.java
index 6154735..c785d3c 100644
--- a/api/src/main/java/org/sopt/common/ApiResponse.java
+++ b/api/src/main/java/org/sopt/api/common/ApiResponse.java
@@ -1,11 +1,11 @@
-package org.sopt.common;
+package org.sopt.api.common;
 
 import com.fasterxml.jackson.annotation.JsonInclude;
 import lombok.AccessLevel;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Getter;
-import org.sopt.error.ErrorStatus;
+import org.sopt.common.error.ErrorStatus;
 import org.springframework.http.ResponseEntity;
 
 @Builder(access = AccessLevel.PRIVATE)
diff --git a/api/src/main/java/org/sopt/common/SuccessStatus.java b/api/src/main/java/org/sopt/api/common/SuccessStatus.java
similarity index 93%
rename from api/src/main/java/org/sopt/common/SuccessStatus.java
rename to api/src/main/java/org/sopt/api/common/SuccessStatus.java
index 15188b1..d5480f4 100644
--- a/api/src/main/java/org/sopt/common/SuccessStatus.java
+++ b/api/src/main/java/org/sopt/api/common/SuccessStatus.java
@@ -1,4 +1,4 @@
-package org.sopt.common;
+package org.sopt.api.common;
 
 import lombok.AccessLevel;
 import lombok.Getter;
diff --git a/api/src/main/java/org/sopt/error/GlobalExceptionHandler.java b/api/src/main/java/org/sopt/api/error/GlobalExceptionHandler.java
similarity index 88%
rename from api/src/main/java/org/sopt/error/GlobalExceptionHandler.java
rename to api/src/main/java/org/sopt/api/error/GlobalExceptionHandler.java
index 854034a..931b85c 100644
--- a/api/src/main/java/org/sopt/error/GlobalExceptionHandler.java
+++ b/api/src/main/java/org/sopt/api/error/GlobalExceptionHandler.java
@@ -1,7 +1,9 @@
-package org.sopt.error;
+package org.sopt.api.error;
 
 import lombok.extern.slf4j.Slf4j;
-import org.sopt.common.ApiResponse;
+import org.sopt.api.common.ApiResponse;
+import org.sopt.common.error.BusinessException;
+import org.sopt.common.error.ErrorStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.HttpRequestMethodNotSupportedException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
diff --git a/api/src/main/java/org/sopt/member/api/MemberApiController.java b/api/src/main/java/org/sopt/api/member/api/MemberApiController.java
similarity index 82%
rename from api/src/main/java/org/sopt/member/api/MemberApiController.java
rename to api/src/main/java/org/sopt/api/member/api/MemberApiController.java
index 0fb8372..cf6ec07 100644
--- a/api/src/main/java/org/sopt/member/api/MemberApiController.java
+++ b/api/src/main/java/org/sopt/api/member/api/MemberApiController.java
@@ -1,13 +1,13 @@
-package org.sopt.member.api;
+package org.sopt.api.member.api;
 
 import lombok.RequiredArgsConstructor;
-import org.sopt.common.ApiResponse;
-import org.sopt.common.SuccessStatus;
-import org.sopt.member.dto.request.MemberSaveRequest;
-import org.sopt.member.dto.request.MemberUpdateRequest;
-import org.sopt.member.dto.response.MemberGetResponse;
-import org.sopt.member.dto.response.MemberSaveResponse;
-import org.sopt.member.service.MemberService;
+import org.sopt.api.common.ApiResponse;
+import org.sopt.api.common.SuccessStatus;
+import org.sopt.api.member.dto.request.MemberSaveRequest;
+import org.sopt.api.member.dto.request.MemberUpdateRequest;
+import org.sopt.api.member.dto.response.MemberGetResponse;
+import org.sopt.api.member.dto.response.MemberSaveResponse;
+import org.sopt.api.member.service.MemberService;
 import org.springframework.data.domain.Pageable;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
diff --git a/api/src/main/java/org/sopt/member/dto/request/MemberSaveRequest.java b/api/src/main/java/org/sopt/api/member/dto/request/MemberSaveRequest.java
similarity index 59%
rename from api/src/main/java/org/sopt/member/dto/request/MemberSaveRequest.java
rename to api/src/main/java/org/sopt/api/member/dto/request/MemberSaveRequest.java
index 9a4917c..b891b19 100644
--- a/api/src/main/java/org/sopt/member/dto/request/MemberSaveRequest.java
+++ b/api/src/main/java/org/sopt/api/member/dto/request/MemberSaveRequest.java
@@ -1,6 +1,6 @@
-package org.sopt.member.dto.request;
+package org.sopt.api.member.dto.request;
 
-import org.sopt.member.domain.Sopt;
+import org.sopt.domain.member.domain.Sopt;
 
 public record MemberSaveRequest(
         String name,
diff --git a/api/src/main/java/org/sopt/member/dto/request/MemberUpdateRequest.java b/api/src/main/java/org/sopt/api/member/dto/request/MemberUpdateRequest.java
similarity index 50%
rename from api/src/main/java/org/sopt/member/dto/request/MemberUpdateRequest.java
rename to api/src/main/java/org/sopt/api/member/dto/request/MemberUpdateRequest.java
index a4bed65..34123fd 100644
--- a/api/src/main/java/org/sopt/member/dto/request/MemberUpdateRequest.java
+++ b/api/src/main/java/org/sopt/api/member/dto/request/MemberUpdateRequest.java
@@ -1,6 +1,6 @@
-package org.sopt.member.dto.request;
+package org.sopt.api.member.dto.request;
 
-import org.sopt.member.domain.Part;
+import org.sopt.domain.member.domain.Part;
 
 public record MemberUpdateRequest(
         int generation,
diff --git a/api/src/main/java/org/sopt/member/dto/response/MemberGetResponse.java b/api/src/main/java/org/sopt/api/member/dto/response/MemberGetResponse.java
similarity index 79%
rename from api/src/main/java/org/sopt/member/dto/response/MemberGetResponse.java
rename to api/src/main/java/org/sopt/api/member/dto/response/MemberGetResponse.java
index d760ab5..93578fe 100644
--- a/api/src/main/java/org/sopt/member/dto/response/MemberGetResponse.java
+++ b/api/src/main/java/org/sopt/api/member/dto/response/MemberGetResponse.java
@@ -1,9 +1,9 @@
-package org.sopt.member.dto.response;
+package org.sopt.api.member.dto.response;
 
 import lombok.AccessLevel;
 import lombok.Builder;
-import org.sopt.member.domain.Member;
-import org.sopt.member.domain.Sopt;
+import org.sopt.domain.member.domain.Member;
+import org.sopt.domain.member.domain.Sopt;
 
 @Builder(access = AccessLevel.PRIVATE)
 public record MemberGetResponse(
diff --git a/api/src/main/java/org/sopt/member/dto/response/MemberSaveResponse.java b/api/src/main/java/org/sopt/api/member/dto/response/MemberSaveResponse.java
similarity index 67%
rename from api/src/main/java/org/sopt/member/dto/response/MemberSaveResponse.java
rename to api/src/main/java/org/sopt/api/member/dto/response/MemberSaveResponse.java
index 0c81327..7137d00 100644
--- a/api/src/main/java/org/sopt/member/dto/response/MemberSaveResponse.java
+++ b/api/src/main/java/org/sopt/api/member/dto/response/MemberSaveResponse.java
@@ -1,6 +1,6 @@
-package org.sopt.member.dto.response;
+package org.sopt.api.member.dto.response;
 
-import org.sopt.member.domain.Member;
+import org.sopt.domain.member.domain.Member;
 
 public record MemberSaveResponse(
         Long memberId
diff --git a/api/src/main/java/org/sopt/member/service/MemberService.java b/api/src/main/java/org/sopt/api/member/service/MemberService.java
similarity index 76%
rename from api/src/main/java/org/sopt/member/service/MemberService.java
rename to api/src/main/java/org/sopt/api/member/service/MemberService.java
index e885ffd..9819cb8 100644
--- a/api/src/main/java/org/sopt/member/service/MemberService.java
+++ b/api/src/main/java/org/sopt/api/member/service/MemberService.java
@@ -1,22 +1,22 @@
-package org.sopt.member.service;
+package org.sopt.api.member.service;
 
 import lombok.RequiredArgsConstructor;
-import org.sopt.error.ConflictException;
-import org.sopt.error.ErrorStatus;
-import org.sopt.member.domain.Member;
-import org.sopt.member.domain.Sopt;
-import org.sopt.member.dto.request.MemberSaveRequest;
-import org.sopt.member.dto.request.MemberUpdateRequest;
-import org.sopt.member.dto.response.MemberGetResponse;
-import org.sopt.member.dto.response.MemberSaveResponse;
-import org.sopt.member.repository.MemberRepository;
+import org.sopt.common.error.ConflictException;
+import org.sopt.common.error.ErrorStatus;
+import org.sopt.domain.member.domain.Member;
+import org.sopt.domain.member.domain.Sopt;
+import org.sopt.api.member.dto.request.MemberSaveRequest;
+import org.sopt.api.member.dto.request.MemberUpdateRequest;
+import org.sopt.api.member.dto.response.MemberGetResponse;
+import org.sopt.api.member.dto.response.MemberSaveResponse;
+import org.sopt.domain.member.repository.MemberRepository;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import java.util.List;
 
-import static org.sopt.member.domain.Member.createMember;
+import static org.sopt.domain.member.domain.Member.createMember;
 
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
diff --git a/api/src/main/java/org/sopt/post/api/PostApiController.java b/api/src/main/java/org/sopt/api/post/api/PostApiController.java
similarity index 86%
rename from api/src/main/java/org/sopt/post/api/PostApiController.java
rename to api/src/main/java/org/sopt/api/post/api/PostApiController.java
index c784a45..c822e41 100644
--- a/api/src/main/java/org/sopt/post/api/PostApiController.java
+++ b/api/src/main/java/org/sopt/api/post/api/PostApiController.java
@@ -1,12 +1,12 @@
-package org.sopt.post.api;
+package org.sopt.api.post.api;
 
 import lombok.RequiredArgsConstructor;
-import org.sopt.common.ApiResponse;
-import org.sopt.common.SuccessStatus;
-import org.sopt.post.dto.request.PostSaveOrUpdateRequest;
-import org.sopt.post.dto.response.PostGetResponse;
-import org.sopt.post.dto.response.PostSaveResponse;
-import org.sopt.post.service.PostService;
+import org.sopt.api.common.ApiResponse;
+import org.sopt.api.common.SuccessStatus;
+import org.sopt.api.post.dto.request.PostSaveOrUpdateRequest;
+import org.sopt.api.post.dto.response.PostGetResponse;
+import org.sopt.api.post.dto.response.PostSaveResponse;
+import org.sopt.api.post.service.PostService;
 import org.springframework.data.domain.Pageable;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
diff --git a/api/src/main/java/org/sopt/post/dto/request/PostSaveOrUpdateRequest.java b/api/src/main/java/org/sopt/api/post/dto/request/PostSaveOrUpdateRequest.java
similarity index 76%
rename from api/src/main/java/org/sopt/post/dto/request/PostSaveOrUpdateRequest.java
rename to api/src/main/java/org/sopt/api/post/dto/request/PostSaveOrUpdateRequest.java
index f35e65f..e0c8474 100644
--- a/api/src/main/java/org/sopt/post/dto/request/PostSaveOrUpdateRequest.java
+++ b/api/src/main/java/org/sopt/api/post/dto/request/PostSaveOrUpdateRequest.java
@@ -1,4 +1,4 @@
-package org.sopt.post.dto.request;
+package org.sopt.api.post.dto.request;
 
 public record PostSaveOrUpdateRequest(
         String title,
diff --git a/api/src/main/java/org/sopt/post/dto/response/PostGetResponse.java b/api/src/main/java/org/sopt/api/post/dto/response/PostGetResponse.java
similarity index 80%
rename from api/src/main/java/org/sopt/post/dto/response/PostGetResponse.java
rename to api/src/main/java/org/sopt/api/post/dto/response/PostGetResponse.java
index 9661b7d..4263163 100644
--- a/api/src/main/java/org/sopt/post/dto/response/PostGetResponse.java
+++ b/api/src/main/java/org/sopt/api/post/dto/response/PostGetResponse.java
@@ -1,9 +1,9 @@
-package org.sopt.post.dto.response;
+package org.sopt.api.post.dto.response;
 
 import lombok.AccessLevel;
 import lombok.Builder;
-import org.sopt.post.domain.Category;
-import org.sopt.post.domain.Post;
+import org.sopt.domain.post.domain.Category;
+import org.sopt.domain.post.domain.Post;
 
 @Builder(access = AccessLevel.PRIVATE)
 public record PostGetResponse(
diff --git a/api/src/main/java/org/sopt/post/dto/response/PostSaveResponse.java b/api/src/main/java/org/sopt/api/post/dto/response/PostSaveResponse.java
similarity index 67%
rename from api/src/main/java/org/sopt/post/dto/response/PostSaveResponse.java
rename to api/src/main/java/org/sopt/api/post/dto/response/PostSaveResponse.java
index 2c3a9bc..b389831 100644
--- a/api/src/main/java/org/sopt/post/dto/response/PostSaveResponse.java
+++ b/api/src/main/java/org/sopt/api/post/dto/response/PostSaveResponse.java
@@ -1,6 +1,6 @@
-package org.sopt.post.dto.response;
+package org.sopt.api.post.dto.response;
 
-import org.sopt.post.domain.Post;
+import org.sopt.domain.post.domain.Post;
 
 public record PostSaveResponse(
         Long postId
diff --git a/api/src/main/java/org/sopt/post/service/PostService.java b/api/src/main/java/org/sopt/api/post/service/PostService.java
similarity index 67%
rename from api/src/main/java/org/sopt/post/service/PostService.java
rename to api/src/main/java/org/sopt/api/post/service/PostService.java
index a0f1872..a44940f 100644
--- a/api/src/main/java/org/sopt/post/service/PostService.java
+++ b/api/src/main/java/org/sopt/api/post/service/PostService.java
@@ -1,21 +1,27 @@
-package org.sopt.post.service;
+package org.sopt.api.post.service;
 
 import lombok.RequiredArgsConstructor;
-import org.sopt.member.domain.Member;
-import org.sopt.member.repository.MemberRepository;
-import org.sopt.post.domain.Category;
-import org.sopt.post.domain.Post;
-import org.sopt.post.dto.request.PostSaveOrUpdateRequest;
-import org.sopt.post.dto.response.PostGetResponse;
-import org.sopt.post.dto.response.PostSaveResponse;
-import org.sopt.post.repository.CategoryRepository;
-import org.sopt.post.repository.PostRepository;
+import org.sopt.common.error.ConflictException;
+import org.sopt.common.error.ErrorStatus;
+import org.sopt.domain.member.domain.Member;
+import org.sopt.domain.member.repository.MemberRepository;
+import org.sopt.domain.post.domain.Category;
+import org.sopt.domain.post.domain.Post;
+import org.sopt.api.post.dto.request.PostSaveOrUpdateRequest;
+import org.sopt.api.post.dto.response.PostGetResponse;
+import org.sopt.api.post.dto.response.PostSaveResponse;
+
+import org.sopt.domain.post.repository.CategoryRepository;
+import org.sopt.domain.post.repository.PostRepository;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import java.util.List;
 
+import static org.sopt.domain.post.domain.Category.createCategory;
+import static org.sopt.domain.post.domain.Post.createPost;
+
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
 @Service
@@ -27,6 +33,7 @@ public class PostService {
     @Transactional
     public PostSaveResponse savePost(Long memberId, PostSaveOrUpdateRequest postSaveOrUpdateRequest) {
         Member findMember = findMember(memberId);
+        validateDuplicateCategory(postSaveOrUpdateRequest.categoryContent());
         Category savedCategory = createCategoryAndGetSavedCategory(postSaveOrUpdateRequest);
         Post savedPost = createPostAndGetSavedPost(postSaveOrUpdateRequest, findMember, savedCategory);
         return PostSaveResponse.of(savedPost);
@@ -60,13 +67,19 @@ private Member findMember(Long memberId) {
         return memberRepository.findByIdOrThrow(memberId);
     }
 
+    private void validateDuplicateCategory(String content) {
+        if (categoryRepository.existsByContent(content)) {
+            throw new ConflictException(ErrorStatus.DUPLICATE_CATEGORY);
+        }
+    }
+
     private Category createCategoryAndGetSavedCategory(PostSaveOrUpdateRequest postSaveOrUpdateRequest) {
-        Category category = Category.createCategory(postSaveOrUpdateRequest.categoryContent());
+        Category category = createCategory(postSaveOrUpdateRequest.categoryContent());
         return categoryRepository.save(category);
     }
 
     private Post createPostAndGetSavedPost(PostSaveOrUpdateRequest postSaveOrUpdateRequest, Member member, Category category) {
-        Post post = Post.createPost(postSaveOrUpdateRequest.title(), postSaveOrUpdateRequest.postContent(), category, member);
+        Post post = createPost(postSaveOrUpdateRequest.title(), postSaveOrUpdateRequest.postContent(), category, member);
         return postRepository.save(post);
     }
 
diff --git a/build.gradle b/build.gradle
index 039b00d..6803218 100644
--- a/build.gradle
+++ b/build.gradle
@@ -38,7 +38,11 @@ subprojects {
         useJUnitPlatform()
     }
 
-    jar {
+    bootJar {
         enabled = false
     }
+
+    jar {
+        enabled = true
+    }
 }
\ No newline at end of file
diff --git a/common/src/main/java/org/sopt/error/BusinessException.java b/common/src/main/java/org/sopt/common/error/BusinessException.java
similarity index 90%
rename from common/src/main/java/org/sopt/error/BusinessException.java
rename to common/src/main/java/org/sopt/common/error/BusinessException.java
index 770e4a8..0f2da61 100644
--- a/common/src/main/java/org/sopt/error/BusinessException.java
+++ b/common/src/main/java/org/sopt/common/error/BusinessException.java
@@ -1,4 +1,4 @@
-package org.sopt.error;
+package org.sopt.common.error;
 
 import lombok.Getter;
 
diff --git a/common/src/main/java/org/sopt/error/ConflictException.java b/common/src/main/java/org/sopt/common/error/ConflictException.java
similarity index 88%
rename from common/src/main/java/org/sopt/error/ConflictException.java
rename to common/src/main/java/org/sopt/common/error/ConflictException.java
index 964e6b1..274160c 100644
--- a/common/src/main/java/org/sopt/error/ConflictException.java
+++ b/common/src/main/java/org/sopt/common/error/ConflictException.java
@@ -1,4 +1,4 @@
-package org.sopt.error;
+package org.sopt.common.error;
 
 public class ConflictException extends BusinessException {
     public ConflictException() {
diff --git a/common/src/main/java/org/sopt/error/EntityNotFoundException.java b/common/src/main/java/org/sopt/common/error/EntityNotFoundException.java
similarity index 89%
rename from common/src/main/java/org/sopt/error/EntityNotFoundException.java
rename to common/src/main/java/org/sopt/common/error/EntityNotFoundException.java
index 9793f50..5f11799 100644
--- a/common/src/main/java/org/sopt/error/EntityNotFoundException.java
+++ b/common/src/main/java/org/sopt/common/error/EntityNotFoundException.java
@@ -1,4 +1,4 @@
-package org.sopt.error;
+package org.sopt.common.error;
 
 public class EntityNotFoundException extends BusinessException {
     public EntityNotFoundException() {
diff --git a/common/src/main/java/org/sopt/error/ErrorStatus.java b/common/src/main/java/org/sopt/common/error/ErrorStatus.java
similarity index 90%
rename from common/src/main/java/org/sopt/error/ErrorStatus.java
rename to common/src/main/java/org/sopt/common/error/ErrorStatus.java
index 37083ff..56fa0ac 100644
--- a/common/src/main/java/org/sopt/error/ErrorStatus.java
+++ b/common/src/main/java/org/sopt/common/error/ErrorStatus.java
@@ -1,4 +1,4 @@
-package org.sopt.error;
+package org.sopt.common.error;
 
 import lombok.AccessLevel;
 import lombok.Getter;
@@ -30,6 +30,7 @@ public enum ErrorStatus {
      */
     CONFLICT(HttpStatus.CONFLICT, "이미 존재하는 리소스입니다."),
     DUPLICATE_MEMBER(HttpStatus.CONFLICT, "이미 존재하는 회원입니다."),
+    DUPLICATE_CATEGORY(HttpStatus.CONFLICT, "이미 존재하는 카테고리입니다."),
 
     /**
      * 500 Internal Server Error
diff --git a/common/src/main/java/org/sopt/error/InvalidValueException.java b/common/src/main/java/org/sopt/common/error/InvalidValueException.java
similarity index 88%
rename from common/src/main/java/org/sopt/error/InvalidValueException.java
rename to common/src/main/java/org/sopt/common/error/InvalidValueException.java
index ecc8b88..ec7a515 100644
--- a/common/src/main/java/org/sopt/error/InvalidValueException.java
+++ b/common/src/main/java/org/sopt/common/error/InvalidValueException.java
@@ -1,4 +1,4 @@
-package org.sopt.error;
+package org.sopt.common.error;
 
 public class InvalidValueException extends BusinessException {
     public InvalidValueException() {
diff --git a/domain/src/main/java/org/sopt/common/BaseTimeEntity.java b/domain/src/main/java/org/sopt/domain/common/BaseTimeEntity.java
similarity index 95%
rename from domain/src/main/java/org/sopt/common/BaseTimeEntity.java
rename to domain/src/main/java/org/sopt/domain/common/BaseTimeEntity.java
index 8e5797a..1a8475f 100644
--- a/domain/src/main/java/org/sopt/common/BaseTimeEntity.java
+++ b/domain/src/main/java/org/sopt/domain/common/BaseTimeEntity.java
@@ -1,4 +1,4 @@
-package org.sopt.common;
+package org.sopt.domain.common;
 
 import jakarta.persistence.Column;
 import jakarta.persistence.EntityListeners;
diff --git a/domain/src/main/java/org/sopt/config/JpaConfig.java b/domain/src/main/java/org/sopt/domain/config/JpaConfig.java
similarity index 86%
rename from domain/src/main/java/org/sopt/config/JpaConfig.java
rename to domain/src/main/java/org/sopt/domain/config/JpaConfig.java
index e0ea3c1..69facbd 100644
--- a/domain/src/main/java/org/sopt/config/JpaConfig.java
+++ b/domain/src/main/java/org/sopt/domain/config/JpaConfig.java
@@ -1,4 +1,4 @@
-package org.sopt.config;
+package org.sopt.domain.config;
 
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
diff --git a/domain/src/main/java/org/sopt/member/domain/Member.java b/domain/src/main/java/org/sopt/domain/member/domain/Member.java
similarity index 90%
rename from domain/src/main/java/org/sopt/member/domain/Member.java
rename to domain/src/main/java/org/sopt/domain/member/domain/Member.java
index a645dcd..e2d767c 100644
--- a/domain/src/main/java/org/sopt/member/domain/Member.java
+++ b/domain/src/main/java/org/sopt/domain/member/domain/Member.java
@@ -1,10 +1,10 @@
-package org.sopt.member.domain;
+package org.sopt.domain.member.domain;
 
 import jakarta.persistence.*;
 import lombok.*;
 import org.hibernate.annotations.DynamicUpdate;
-import org.sopt.common.BaseTimeEntity;
-import org.sopt.post.domain.Post;
+import org.sopt.domain.common.BaseTimeEntity;
+import org.sopt.domain.post.domain.Post;
 
 import java.util.ArrayList;
 import java.util.List;
diff --git a/domain/src/main/java/org/sopt/member/domain/Part.java b/domain/src/main/java/org/sopt/domain/member/domain/Part.java
similarity index 88%
rename from domain/src/main/java/org/sopt/member/domain/Part.java
rename to domain/src/main/java/org/sopt/domain/member/domain/Part.java
index fbec7c5..9ad1a88 100644
--- a/domain/src/main/java/org/sopt/member/domain/Part.java
+++ b/domain/src/main/java/org/sopt/domain/member/domain/Part.java
@@ -1,4 +1,4 @@
-package org.sopt.member.domain;
+package org.sopt.domain.member.domain;
 
 import lombok.AccessLevel;
 import lombok.Getter;
diff --git a/domain/src/main/java/org/sopt/member/domain/Sopt.java b/domain/src/main/java/org/sopt/domain/member/domain/Sopt.java
similarity index 93%
rename from domain/src/main/java/org/sopt/member/domain/Sopt.java
rename to domain/src/main/java/org/sopt/domain/member/domain/Sopt.java
index c737f01..385afc1 100644
--- a/domain/src/main/java/org/sopt/member/domain/Sopt.java
+++ b/domain/src/main/java/org/sopt/domain/member/domain/Sopt.java
@@ -1,4 +1,4 @@
-package org.sopt.member.domain;
+package org.sopt.domain.member.domain;
 
 import jakarta.persistence.Embeddable;
 import jakarta.persistence.EnumType;
diff --git a/domain/src/main/java/org/sopt/member/repository/MemberRepository.java b/domain/src/main/java/org/sopt/domain/member/repository/MemberRepository.java
similarity index 66%
rename from domain/src/main/java/org/sopt/member/repository/MemberRepository.java
rename to domain/src/main/java/org/sopt/domain/member/repository/MemberRepository.java
index e727293..551173c 100644
--- a/domain/src/main/java/org/sopt/member/repository/MemberRepository.java
+++ b/domain/src/main/java/org/sopt/domain/member/repository/MemberRepository.java
@@ -1,8 +1,8 @@
-package org.sopt.member.repository;
+package org.sopt.domain.member.repository;
 
-import org.sopt.error.EntityNotFoundException;
-import org.sopt.error.ErrorStatus;
-import org.sopt.member.domain.Member;
+import org.sopt.common.error.EntityNotFoundException;
+import org.sopt.common.error.ErrorStatus;
+import org.sopt.domain.member.domain.Member;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface MemberRepository extends JpaRepository<Member, Long> {
diff --git a/domain/src/main/java/org/sopt/post/domain/Category.java b/domain/src/main/java/org/sopt/domain/post/domain/Category.java
similarity index 83%
rename from domain/src/main/java/org/sopt/post/domain/Category.java
rename to domain/src/main/java/org/sopt/domain/post/domain/Category.java
index 65d2668..a0c537e 100644
--- a/domain/src/main/java/org/sopt/post/domain/Category.java
+++ b/domain/src/main/java/org/sopt/domain/post/domain/Category.java
@@ -1,8 +1,8 @@
-package org.sopt.post.domain;
+package org.sopt.domain.post.domain;
 
 import jakarta.persistence.*;
 import lombok.*;
-import org.sopt.common.BaseTimeEntity;
+import org.sopt.domain.common.BaseTimeEntity;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -14,11 +14,11 @@
 @Entity
 public class Category extends BaseTimeEntity {
     @Id
-    @GeneratedValue
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     @Column(name = "category_id")
     private Short id;
     private String content;
-    @OneToMany
+    @OneToMany(mappedBy = "category")
     @Builder.Default
     private List<Post> posts = new ArrayList<>();
 
diff --git a/domain/src/main/java/org/sopt/post/domain/Post.java b/domain/src/main/java/org/sopt/domain/post/domain/Post.java
similarity index 92%
rename from domain/src/main/java/org/sopt/post/domain/Post.java
rename to domain/src/main/java/org/sopt/domain/post/domain/Post.java
index c8ffbff..169c184 100644
--- a/domain/src/main/java/org/sopt/post/domain/Post.java
+++ b/domain/src/main/java/org/sopt/domain/post/domain/Post.java
@@ -1,9 +1,9 @@
-package org.sopt.post.domain;
+package org.sopt.domain.post.domain;
 
 import jakarta.persistence.*;
 import lombok.*;
-import org.sopt.common.BaseTimeEntity;
-import org.sopt.member.domain.Member;
+import org.sopt.domain.common.BaseTimeEntity;
+import org.sopt.domain.member.domain.Member;
 
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 @AllArgsConstructor(access = AccessLevel.PRIVATE)
diff --git a/domain/src/main/java/org/sopt/post/repository/CategoryRepository.java b/domain/src/main/java/org/sopt/domain/post/repository/CategoryRepository.java
similarity index 52%
rename from domain/src/main/java/org/sopt/post/repository/CategoryRepository.java
rename to domain/src/main/java/org/sopt/domain/post/repository/CategoryRepository.java
index 906e5c8..0909379 100644
--- a/domain/src/main/java/org/sopt/post/repository/CategoryRepository.java
+++ b/domain/src/main/java/org/sopt/domain/post/repository/CategoryRepository.java
@@ -1,7 +1,8 @@
-package org.sopt.post.repository;
+package org.sopt.domain.post.repository;
 
-import org.sopt.post.domain.Category;
+import org.sopt.domain.post.domain.Category;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface CategoryRepository extends JpaRepository<Category, Short> {
+    boolean existsByContent(String content);
 }
diff --git a/domain/src/main/java/org/sopt/post/repository/PostRepository.java b/domain/src/main/java/org/sopt/domain/post/repository/PostRepository.java
similarity index 72%
rename from domain/src/main/java/org/sopt/post/repository/PostRepository.java
rename to domain/src/main/java/org/sopt/domain/post/repository/PostRepository.java
index c753f8b..5e442db 100644
--- a/domain/src/main/java/org/sopt/post/repository/PostRepository.java
+++ b/domain/src/main/java/org/sopt/domain/post/repository/PostRepository.java
@@ -1,8 +1,8 @@
-package org.sopt.post.repository;
+package org.sopt.domain.post.repository;
 
-import org.sopt.error.EntityNotFoundException;
-import org.sopt.error.ErrorStatus;
-import org.sopt.post.domain.Post;
+import org.sopt.common.error.EntityNotFoundException;
+import org.sopt.common.error.ErrorStatus;
+import org.sopt.domain.post.domain.Post;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;