diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index a2cf405..639c779 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -9,8 +9,8 @@
         <option name="gradleJvm" value="#GRADLE_LOCAL_JAVA_HOME" />
         <option name="modules">
           <set>
-            <option value="$PROJECT_DIR$/../../5주차/KUIT6_Android_API" />
-            <option value="$PROJECT_DIR$/../../5주차/KUIT6_Android_API/app" />
+            <option value="$PROJECT_DIR$" />
+            <option value="$PROJECT_DIR$/app" />
           </set>
         </option>
       </GradleProjectSettings>
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 0c6dbbc..92c84d3 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -1,3 +1,5 @@
+import java.util.Properties
+
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.android)
@@ -17,7 +19,13 @@ android {
         versionName = "1.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
-
+        val properties = Properties()
+        val localPropertiesFile = rootProject.file("local.properties")
+        if (localPropertiesFile.exists()) {
+            properties.load(localPropertiesFile.inputStream())
+        }
+        val baseUrl = properties.getProperty("BASE_URL") ?: "http://10.0.2.2:8080/"
+        buildConfigField("String", "BASE_URL", "\"$baseUrl\"")
     }
 
     buildTypes {
@@ -38,6 +46,7 @@ android {
     }
     buildFeatures {
         compose = true
+        buildConfig = true
     }
 }
 
@@ -74,4 +83,9 @@ dependencies {
     androidTestImplementation(libs.androidx.espresso.core)
     debugImplementation(libs.androidx.compose.ui.tooling)
     debugImplementation(libs.androidx.compose.ui.test.manifest)
+
+    implementation(libs.retrofit)
+    implementation(libs.retrofit.converter.gson)
+    implementation(libs.okhttp)
+    implementation(libs.okhttp.logging.interceptor)
 }
diff --git a/app/src/main/java/com/example/kuit6_android_api/data/api/ApiService.kt b/app/src/main/java/com/example/kuit6_android_api/data/api/ApiService.kt
new file mode 100644
index 0000000..dbe79b4
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/data/api/ApiService.kt
@@ -0,0 +1,51 @@
+package com.example.kuit6_android_api.data.api
+
+import com.example.kuit6_android_api.data.model.request.PostCreateRequest
+import com.example.kuit6_android_api.data.model.response.BaseResponse
+import com.example.kuit6_android_api.data.model.response.PostResponse
+import okhttp3.MultipartBody
+import retrofit2.http.Body
+import retrofit2.http.DELETE
+import retrofit2.http.GET
+import retrofit2.http.Multipart
+import retrofit2.http.POST
+import retrofit2.http.PUT
+import retrofit2.http.Part
+import retrofit2.http.Path
+import retrofit2.http.Query
+
+interface ApiService {
+    @GET("/api/posts")
+    suspend fun getPosts(): BaseResponse<List<PostResponse>>
+
+    @POST("/api/posts")
+    suspend fun createPost(
+        @Query("author") author: String = "예원",
+        @Body request: PostCreateRequest
+    ): BaseResponse<PostResponse>
+
+    // DELETE 요청
+    @DELETE("/api/posts/{id}")
+    suspend fun deletePost(
+        @Path("id") id: Long
+    ): BaseResponse<Unit> // data에 빈 객체 반환
+
+    @GET("/api/posts/{id}")
+    suspend fun getPostDetail(
+        @Path("id") id: Long
+    ): BaseResponse<PostResponse>
+
+    // 업데이트 요청
+    @PUT("/api/posts/{id}")
+    suspend fun updatePost(
+        @Path("id") id: Long,
+        @Body request: PostCreateRequest // 수정된 내용 전달
+    ): BaseResponse<PostResponse> // 수정된 내용이 data에 들어가고, 반환
+
+    // Retrofit에서 이미지 파일을 multipart/form-data로 업로드
+    @Multipart // multipart?form-data 형식의 요청을 보냄
+    @POST("/api/images/upload")
+    suspend fun uploadImage(
+        @Part file: MultipartBody.Part // multipart의 한 조각(part) 타입
+    ):BaseResponse<Map<String, String>> // 본문 data가 key-value의 Map 형식 -> ex) "url":"..."
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/kuit6_android_api/data/api/RetrofitClient.kt b/app/src/main/java/com/example/kuit6_android_api/data/api/RetrofitClient.kt
new file mode 100644
index 0000000..897b8b7
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/data/api/RetrofitClient.kt
@@ -0,0 +1,30 @@
+package com.example.kuit6_android_api.data.api
+
+import com.example.kuit6_android_api.BuildConfig
+import okhttp3.OkHttpClient
+import okhttp3.logging.HttpLoggingInterceptor
+import retrofit2.Retrofit
+import retrofit2.converter.gson.GsonConverterFactory
+import java.util.concurrent.TimeUnit
+
+object RetrofitClient {
+
+    private val loggingInterceptor = HttpLoggingInterceptor().apply {
+        level = HttpLoggingInterceptor.Level.BODY
+    }
+
+    private val okHttpClient = OkHttpClient.Builder()
+        .addInterceptor(loggingInterceptor)
+        .connectTimeout(30, TimeUnit.SECONDS)
+        .readTimeout(30, TimeUnit.SECONDS)
+        .writeTimeout(30, TimeUnit.SECONDS)
+        .build()
+
+    private val retrofit: Retrofit = Retrofit.Builder()
+        .baseUrl(BuildConfig.BASE_URL)
+        .client(okHttpClient)
+        .addConverterFactory(GsonConverterFactory.create())
+        .build()
+
+    val apiService: ApiService = retrofit.create(ApiService::class.java)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/kuit6_android_api/data/model/request/PostCreateRequest.kt b/app/src/main/java/com/example/kuit6_android_api/data/model/request/PostCreateRequest.kt
new file mode 100644
index 0000000..5e4e011
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/data/model/request/PostCreateRequest.kt
@@ -0,0 +1,9 @@
+package com.example.kuit6_android_api.data.model.request
+
+import kotlinx.serialization.SerialName
+
+data class PostCreateRequest(
+    @SerialName("title") val title: String,
+    @SerialName("content") val content: String,
+    @SerialName("imageUrl") val imageUrl: String?,
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/kuit6_android_api/data/model/response/AuthorResponse.kt b/app/src/main/java/com/example/kuit6_android_api/data/model/response/AuthorResponse.kt
new file mode 100644
index 0000000..9d55ecd
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/data/model/response/AuthorResponse.kt
@@ -0,0 +1,9 @@
+package com.example.kuit6_android_api.data.model.response
+
+import kotlinx.serialization.SerialName
+
+data class AuthorResponse(
+    @SerialName("id") val id: Long,
+    @SerialName("username") val username: String,
+    @SerialName("profileImageUrl") val profileImageUrl: String?
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/kuit6_android_api/data/model/response/BaseResponse.kt b/app/src/main/java/com/example/kuit6_android_api/data/model/response/BaseResponse.kt
new file mode 100644
index 0000000..cbec036
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/data/model/response/BaseResponse.kt
@@ -0,0 +1,10 @@
+package com.example.kuit6_android_api.data.model.response
+
+import kotlinx.serialization.SerialName
+
+data class BaseResponse<T>(
+    @SerialName("success") val success: Boolean,
+    @SerialName("message") val message: String?,
+    @SerialName("data") val data: T?,
+    @SerialName("timestamp") val timestamp: String
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/kuit6_android_api/data/model/response/PostResponse.kt b/app/src/main/java/com/example/kuit6_android_api/data/model/response/PostResponse.kt
new file mode 100644
index 0000000..64319b1
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/data/model/response/PostResponse.kt
@@ -0,0 +1,13 @@
+package com.example.kuit6_android_api.data.model.response
+
+import kotlinx.serialization.SerialName
+
+data class PostResponse(
+    @SerialName("id") val id: Long,
+    @SerialName("title") val title: String,
+    @SerialName("content") val content: String,
+    @SerialName("imageUrl") val imageUrl: String?,
+    @SerialName("author") val author: AuthorResponse,
+    @SerialName("createdAt") val createdAt: String,
+    @SerialName("updatedAt") val updatedAt: String
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/example/kuit6_android_api/ui/post/component/PostItem.kt b/app/src/main/java/com/example/kuit6_android_api/ui/post/component/PostItem.kt
index df2e5fe..b5344a8 100644
--- a/app/src/main/java/com/example/kuit6_android_api/ui/post/component/PostItem.kt
+++ b/app/src/main/java/com/example/kuit6_android_api/ui/post/component/PostItem.kt
@@ -29,13 +29,13 @@ import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import coil.compose.AsyncImage
-import com.example.kuit6_android_api.data.model.Author
-import com.example.kuit6_android_api.data.model.Post
+import com.example.kuit6_android_api.data.model.response.AuthorResponse
+import com.example.kuit6_android_api.data.model.response.PostResponse
 import com.example.kuit6_android_api.util.formatDateTime
 
 @Composable
 fun PostItem(
-    post: Post,
+    post: PostResponse,
     onClick: () -> Unit
 ) {
     Card(
@@ -153,12 +153,12 @@ fun PostItem(
 fun PostItemPreview() {
     MaterialTheme {
         PostItem(
-            post = Post(
+            post = PostResponse(
                 id = 1,
                 title = "샘플 게시글 제목",
                 content = "이것은 샘플 게시글 내용입니다. 미리보기에서는 두 줄까지만 표시됩니다.",
                 imageUrl = null,
-                author = Author(1, "testuser", null),
+                author = AuthorResponse(1, "testuser", null),
                 createdAt = "2025-10-03T12:00:00",
                 updatedAt = "2025-10-03T12:00:00"
             ),
diff --git a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostCreateScreen.kt b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostCreateScreen.kt
index 57ea2ab..68d7c96 100644
--- a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostCreateScreen.kt
+++ b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostCreateScreen.kt
@@ -5,6 +5,7 @@ import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -12,15 +13,18 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.Icon
@@ -39,10 +43,14 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
+import coil.compose.AsyncImage
 import com.example.kuit6_android_api.ui.post.viewmodel.PostViewModel
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -52,6 +60,7 @@ fun PostCreateScreen(
     onPostCreated: () -> Unit,
     viewModel: PostViewModel = viewModel()
 ) {
+    val context = LocalContext.current
     var author by remember { mutableStateOf("") }
     var title by remember { mutableStateOf("") }
     var content by remember { mutableStateOf("") }
@@ -60,7 +69,20 @@ fun PostCreateScreen(
     val imagePickerLauncher = rememberLauncherForActivityResult(
         contract = ActivityResultContracts.GetContent()
     ) { uri: Uri? ->
-        selectedImageUri = uri
+        uri?.let {
+            selectedImageUri = it
+            // 이미지 선택 시 자동으로 업로드
+            viewModel.uploadImage(
+                context = context,
+                uri = it,
+                onSuccess = { imageUrl ->
+                    // 업로드 성공 처리는 ViewModel에서 자동으로 됨
+                },
+                onError = { error ->
+                    // 에러 처리 (필요시 Toast 등으로 표시)
+                }
+            )
+        }
     }
 
     Scaffold(
@@ -171,7 +193,7 @@ fun PostCreateScreen(
                             color = MaterialTheme.colorScheme.onSurface
                         )
 
-                        if (selectedImageUri == null) {
+                        if (selectedImageUri == null && !viewModel.isUploading) {
                             FilledTonalButton(
                                 onClick = { imagePickerLauncher.launch("image/*") },
                                 shape = RoundedCornerShape(10.dp)
@@ -180,6 +202,68 @@ fun PostCreateScreen(
                             }
                         }
                     }
+
+                    // 업로드 중 표시
+                    if (viewModel.isUploading) {
+                        Spacer(modifier = Modifier.height(16.dp))
+                        Box(
+                            modifier = Modifier.fillMaxWidth(),
+                            contentAlignment = Alignment.Center
+                        ) {
+                            Column(
+                                horizontalAlignment = Alignment.CenterHorizontally
+                            ) {
+                                CircularProgressIndicator(
+                                    modifier = Modifier.size(40.dp)
+                                )
+                                Spacer(modifier = Modifier.height(8.dp))
+                                Text(
+                                    text = "업로드 중...",
+                                    style = MaterialTheme.typography.bodyMedium,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                                )
+                            }
+                        }
+                    }
+
+                    // 이미지 미리보기
+                    if (selectedImageUri != null && viewModel.uploadedImageUrl != null) {
+                        Spacer(modifier = Modifier.height(16.dp))
+                        Box(
+                            modifier = Modifier.fillMaxWidth()
+                        ) {
+                            AsyncImage(
+                                model = selectedImageUri,
+                                contentDescription = "선택된 이미지",
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .height(200.dp)
+                                    .clip(RoundedCornerShape(12.dp)),
+                                contentScale = ContentScale.Crop
+                            )
+
+                            // 삭제 버튼
+                            IconButton(
+                                onClick = {
+                                    selectedImageUri = null
+                                    viewModel.clearUploadedImageUrl()
+                                },
+                                modifier = Modifier
+                                    .align(Alignment.TopEnd)
+                                    .padding(8.dp)
+                                    .background(
+                                        MaterialTheme.colorScheme.surface.copy(alpha = 0.8f),
+                                        RoundedCornerShape(20.dp)
+                                    )
+                            ) {
+                                Icon(
+                                    Icons.Default.Close,
+                                    contentDescription = "이미지 제거",
+                                    tint = MaterialTheme.colorScheme.onSurface
+                                )
+                            }
+                        }
+                    }
                 }
             }
 
@@ -188,14 +272,19 @@ fun PostCreateScreen(
             Button(
                 onClick = {
                     val finalAuthor = author.ifBlank { "anonymous" }
-                    viewModel.createPost(finalAuthor, title, content, null) {
+                    viewModel.createPost(
+                        author = finalAuthor,
+                        title = title,
+                        content = content,
+                        imageUrl = viewModel.uploadedImageUrl
+                    ) {
                         onPostCreated()
                     }
                 },
                 modifier = Modifier
                     .fillMaxWidth()
                     .height(56.dp),
-                enabled = title.isNotBlank() && content.isNotBlank(),
+                enabled = title.isNotBlank() && content.isNotBlank() && !viewModel.isUploading,
                 shape = RoundedCornerShape(16.dp),
                 elevation = ButtonDefaults.buttonElevation(
                     defaultElevation = 4.dp,
@@ -208,7 +297,7 @@ fun PostCreateScreen(
                 )
             ) {
                 Text(
-                    "작성하기",
+                    if (viewModel.isUploading) "업로드 중..." else "작성하기",
                     style = MaterialTheme.typography.titleMedium.copy(
                         fontWeight = FontWeight.Bold
                     )
diff --git a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostDetailScreen.kt b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostDetailScreen.kt
index 6635ced..94048c1 100644
--- a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostDetailScreen.kt
+++ b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostDetailScreen.kt
@@ -1,5 +1,6 @@
 package com.example.kuit6_android_api.ui.post.screen
 
+import android.widget.Toast
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -75,7 +76,7 @@ fun PostDetailScreen(
                     IconButton(onClick = { onEditClick(postId) }) {
                         Icon(Icons.Default.Edit, contentDescription = "수정")
                     }
-                    IconButton(onClick = { showDeleteDialog = true }) {
+                    IconButton(onClick = {showDeleteDialog = true }) {
                         Icon(Icons.Default.Delete, contentDescription = "삭제")
                     }
                 }
diff --git a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostEditScreen.kt b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostEditScreen.kt
index 0e5eaca..748b038 100644
--- a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostEditScreen.kt
+++ b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostEditScreen.kt
@@ -30,9 +30,9 @@ import androidx.compose.material3.OutlinedTextFieldDefaults
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
-import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -40,7 +40,9 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import coil.compose.AsyncImage
@@ -54,8 +56,8 @@ fun PostEditScreen(
     onPostUpdated: () -> Unit,
     viewModel: PostViewModel = viewModel()
 ) {
-    val post = viewModel.postDetail
-
+    val post by remember { derivedStateOf { viewModel.postDetail } }
+    val context = LocalContext.current
     var title by remember { mutableStateOf("") }
     var content by remember { mutableStateOf("") }
     var selectedImageUri by remember { mutableStateOf<Uri?>(null) }
@@ -64,7 +66,15 @@ fun PostEditScreen(
     val imagePickerLauncher = rememberLauncherForActivityResult(
         contract = ActivityResultContracts.GetContent()
     ) { uri: Uri? ->
-        selectedImageUri = uri
+        uri?.let {
+            selectedImageUri = it
+            viewModel.uploadImage(
+                context = context,
+                uri = it,
+                onSuccess = { /* 업로드 성공 시 uploadedImageUrl 갱신됨 */ },
+                onError = { /* 에러 처리 */ }
+            )
+        }
     }
 
     LaunchedEffect(postId) {
@@ -72,13 +82,16 @@ fun PostEditScreen(
     }
 
     LaunchedEffect(post) {
-        if (post != null && !isLoaded) {
-            title = post.title
-            content = post.content
+        val currentPost = post
+        if (currentPost != null && !isLoaded) {
+            title = currentPost.title
+            content = currentPost.content
             isLoaded = true
         }
     }
 
+    val imageUrl = viewModel.uploadedImageUrl ?: post?.imageUrl
+
     Scaffold(
         topBar = {
             TopAppBar(
@@ -151,14 +164,14 @@ fun PostEditScreen(
 
                 Spacer(modifier = Modifier.height(12.dp))
 
-                if (selectedImageUri != null || post.imageUrl != null) {
+                if (selectedImageUri != null || post?.imageUrl != null) {
                     Box(
                         modifier = Modifier
                             .fillMaxWidth()
                             .height(200.dp)
                     ) {
                         AsyncImage(
-                            model = selectedImageUri ?: post.imageUrl,
+                            model = selectedImageUri ?: post?.imageUrl,
                             contentDescription = "선택된 이미지",
                             modifier = Modifier
                                 .fillMaxWidth()
@@ -171,7 +184,10 @@ fun PostEditScreen(
                             contentScale = ContentScale.Crop
                         )
                         IconButton(
-                            onClick = { selectedImageUri = null },
+                            onClick = { selectedImageUri = null
+                                        viewModel.clearUploadedImageUrl()
+                                        viewModel.clearPostImage()
+                                      },
                             modifier = Modifier
                                 .align(Alignment.TopEnd)
                                 .padding(8.dp)
@@ -202,7 +218,7 @@ fun PostEditScreen(
 
                 Button(
                     onClick = {
-                        viewModel.updatePost(postId, title, content, null) {
+                        viewModel.updatePost(postId, title, content, imageUrl) {
                             onPostUpdated()
                         }
                     },
diff --git a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostListScreen.kt b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostListScreen.kt
index 8522d79..e794d07 100644
--- a/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostListScreen.kt
+++ b/app/src/main/java/com/example/kuit6_android_api/ui/post/screen/PostListScreen.kt
@@ -23,7 +23,8 @@ import androidx.compose.ui.unit.dp
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.example.kuit6_android_api.ui.post.component.PostItem
 import com.example.kuit6_android_api.ui.post.viewmodel.PostViewModel
-
+import com.example.kuit6_android_api.data.model.response.AuthorResponse
+import com.example.kuit6_android_api.data.model.response.PostResponse
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun PostListScreen(
@@ -33,6 +34,7 @@ fun PostListScreen(
 ) {
     val posts = viewModel.posts
 
+    // 화면이 리컴포즈될 때마다 getPost 실행
     LaunchedEffect(Unit) {
         viewModel.getPosts()
     }
diff --git a/app/src/main/java/com/example/kuit6_android_api/ui/post/viewmodel/PostViewModel.kt b/app/src/main/java/com/example/kuit6_android_api/ui/post/viewmodel/PostViewModel.kt
index 444229c..4f51e2a 100644
--- a/app/src/main/java/com/example/kuit6_android_api/ui/post/viewmodel/PostViewModel.kt
+++ b/app/src/main/java/com/example/kuit6_android_api/ui/post/viewmodel/PostViewModel.kt
@@ -1,72 +1,60 @@
 package com.example.kuit6_android_api.ui.post.viewmodel
 
+import android.content.Context
+import android.net.Uri
+import android.provider.OpenableColumns
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import com.example.kuit6_android_api.data.model.Author
-import com.example.kuit6_android_api.data.model.Post
-import kotlinx.coroutines.delay
+import com.example.kuit6_android_api.data.api.RetrofitClient
+import com.example.kuit6_android_api.data.model.request.PostCreateRequest
+import com.example.kuit6_android_api.data.model.response.PostResponse
 import kotlinx.coroutines.launch
+import okhttp3.MediaType.Companion.toMediaTypeOrNull
+import okhttp3.MultipartBody
+import okhttp3.RequestBody.Companion.asRequestBody
+import java.io.File
+import java.io.FileOutputStream
 import java.time.LocalDateTime
 
 class PostViewModel : ViewModel() {
 
-    // 더미 데이터
-    private val dummyPosts = mutableStateListOf(
-        Post(
-            id = 1,
-            title = "Jetpack Compose 시작하기",
-            content = "Jetpack Compose는 Android의 최신 UI 툴킷입니다. 선언형 UI로 더 쉽고 빠르게 UI를 만들 수 있습니다.",
-            imageUrl = null,
-            author = Author(1, "개발자A", null),
-            createdAt = "2025-10-05T10:00:00",
-            updatedAt = "2025-10-05T10:00:00"
-        ),
-        Post(
-            id = 2,
-            title = "Kotlin Coroutines 완벽 가이드",
-            content = "비동기 프로그래밍을 쉽게! Coroutines를 사용하면 복잡한 비동기 코드를 간단하게 작성할 수 있습니다.",
-            imageUrl = null,
-            author = Author(2, "개발자B", null),
-            createdAt = "2025-10-05T11:30:00",
-            updatedAt = "2025-10-05T11:30:00"
-        ),
-        Post(
-            id = 3,
-            title = "Android MVVM 아키텍처",
-            content = "MVVM 패턴으로 코드를 구조화하면 테스트와 유지보수가 쉬워집니다. ViewModel과 LiveData/StateFlow를 활용해봅시다.",
-            imageUrl = null,
-            author = Author(1, "개발자A", null),
-            createdAt = "2025-10-05T14:20:00",
-            updatedAt = "2025-10-05T14:20:00"
-        )
-    )
-
     private var nextId = 4L
 
-    var posts by mutableStateOf<List<Post>>(emptyList())
+    var posts by mutableStateOf<List<PostResponse>>(emptyList())
         private set
 
-    var postDetail by mutableStateOf<Post?>(null)
+    var postDetail by mutableStateOf<PostResponse?>(null)
         private set
 
     var uploadedImageUrl by mutableStateOf<String?>(null)
         private set
 
+    var isUploading by mutableStateOf(false)
+        private set
+
+    private val apiService = RetrofitClient.apiService
     fun getPosts() {
-        viewModelScope.launch {
-            delay(500) // 네트워크 시뮬레이션
-            posts = dummyPosts.toList()
+        viewModelScope.launch{
+            runCatching {
+                apiService.getPosts()
+            }.onSuccess { response ->
+                if(response.success && response.data != null)
+                    posts = response.data
+            }
         }
     }
 
     fun getPostDetail(postId: Long) {
         viewModelScope.launch {
-            delay(300)
-            postDetail = dummyPosts.find { it.id == postId }
+            runCatching {
+                apiService.getPostDetail(postId)
+            }.onSuccess { response ->
+                if(response.success && response.data != null)
+                    postDetail = response.data
+            }
         }
     }
 
@@ -78,22 +66,21 @@ class PostViewModel : ViewModel() {
         onSuccess: () -> Unit = {}
     ) {
         viewModelScope.launch {
-            delay(500)
-            val newPost = Post(
-                id = nextId++,
-                title = title,
-                content = content,
-                imageUrl = imageUrl,
-                author = Author(nextId, author, null),
-                createdAt = getCurrentDateTime(),
-                updatedAt = getCurrentDateTime()
-            )
-            dummyPosts.add(0, newPost)
-            posts = dummyPosts.toList()
-            onSuccess()
+            runCatching {
+                val finalImageUrl = imageUrl ?: uploadedImageUrl
+                val request = PostCreateRequest(title, content, finalImageUrl)
+                apiService.createPost(author, request)
+            }.onSuccess { response ->
+                if (response.success) {
+                    // 이미지 업로드 관련 코드
+                    clearUploadedImageUrl()
+                    onSuccess()
+                }
+            }
         }
     }
 
+    // 게시물 수정 시 호출
     fun updatePost(
         postId: Long,
         title: String,
@@ -102,37 +89,121 @@ class PostViewModel : ViewModel() {
         onSuccess: () -> Unit = {}
     ) {
         viewModelScope.launch {
-            delay(500)
-            val index = dummyPosts.indexOfFirst { it.id == postId }
-            if (index != -1) {
-                val oldPost = dummyPosts[index]
-                val updatedPost = oldPost.copy(
-                    title = title,
-                    content = content,
-                    imageUrl = imageUrl,
-                    updatedAt = getCurrentDateTime()
-                )
-                dummyPosts[index] = updatedPost
-                postDetail = updatedPost
-                posts = dummyPosts.toList()
-                onSuccess()
+            runCatching {
+                val finalImageUrl = imageUrl ?: uploadedImageUrl // imageUrl이 없으면 uploadImage()에서 정해진 uploadedImageUrl 가져옴
+                // 요청 body로 보낼 DTO 인스턴스 만들기
+                val request = PostCreateRequest(title, content, finalImageUrl)
+                apiService.updatePost(postId, request)
+            }.onSuccess { response ->
+                if(response.success && response.data != null){
+                    // 변경된 새 리스트를 posts에 대입
+                    posts = posts.map{
+                        // 순회 중인 원소의 id == postId면 갱신된 객체 response.data로 교체
+                        if(it.id == postId) response.data else it
+                    }
+                    postDetail = response.data // postDetail을 갱신된 객체로 바꾸기
+                    onSuccess()
+                }
+            }
+        }
+    }
+
+    // 삭제 시 호출
+    fun deletePost(
+        postId: Long,
+        onSuccess: () -> Unit = {}
+    ) {
+        viewModelScope.launch {
+            runCatching {
+                apiService.deletePost(postId)
+            }.onSuccess { response ->
+                if(response.success){
+                    posts = posts.filterNot { it.id == postId }
+                    onSuccess()
+                }
             }
         }
     }
 
-    fun deletePost(postId: Long, onSuccess: () -> Unit = {}) {
+    private fun uriToFile(context: Context, uri: Uri): File? {
+        return try {
+            val contentResolver = context.contentResolver
+            val fileName = getFileName(context, uri) ?: "image_${System.currentTimeMillis()}.jpg"
+            val tempFile = File(context.cacheDir, fileName)
+
+            contentResolver.openInputStream(uri)?.use { input ->
+                FileOutputStream(tempFile).use { output ->
+                    input.copyTo(output)
+                }
+            }
+            tempFile
+        } catch (e: Exception) {
+            e.printStackTrace()
+            null
+        }
+    }
+
+    // URI로부터 파일 이름 가져오기
+    private fun getFileName(context: Context, uri: Uri): String? {
+        var fileName: String? = null
+        val cursor = context.contentResolver.query(uri, null, null, null, null)
+        cursor?.use {
+            if (it.moveToFirst()) {
+                val nameIndex = it.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+                if (nameIndex != -1) {
+                    fileName = it.getString(nameIndex)
+                }
+            }
+        }
+        return fileName
+    }
+
+    // 이미지 업로드 시 호출
+    fun uploadImage(
+        context: Context,
+        uri: Uri,
+        onSuccess: (String) -> Unit = {},
+        onError: (String) -> Unit = {}
+    ) {
         viewModelScope.launch {
-            delay(300)
-            dummyPosts.removeIf { it.id == postId }
-            posts = dummyPosts.toList()
-            onSuccess()
+            isUploading = true
+            runCatching {
+                val file = uriToFile(context, uri) // uri를 실제 파일로 변환
+                if (file == null) {
+                    throw Exception("파일 변환 실패")
+                }
+
+                // 파일 내용을 RequestBody로 감쌈
+                val requestFile = file.asRequestBody("image/*".toMediaTypeOrNull())
+                // Part 생성
+                val body = MultipartBody.Part.createFormData("file", file.name, requestFile)
+
+                apiService.uploadImage(body)
+            }.onSuccess { response ->
+                isUploading = false
+                if (response.success && response.data != null) {
+                    val imageUrl = response.data["imageUrl"]
+                    if (imageUrl != null) {
+                        uploadedImageUrl = imageUrl
+                        onSuccess(imageUrl)
+                    }
+                }
+            }.onFailure { error ->
+                isUploading = false
+                onError(error.message ?: "업로드 실패")
+            }
         }
     }
 
+    //이미지 삭제 버튼 누를 시 호출
     fun clearUploadedImageUrl() {
         uploadedImageUrl = null
     }
 
+    fun clearPostImage() {
+        postDetail = postDetail?.copy(imageUrl = null)
+    }
+
     private fun getCurrentDateTime(): String {
         return LocalDateTime.now().toString()
     }
diff --git a/app/src/main/java/com/example/kuit6_android_api/util/FileUtil.kt b/app/src/main/java/com/example/kuit6_android_api/util/FileUtil.kt
new file mode 100644
index 0000000..c0bf440
--- /dev/null
+++ b/app/src/main/java/com/example/kuit6_android_api/util/FileUtil.kt
@@ -0,0 +1,43 @@
+package com.example.kuit6_android_api.util
+
+import android.content.Context
+import android.net.Uri
+import android.provider.OpenableColumns
+import java.io.File
+import java.io.FileOutputStream
+
+object FileUtil {
+
+    fun getFileFromUri(context: Context, uri: Uri): File? {
+        return try {
+            val fileName = getFileName(context, uri)
+            val tempFile = File(context.cacheDir, fileName)
+
+            context.contentResolver.openInputStream(uri)?.use { inputStream ->
+                FileOutputStream(tempFile).use { outputStream ->
+                    inputStream.copyTo(outputStream)
+                }
+            }
+
+            tempFile
+        } catch (e: Exception) {
+            e.printStackTrace()
+            null
+        }
+    }
+
+    private fun getFileName(context: Context, uri: Uri): String {
+        var fileName = "image_${System.currentTimeMillis()}.jpg"
+
+        context.contentResolver.query(uri, null, null, null, null)?.use { cursor ->
+            if (cursor.moveToFirst()) {
+                val nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+                if (nameIndex != -1) {
+                    fileName = cursor.getString(nameIndex)
+                }
+            }
+        }
+
+        return fileName
+    }
+}
\ No newline at end of file