diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/di/NetworkExtension.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/di/NetworkExtension.kt
index 62034af..73d3773 100644
--- a/core/data-remote/src/main/java/com/kikidan/data_remote/di/NetworkExtension.kt
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/di/NetworkExtension.kt
@@ -9,6 +9,7 @@ import io.ktor.client.plugins.auth.Auth
 import io.ktor.client.plugins.auth.providers.BearerTokens
 import io.ktor.client.plugins.auth.providers.bearer
 import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.plugins.sse.SSE
 import io.ktor.http.ContentType
 import io.ktor.http.contentType
 import io.ktor.serialization.kotlinx.json.json
@@ -30,6 +31,7 @@ internal fun HttpClientConfig<*>.installTodakunDefaults(
         url(baseUrl)
         contentType(ContentType.Application.Json)
     }
+    install(SSE)
     expectSuccess = true
 }
 
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatEntryResponse.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatEntryResponse.kt
new file mode 100644
index 0000000..fa0dcfa
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatEntryResponse.kt
@@ -0,0 +1,24 @@
+package com.kikidan.data_remote.dto.chat
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class ChatEntryResponse(
+    val greeting: String,
+    val suggestions: List<ChatSuggestionResponse> = emptyList(),
+    val quota: ChatQuotaResponse,
+)
+
+@Serializable
+data class ChatSuggestionResponse(
+    val emoji: String,
+    val label: String,
+    val seedPrompt: String,
+    val category: String,
+)
+
+@Serializable
+data class ChatQuotaResponse(
+    val used: Int,
+    val limit: Int,
+)
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatMessageResponse.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatMessageResponse.kt
new file mode 100644
index 0000000..fd73d96
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatMessageResponse.kt
@@ -0,0 +1,21 @@
+package com.kikidan.data_remote.dto.chat
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class ChatMessageResponse(
+    val id: String,
+    val role: String,
+    val content: String,
+    val status: String,
+    val action: ChatActionResponse? = null,
+    val createdAt: String,
+)
+
+@Serializable
+data class ChatActionResponse(
+    val type: String,
+    val label: String,
+    val category: String,
+    val date: String? = null,
+)
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatStreamResponse.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatStreamResponse.kt
new file mode 100644
index 0000000..ce36627
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ChatStreamResponse.kt
@@ -0,0 +1,30 @@
+package com.kikidan.data_remote.dto.chat
+
+import kotlinx.serialization.Serializable
+
+// SSE 이벤트 data payload. 백엔드 이벤트 DTO와 1:1이며 전 필드 non-null이다.
+
+@Serializable
+data class ChatStreamStartResponse(
+    val conversationId: String,
+    val userMessageId: String,
+    val assistantMessageId: String,
+    val quotaUsed: Int,
+    val quotaLimit: Int,
+)
+
+@Serializable
+data class ChatStreamDeltaResponse(
+    val text: String,
+)
+
+@Serializable
+data class ChatStreamDoneResponse(
+    val assistantMessageId: String,
+)
+
+@Serializable
+data class ChatStreamErrorResponse(
+    val code: String,
+    val message: String,
+)
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ConversationDetailResponse.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ConversationDetailResponse.kt
new file mode 100644
index 0000000..f9adb8e
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ConversationDetailResponse.kt
@@ -0,0 +1,10 @@
+package com.kikidan.data_remote.dto.chat
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class ConversationDetailResponse(
+    val id: String,
+    val title: String,
+    val messages: List<ChatMessageResponse> = emptyList(),
+)
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ConversationListResponse.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ConversationListResponse.kt
new file mode 100644
index 0000000..c1fcad7
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/ConversationListResponse.kt
@@ -0,0 +1,16 @@
+package com.kikidan.data_remote.dto.chat
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class ConversationListResponse(
+    val conversations: List<ConversationSummaryResponse> = emptyList(),
+)
+
+@Serializable
+data class ConversationSummaryResponse(
+    val id: String,
+    val title: String,
+    val lastMessageAt: String,
+    val unread: Boolean = false,
+)
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/SendChatMessageRequest.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/SendChatMessageRequest.kt
new file mode 100644
index 0000000..a6b104e
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/dto/chat/SendChatMessageRequest.kt
@@ -0,0 +1,9 @@
+package com.kikidan.data_remote.dto.chat
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class SendChatMessageRequest(
+    val conversationId: String? = null,
+    val content: String,
+)
diff --git a/core/data-remote/src/main/java/com/kikidan/data_remote/sse/ServerSentEvents.kt b/core/data-remote/src/main/java/com/kikidan/data_remote/sse/ServerSentEvents.kt
new file mode 100644
index 0000000..c278f39
--- /dev/null
+++ b/core/data-remote/src/main/java/com/kikidan/data_remote/sse/ServerSentEvents.kt
@@ -0,0 +1,38 @@
+package com.kikidan.data_remote.sse
+
+import io.ktor.client.HttpClient
+import io.ktor.client.plugins.HttpTimeoutConfig
+import io.ktor.client.plugins.sse.sse
+import io.ktor.client.plugins.timeout
+import io.ktor.client.request.HttpRequestBuilder
+import io.ktor.sse.ServerSentEvent
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+
+// 이벤트 간 무응답 상한. 무한으로 두면 서버가 조용히 죽었을 때 앱이 영원히 대기한다.
+private const val SSE_SOCKET_TIMEOUT_MS = 60_000L
+
+/**
+ * SSE 엔드포인트를 열어 서버 이벤트를 Flow로 방출한다.
+ * collect가 취소되면 연결도 닫힌다(sse()의 세션 수명이 곧 이 Flow의 수명). 비-2xx 응답은 collect 시점에 예외로 전파된다.
+ */
+internal fun HttpClient.serverSentEvents(
+    urlString: String,
+    block: HttpRequestBuilder.() -> Unit = {},
+): Flow<ServerSentEvent> =
+    flow {
+        sse(
+            urlString = urlString,
+            request = {
+                block()
+                // 전역 HttpTimeout(requestTimeoutMillis=15s)이 장시간 스트림을 끊으므로 반드시 덮어쓴다.
+                // SSE 전체 길이 상한은 없애고, 소켓 무응답만 60s로 감지한다.
+                timeout {
+                    requestTimeoutMillis = HttpTimeoutConfig.INFINITE_TIMEOUT_MS
+                    socketTimeoutMillis = SSE_SOCKET_TIMEOUT_MS
+                }
+            },
+        ) {
+            incoming.collect { event -> emit(event) }
+        }
+    }