diff --git a/src/backend/file_server/Dockerfile b/src/backend/file_server/Dockerfile
new file mode 100644
index 00000000..9de44cdd
--- /dev/null
+++ b/src/backend/file_server/Dockerfile
@@ -0,0 +1,21 @@
+# Azul Zulu JDK 17 기반 이미지 사용
+FROM azul/zulu-openjdk:17
+
+# 작업 디렉토리 설정
+WORKDIR /app
+
+# 환경 변수 파일 복사
+COPY .env .env
+
+# 빌드된 JAR 파일 복사
+ARG JAR_FILE=build/libs/file_server-0.0.1-SNAPSHOT.jar
+COPY ${JAR_FILE} app.jar
+
+# 환경 변수 설정
+ENV $(cat .env)
+
+# 포트 노출
+EXPOSE 8083
+
+# 애플리케이션 실행
+ENTRYPOINT ["java", "-jar", "app.jar"]
\ No newline at end of file
diff --git a/src/backend/file_server/local.env b/src/backend/file_server/local.env
deleted file mode 100644
index e69de29b..00000000
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/controller/FileController.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/controller/FileController.java
index 1f5852d2..13e036ef 100644
--- a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/controller/FileController.java
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/controller/FileController.java
@@ -1,18 +1,26 @@
 package com.jootalkpia.file_server.controller;
 
+import com.jootalkpia.file_server.dto.ChangeProfileResponseDto;
 import com.jootalkpia.file_server.dto.UploadFileRequestDto;
 import com.jootalkpia.file_server.dto.UploadFileResponseDto;
 import com.jootalkpia.file_server.service.FileService;
+import com.jootalkpia.file_server.utils.ValidationUtils;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.core.io.InputStreamResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.multipart.MultipartFile;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
 
 @RestController
 @RequestMapping("/api/v1")
@@ -28,24 +36,54 @@ public ResponseEntity<String> testEndpoint() {
         return ResponseEntity.ok("Test successful");
     }
 
-    @PostMapping("/workspace/{workspaceId}/channel/{channelId}")
-    public ResponseEntity<UploadFileResponseDto> uploadFiles(
-            @PathVariable Long workspaceId,
-            @PathVariable Long channelId,
-            @RequestParam("files") MultipartFile[] files,
-            @RequestParam("thumbnails") MultipartFile[] thumbnails) {
-        log.info("ids: {}", workspaceId);
-        log.info("Files: {}", files != null ? files.length : "null");
-        log.info("Thumbnails: {}", thumbnails != null ? thumbnails.length : "null");
-
-        UploadFileRequestDto uploadFileRequest = new UploadFileRequestDto();
-        uploadFileRequest.setWorkspaceId(workspaceId);
-        uploadFileRequest.setChannelId(channelId);
-        uploadFileRequest.setFiles(files);
-        uploadFileRequest.setThumbnails(thumbnails);
-
-        UploadFileResponseDto response = fileService.uploadFiles(1L, uploadFileRequest);
+    @PostMapping("/files")
+    public ResponseEntity<UploadFileResponseDto> uploadFiles(@ModelAttribute UploadFileRequestDto uploadFileRequest) {
+        log.info("got uploadFileRequest: {}", uploadFileRequest);
+        ValidationUtils.validateLengthOfFilesAndThumbnails(uploadFileRequest.getFiles().length, uploadFileRequest.getThumbnails().length);
+        ValidationUtils.validateWorkSpaceId(uploadFileRequest.getWorkspaceId());
+        ValidationUtils.validateChannelId(uploadFileRequest.getChannelId());
+        ValidationUtils.validateFiles(uploadFileRequest.getFiles());
+        ValidationUtils.validateFiles(uploadFileRequest.getThumbnails());
+
+        log.info("got uploadFileRequest: {}", uploadFileRequest.getFiles().length);
+        UploadFileResponseDto response = fileService.uploadFiles(userId, uploadFileRequest);
         return ResponseEntity.ok(response);
     }
 
+    @GetMapping("/files/{fileId}")
+    public ResponseEntity<InputStreamResource> downloadFile(@PathVariable Long fileId) {
+        log.info("got downloadFile id: {}", fileId);
+        ValidationUtils.validateFileId(fileId);
+
+        ResponseInputStream<GetObjectResponse> s3InputStream = fileService.downloadFile(fileId);
+
+        // response 생성
+        long contentLength = s3InputStream.response().contentLength();
+
+        // Content-Type 가져오기 기본값: application/octet-stream
+        String contentType = s3InputStream.response().contentType() != null
+                ? s3InputStream.response().contentType()
+                : MediaType.APPLICATION_OCTET_STREAM_VALUE;
+
+        // 헤더 설정
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.parseMediaType(contentType));
+        headers.setContentLength(contentLength);
+        headers.setContentDispositionFormData("attachment", "file-" + fileId);
+
+        return ResponseEntity.ok()
+                .headers(headers)
+                .body(new InputStreamResource(s3InputStream));
+    }
+
+    @PostMapping("/{userId}/profile-image")
+    public ResponseEntity<ChangeProfileResponseDto> changeProfile(
+            @PathVariable Long userId,
+            @RequestParam("newImage") MultipartFile newImage) {
+        log.info("got new profile Image: {}", newImage);
+        ValidationUtils.validateFile(newImage);
+
+        ChangeProfileResponseDto response = fileService.changeProfile(userId, newImage);
+        return ResponseEntity.ok(response);
+    }
 }
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/dto/ChangeProfileResponseDto.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/dto/ChangeProfileResponseDto.java
new file mode 100644
index 00000000..784b3656
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/dto/ChangeProfileResponseDto.java
@@ -0,0 +1,14 @@
+package com.jootalkpia.file_server.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+@AllArgsConstructor
+public class ChangeProfileResponseDto {
+    private Long userId;
+    private String nickname;
+    private String profileImage;
+}
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/entity/BaseTimeEntity.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/entity/BaseTimeEntity.java
new file mode 100644
index 00000000..5224d39b
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/entity/BaseTimeEntity.java
@@ -0,0 +1,21 @@
+package com.jootalkpia.file_server.entity;
+
+import jakarta.persistence.EntityListeners;
+import jakarta.persistence.MappedSuperclass;
+import java.time.LocalDateTime;
+import lombok.Getter;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.annotation.LastModifiedDate;
+import org.springframework.data.jpa.domain.support.AuditingEntityListener;
+
+@Getter
+@MappedSuperclass
+@EntityListeners(AuditingEntityListener.class)
+public abstract class BaseTimeEntity {
+
+    @CreatedDate
+    private LocalDateTime createdAt;
+
+    @LastModifiedDate
+    protected LocalDateTime updatedAt;
+}
\ No newline at end of file
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/entity/User.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/entity/User.java
new file mode 100644
index 00000000..fbefac3d
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/entity/User.java
@@ -0,0 +1,39 @@
+package com.jootalkpia.file_server.entity;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@Table(name = "users")
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+public class User extends BaseTimeEntity {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long userId;
+
+    private Long socialId;
+
+    private String email;
+
+    private String platform;
+
+    private String nickname;
+
+    private String profileImage;
+
+    public void updateProfileImage(final String newProfileImage) {
+        this.profileImage = newProfileImage;
+    }
+}
\ No newline at end of file
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/CustomException.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/CustomException.java
new file mode 100644
index 00000000..5aa41be8
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/CustomException.java
@@ -0,0 +1,17 @@
+package com.jootalkpia.file_server.exception.common;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public class CustomException extends RuntimeException {
+
+    private final String code;
+
+    public CustomException(String code, String message) {
+        super(message);
+        this.code = code;
+    }
+
+}
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/ErrorCode.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/ErrorCode.java
new file mode 100644
index 00000000..e0a7df4a
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/ErrorCode.java
@@ -0,0 +1,37 @@
+package com.jootalkpia.file_server.exception.common;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum ErrorCode {
+
+    // 400 Bad Request
+    UNKNOWN("F00001", "알 수 없는 에러가 발생했습니다."),
+    BAD_REQUEST("F40001", "잘못된 요청입니다."),
+    VALIDATION_FAILED("F40002", "유효성 검증에 실패했습니다."),
+    MISSING_PARAMETER("F40003", "필수 파라미터가 누락되었습니다."),
+    INVALID_PARAMETER("F40004", "잘못된 파라미터가 포함되었습니다."),
+    MISSING_FILES("F40005", "파일이 포함되어야 합니다."),
+
+    // 404 Not Found
+    WORKSPACE_NOT_FOUND("F40401", "등록되지 않은 워크스페이스입니다."),
+    CHANNEL_NOT_FOUND("F40402", "등록되지 않은 채널입니다."),
+    USER_NOT_FOUND("F40403", "등록되지 않은 유저입니다."),
+    FILE_NOT_FOUND("F40404", "등록되지 않은 파일입니다."),
+
+    // 415 Unsupported Type
+    UNSUPPORTED_FILE_TYPE("F41501", "지원되지 않는 파일 타입입니다."),
+
+    // 500 Internal Server Error
+    INTERNAL_SERVER_ERROR("F50001", "서버 내부 오류가 발생했습니다."),
+    DATABASE_ERROR("F50002", "데이터베이스 처리 중 오류가 발생했습니다."),
+    IMAGE_UPLOAD_FAILED("F50003", "파일 업로드에 실패했습니다."),
+    IMAGE_DOWNLOAD_FAILED("F50004", "파일 다운로드 중 오류가 발생했습니다."),
+    FILE_PROCESSING_FAILED("F50005", "파일 처리 중 오류가 발생했습니다."),
+    UNEXPECTED_ERROR("F50006", "예상치 못한 오류가 발생했습니다.");
+
+    private final String code;
+    private final String msg;
+}
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/ErrorResponse.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/ErrorResponse.java
new file mode 100644
index 00000000..fd26bbec
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/ErrorResponse.java
@@ -0,0 +1,11 @@
+package com.jootalkpia.file_server.exception.common;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class ErrorResponse {
+    private String code;
+    private String message;
+}
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/GlobalExceptionHandler.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/GlobalExceptionHandler.java
new file mode 100644
index 00000000..00cb7173
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/exception/common/GlobalExceptionHandler.java
@@ -0,0 +1,22 @@
+package com.jootalkpia.file_server.exception.common;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(CustomException.class)
+    public ResponseEntity<ErrorResponse> handleCustomException(CustomException ex) {
+        ErrorResponse errorResponse = new ErrorResponse(ex.getCode(), ex.getMessage());
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponse);
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ErrorResponse> handleGenericException(Exception ex) {
+        ErrorResponse errorResponse = new ErrorResponse("UNKNOWN_ERROR", "An unexpected error occurred.");
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(errorResponse);
+    }
+}
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/FileRepository.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/FileRepository.java
index d1826565..6d5e903a 100644
--- a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/FileRepository.java
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/FileRepository.java
@@ -6,4 +6,5 @@
 
 @Repository
 public interface FileRepository extends JpaRepository<Files, Long> {
+
 }
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/UserRepository.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/UserRepository.java
new file mode 100644
index 00000000..30b03a1e
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/repository/UserRepository.java
@@ -0,0 +1,7 @@
+package com.jootalkpia.file_server.repository;
+
+import com.jootalkpia.file_server.entity.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface UserRepository extends JpaRepository<User, Long> {
+}
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileService.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileService.java
index fd62b8cb..75331647 100644
--- a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileService.java
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileService.java
@@ -1,17 +1,23 @@
 package com.jootalkpia.file_server.service;
 
+import com.jootalkpia.file_server.dto.ChangeProfileResponseDto;
 import com.jootalkpia.file_server.dto.UploadFileRequestDto;
 import com.jootalkpia.file_server.dto.UploadFileResponseDto;
 import com.jootalkpia.file_server.entity.Files;
+import com.jootalkpia.file_server.entity.User;
+import com.jootalkpia.file_server.exception.common.CustomException;
+import com.jootalkpia.file_server.exception.common.ErrorCode;
 import com.jootalkpia.file_server.repository.FileRepository;
+import com.jootalkpia.file_server.repository.UserRepository;
 import jakarta.transaction.Transactional;
+import java.util.ArrayList;
+import java.util.List;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Service;
 import org.springframework.web.multipart.MultipartFile;
-
-import java.util.ArrayList;
-import java.util.List;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
 
 @Service
 @Slf4j
@@ -20,6 +26,7 @@ public class FileService {
 
     private final FileRepository fileRepository;
     private final S3Service s3Service;
+    private final UserRepository userRepository;
 
     @Transactional
     public UploadFileResponseDto uploadFiles(Long userId, UploadFileRequestDto uploadFileRequestDto) {
@@ -29,57 +36,82 @@ public UploadFileResponseDto uploadFiles(Long userId, UploadFileRequestDto uploa
         List<String> fileTypes = new ArrayList<>();
         List<Long> fileIds = new ArrayList<>();
 
-        try {
-            if (files != null && files.length > 0) {
-                for (int i = 0; i < files.length; i++) {
-                    Long fileId = null;
-                    Files filesEntity = new Files();
-                    fileRepository.save(filesEntity);
-                    fileId = filesEntity.getFileId();
+        for (int i = 0; i < files.length; i++) {
+            Long fileId = null;
+            Files filesEntity = new Files();
+            fileRepository.save(filesEntity);
+            fileId = filesEntity.getFileId();
 
-                    MultipartFile file = files[i];
+            MultipartFile file = files[i];
 
-                    // 파일 타입 결정
-                    String fileType = FileTypeDetector.detectFileTypeFromMultipartFile(file);
+            // 파일 타입 결정
+            String fileType = FileTypeDetector.detectFileTypeFromMultipartFile(file);
+            log.info(fileType);
 
-                    // S3에 업로드
-                    String s3Url = s3Service.uploadFile(file, fileType, fileId);
+            String s3Url = uploadEachFile(fileType, fileId, file);
 
-                    // DB에 파일 저장
-                    filesEntity.setUrl(s3Url);
-                    filesEntity.setFileType(fileType);
-                    filesEntity.setMimeType(file.getContentType());
-                    filesEntity.setFileSize(file.getSize());
-                    fileRepository.save(filesEntity);
+            filesEntity.setUrl(s3Url);
+            filesEntity.setMimeType(file.getContentType());
+            filesEntity.setFileType(fileType);
+            filesEntity.setFileSize(file.getSize());
 
-                    fileIds.add(filesEntity.getFileId());
-                    fileTypes.add(filesEntity.getFileType());
+            fileIds.add(filesEntity.getFileId());
+            fileTypes.add(filesEntity.getFileType());
 
-                    // 영상 파일일 경우 썸네일 처리
-                    if ("VIDEO".equalsIgnoreCase(fileType) && thumbnails != null && i < thumbnails.length && thumbnails[i] != null) {
-                        fileId = null;
-                        filesEntity = new Files();
-                        fileRepository.save(filesEntity);
-                        fileId = filesEntity.getFileId();
+            if ("VIDEO".equalsIgnoreCase(fileType) && thumbnails != null && i < thumbnails.length && thumbnails[i] != null) {
+                MultipartFile thumbnail = thumbnails[i];
+                String thumbnailUrl = uploadEachFile(fileType, fileId, thumbnail);
+                filesEntity.setUrlThumbnail(thumbnailUrl);
+            }
+            fileRepository.save(filesEntity);
+        }
+        return new UploadFileResponseDto(fileTypes, fileIds);
+    }
 
-                        MultipartFile thumbnail = thumbnails[i];
-                        String thumbnailUrl = s3Service.uploadFile(thumbnail, "THUMBNAIL", fileId);
+    private String uploadEachFile(String fileType, Long fileId, MultipartFile file) {
+        String folder = defineFolderToUpload(fileType) + "/";
+        return s3Service.uploadFile(file, folder, fileId);
+    }
 
-                        filesEntity.setUrlThumbnail(thumbnailUrl);
+    public ResponseInputStream<GetObjectResponse> downloadFile(Long fileId) {
+        // 파일 조회
+        Files fileEntity = fileRepository.findById(fileId)
+                .orElseThrow(() -> new CustomException(ErrorCode.FILE_NOT_FOUND.getCode(), ErrorCode.FILE_NOT_FOUND.getMsg()));
 
-                        fileRepository.save(filesEntity);
+        // 폴더 결정
+        String folder = defineFolderToUpload(fileEntity.getFileType());
 
-//                        fileIds.add(filesEntity.getFileId());
-//                        fileTypes.add("THUMBNAIL");
-                    }
-                }
-            }
+        // S3에서 파일 다운로드
+        return s3Service.downloadFile(folder, fileId);
+    }
+
+    public String defineFolderToUpload(String fileType) {
+        if ("VIDEO".equalsIgnoreCase(fileType)) {
+            return "videos";
+        } else if ("IMAGE".equalsIgnoreCase(fileType)) {
+            return "images";
+        } else if ("THUMBNAIL".equalsIgnoreCase(fileType)) {
+            return "thumbnails";
+        } else {
+            throw new CustomException(ErrorCode.FILE_PROCESSING_FAILED.getCode(), ErrorCode.FILE_PROCESSING_FAILED.getMsg());
+        }
+    }
+
+    @Transactional
+    public ChangeProfileResponseDto changeProfile(Long userId, MultipartFile newImage) {
+        User user = userRepository.findById(userId)
+                .orElseThrow(() -> new CustomException(ErrorCode.USER_NOT_FOUND.getCode(), ErrorCode.USER_NOT_FOUND.getMsg()));
+
+        try {
+            String fileType = FileTypeDetector.detectFileTypeFromMultipartFile(newImage);
+            String s3Url = uploadEachFile(fileType, userId, newImage);
 
-            return new UploadFileResponseDto(fileTypes, fileIds);
+            user.updateProfileImage(s3Url);
+            userRepository.save(user);
 
+            return new ChangeProfileResponseDto(userId, user.getNickname(), s3Url);
         } catch (Exception e) {
-            log.error("파일 업로드 중 오류 발생: {}", e.getMessage(), e);
-            throw new RuntimeException("파일 업로드 중 오류가 발생했습니다.");
+            throw new CustomException(ErrorCode.IMAGE_UPLOAD_FAILED.getCode(), ErrorCode.IMAGE_UPLOAD_FAILED.getMsg());
         }
     }
 }
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileTypeDetector.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileTypeDetector.java
index 65bd22a2..9622c487 100644
--- a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileTypeDetector.java
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/FileTypeDetector.java
@@ -1,19 +1,20 @@
 package com.jootalkpia.file_server.service;
 
+import com.jootalkpia.file_server.exception.common.CustomException;
+import com.jootalkpia.file_server.exception.common.ErrorCode;
 import java.io.IOException;
+import java.io.InputStream;
 import org.apache.tika.Tika;
-import org.apache.tika.mime.MimeTypeException;
-import org.apache.tika.mime.MimeTypes;
 import org.springframework.web.multipart.MultipartFile;
 
 public class FileTypeDetector {
 
     private static final Tika tika = new Tika();
 
-    public static String detectFileType(byte[] fileBytes) {
-        try {
-            // 파일의 MIME 타입 추출
-            String mimeType = tika.detect(fileBytes);
+    public static String detectFileTypeFromMultipartFile(MultipartFile file) {
+        try (InputStream inputStream = file.getInputStream()) {
+            // 파일을 한 번에 메모리에 로드하지 않고 스트리밍 방식으로 MIME 타입 감지
+            String mimeType = tika.detect(inputStream);
 
             if (mimeType.startsWith("image/")) {
                 return "IMAGE";
@@ -22,18 +23,8 @@ public static String detectFileType(byte[] fileBytes) {
             } else {
                 return "UNKNOWN";
             }
-        } catch (Exception e) {
-            throw new RuntimeException("파일 타입 분석 중 오류 발생: " + e.getMessage(), e);
-        }
-    }
-
-    public static String detectFileTypeFromMultipartFile(MultipartFile file) {
-        try {
-            // MultipartFile로부터 바이트 배열 추출
-            return detectFileType(file.getBytes());
         } catch (IOException e) {
-            throw new RuntimeException("파일 분석 중 오류 발생: " + e.getMessage(), e);
+            throw new CustomException(ErrorCode.UNSUPPORTED_FILE_TYPE.getCode(), ErrorCode.UNSUPPORTED_FILE_TYPE.getMsg());
         }
     }
 }
-
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/S3Service.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/S3Service.java
index 3860a5d1..ce5132f8 100644
--- a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/S3Service.java
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/service/S3Service.java
@@ -1,17 +1,23 @@
 package com.jootalkpia.file_server.service;
 
+import com.jootalkpia.file_server.exception.common.CustomException;
+import com.jootalkpia.file_server.exception.common.ErrorCode;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Service;
 import org.springframework.web.multipart.MultipartFile;
+import software.amazon.awssdk.core.ResponseInputStream;
+import software.amazon.awssdk.core.exception.SdkClientException;
 import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectResponse;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
 import software.amazon.awssdk.services.s3.model.PutObjectRequest;
 
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Path;
-
 @Service
 @Slf4j
 @RequiredArgsConstructor
@@ -21,28 +27,19 @@ public class S3Service {
 
     @Value("${spring.cloud.aws.s3.bucket}")
     private String bucketName;
+    @Value("${spring.cloud.aws.region.static}")
+    private String region;
 
-    public String uploadFile(MultipartFile file, String fileType, Long fileId) {
+    public String uploadFile(MultipartFile file, String folder, Long fileId) {
         Path tempFile = null;
         try {
-            // 폴더 경로 설정
-            String folder;
-            if ("IMAGE".equalsIgnoreCase(fileType)) {
-                folder = "images/";
-            } else if ("VIDEO".equalsIgnoreCase(fileType)) {
-                folder = "videos/";
-            } else if ("THUMBNAIL".equalsIgnoreCase(fileType)) {
-                folder = "thumbnails/";
-            } else {
-                throw new IllegalArgumentException("Unsupported file type: " + fileType);
-            }
 
             // S3에 저장될 파일 키 생성
             String key = folder + fileId;
 
             // 임시 파일 생성
             tempFile = Files.createTempFile("temp-", ".tmp");
-            file.transferTo(tempFile.toFile()); // MultipartFile -> 임시 파일 저장
+            file.transferTo(tempFile.toFile());
 
             // S3에 업로드
             s3Client.putObject(
@@ -53,13 +50,23 @@ public String uploadFile(MultipartFile file, String fileType, Long fileId) {
                             .build(),
                     tempFile);
 
-            log.info("파일 업로드 완료 - S3 Key: {}", key);
-            return "https://" + bucketName + ".s3.amazonaws.com/" + key;
+            log.info("파일 업로드 완료 - S3 Key: {}", "https://" + bucketName +".s3"+region+".amazonaws.com/" + key);
+            return "https://" + bucketName +".s3"+region+".amazonaws.com/" + key;
 
         } catch (IOException e) {
-            log.error("파일 업로드 중 오류 발생: {}", e.getMessage(), e);
-            throw new RuntimeException("파일 업로드 중 오류가 발생했습니다.");
-        } finally {
+            log.error("파일 업로드 중 IOException 발생: {}", e.getMessage(), e);
+            throw new CustomException(ErrorCode.IMAGE_UPLOAD_FAILED.getCode(), ErrorCode.IMAGE_UPLOAD_FAILED.getMsg());
+
+        } catch (SdkClientException e) {
+            log.error("S3 클라이언트 예외 발생: {}", e.getMessage(), e);
+            throw new CustomException(ErrorCode.IMAGE_UPLOAD_FAILED.getCode(), "S3 클라이언트 오류 발생");
+
+        } catch (Exception e) {
+            log.error("알 수 없는 오류 발생: {}", e.getMessage(), e);
+            throw new CustomException(ErrorCode.UNKNOWN.getCode(), "알 수 없는 오류 발생");
+
+        }
+        finally {
             // 임시 파일 삭제
             try {
                 if (tempFile != null && Files.exists(tempFile)) {
@@ -71,4 +78,28 @@ public String uploadFile(MultipartFile file, String fileType, Long fileId) {
             }
         }
     }
+
+    public ResponseInputStream<GetObjectResponse> downloadFile(String folder, Long fileId) {
+        String key = folder + "/" + fileId;
+
+        try {
+            return s3Client.getObject(
+                    GetObjectRequest.builder()
+                            .bucket(bucketName)
+                            .key(key)
+                            .build());
+
+        } catch (NoSuchKeyException e) {
+            log.error("S3에서 파일을 찾을 수 없음: key={}", key, e);
+            throw new CustomException(ErrorCode.FILE_NOT_FOUND.getCode(), ErrorCode.FILE_NOT_FOUND.getMsg());
+
+        } catch (SdkClientException e) {
+            log.error("S3 클라이언트 오류 발생: key={}, 오류={}", key, e.getMessage(), e);
+            throw new CustomException(ErrorCode.IMAGE_DOWNLOAD_FAILED.getCode(), ErrorCode.IMAGE_DOWNLOAD_FAILED.getMsg());
+
+        } catch (Exception e) {
+            log.error("S3 파일 다운로드 중 오류 발생 - key: {}, 오류: {}", key, e.getMessage(), e);
+            throw new CustomException(ErrorCode.IMAGE_DOWNLOAD_FAILED.getCode(), ErrorCode.IMAGE_DOWNLOAD_FAILED.getMsg());
+        }
+    }
 }
diff --git a/src/backend/file_server/src/main/java/com/jootalkpia/file_server/utils/ValidationUtils.java b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/utils/ValidationUtils.java
new file mode 100644
index 00000000..1e3e808a
--- /dev/null
+++ b/src/backend/file_server/src/main/java/com/jootalkpia/file_server/utils/ValidationUtils.java
@@ -0,0 +1,48 @@
+package com.jootalkpia.file_server.utils;
+
+import com.jootalkpia.file_server.exception.common.CustomException;
+import com.jootalkpia.file_server.exception.common.ErrorCode;
+import lombok.AllArgsConstructor;
+import org.springframework.stereotype.Component;
+import org.springframework.web.multipart.MultipartFile;
+
+@Component
+@AllArgsConstructor
+public class ValidationUtils {
+
+    public static void validateWorkSpaceId(Long workSpaceId) {
+        if (workSpaceId == null || workSpaceId <= 0) {
+            throw new CustomException(ErrorCode.INVALID_PARAMETER.getCode(), ErrorCode.INVALID_PARAMETER.getMsg());
+        }
+    }
+
+    public static void validateChannelId(Long channelId) {
+        if (channelId == null || channelId <= 0) {
+            throw new CustomException(ErrorCode.INVALID_PARAMETER.getCode(), ErrorCode.INVALID_PARAMETER.getMsg());
+        }
+    }
+
+    public static void validateFileId(Long fileId) {
+        if (fileId == null || fileId <= 0) {
+            throw new CustomException(ErrorCode.INVALID_PARAMETER.getCode(), ErrorCode.INVALID_PARAMETER.getMsg());
+        }
+    }
+
+    public static void validateFiles(MultipartFile[] files) {
+        if (files == null || files.length == 0) {
+            throw new CustomException(ErrorCode.MISSING_FILES.getCode(), ErrorCode.MISSING_FILES.getMsg());
+        }
+    }
+
+    public static void validateFile(MultipartFile file) {
+        if (file == null || file.isEmpty()) {
+            throw new CustomException(ErrorCode.MISSING_FILES.getCode(), ErrorCode.MISSING_FILES.getMsg());
+        }
+    }
+
+    public static void validateLengthOfFilesAndThumbnails(int fileLength, int thumbnailLength) {
+        if (fileLength < thumbnailLength) {
+            throw new CustomException(ErrorCode.INVALID_PARAMETER.getCode(), ErrorCode.INVALID_PARAMETER.getMsg());
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/backend/file_server/src/main/resources/application.yml b/src/backend/file_server/src/main/resources/application.yml
index e0c8d3fe..5ff2ff7b 100644
--- a/src/backend/file_server/src/main/resources/application.yml
+++ b/src/backend/file_server/src/main/resources/application.yml
@@ -1,5 +1,5 @@
 server:
-  port: 8080
+  port: ${FILE_PORT}
   tomcat:
     max-swallow-size: -1
 spring: