diff --git a/backintime-websocket/client/build.gradle.kts b/backintime-websocket/client/build.gradle.kts
new file mode 100644
index 00000000..9078cb4b
--- /dev/null
+++ b/backintime-websocket/client/build.gradle.kts
@@ -0,0 +1,30 @@
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+    alias(libs.plugins.androidLibrary)
+}
+
+kotlin {
+    jvm()
+    androidTarget()
+
+    iosX64()
+    iosArm64()
+    iosSimulatorArm64()
+
+    jvmToolchain(17)
+
+    sourceSets {
+        commonMain.dependencies {
+            implementation(project(":backintime-websocket:event"))
+            implementation(libs.ktor.client.core)
+            implementation(libs.ktor.client.cio)
+            implementation(libs.ktor.client.websockets)
+            implementation(libs.ktor.serialization.kotlinx.json)
+        }
+    }
+}
+
+android {
+    namespace = "com.github.kitakkun.backintime.websocket.client"
+    compileSdk = 34
+}
diff --git a/backintime-websocket/client/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/client/BackInTimeWebSocketClient.kt b/backintime-websocket/client/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/client/BackInTimeWebSocketClient.kt
new file mode 100644
index 00000000..da18ed64
--- /dev/null
+++ b/backintime-websocket/client/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/client/BackInTimeWebSocketClient.kt
@@ -0,0 +1,75 @@
+package com.github.kitakkun.backintime.websocket.client
+
+import com.github.kitakkun.backintime.websocket.event.AppToDebuggerEvent
+import com.github.kitakkun.backintime.websocket.event.DebuggerToAppEvent
+import io.ktor.client.HttpClient
+import io.ktor.client.plugins.websocket.DefaultClientWebSocketSession
+import io.ktor.client.plugins.websocket.WebSockets
+import io.ktor.client.plugins.websocket.webSocket
+import io.ktor.serialization.kotlinx.KotlinxWebsocketSerializationConverter
+import io.ktor.websocket.Frame
+import io.ktor.websocket.close
+import io.ktor.websocket.readText
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.IO
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.flow.consumeAsFlow
+import kotlinx.coroutines.flow.filterIsInstance
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.launch
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import kotlin.coroutines.CoroutineContext
+
+class BackInTimeWebSocketClient : CoroutineScope {
+    override val coroutineContext: CoroutineContext = Dispatchers.IO + SupervisorJob()
+
+    private val client = HttpClient {
+        install(WebSockets) {
+            maxFrameSize = Long.MAX_VALUE
+            contentConverter = KotlinxWebsocketSerializationConverter(Json)
+        }
+    }
+
+    private var session: DefaultClientWebSocketSession? = null
+    val connected: Boolean get() = session != null
+
+    private val mutableReceivedEventFlow = MutableSharedFlow<DebuggerToAppEvent>()
+    val receivedEventFlow = mutableReceivedEventFlow.asSharedFlow()
+
+    fun connect(host: String, port: Int) {
+        launch {
+            client.webSocket(
+                host = host,
+                port = port,
+                path = "/backintime",
+            ) {
+                session = this
+
+                incoming
+                    .consumeAsFlow()
+                    .filterIsInstance<Frame.Text>()
+                    .map { Json.decodeFromString<DebuggerToAppEvent>(it.readText()) }
+                    .collect {
+                        mutableReceivedEventFlow.emit(it)
+                    }
+            }
+        }
+    }
+
+    fun send(event: AppToDebuggerEvent) {
+        launch {
+            session?.outgoing?.send(Frame.Text(Json.encodeToString(event)))
+        }
+    }
+
+    fun close() {
+        launch {
+            session?.close()
+        }
+        session = null
+    }
+}
diff --git a/backintime-websocket/event/build.gradle.kts b/backintime-websocket/event/build.gradle.kts
new file mode 100644
index 00000000..c898682b
--- /dev/null
+++ b/backintime-websocket/event/build.gradle.kts
@@ -0,0 +1,27 @@
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+    alias(libs.plugins.kotlinSerialization)
+    alias(libs.plugins.androidLibrary)
+}
+
+kotlin {
+    jvm()
+    androidTarget()
+
+    iosX64()
+    iosArm64()
+    iosSimulatorArm64()
+
+    jvmToolchain(17)
+
+    sourceSets {
+        commonMain.dependencies {
+            implementation(libs.kotlinx.serialization.json)
+        }
+    }
+}
+
+android {
+    namespace = "com.github.kitakkun.backintime.websocket.event"
+    compileSdk = 34
+}
diff --git a/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/AppToDebuggerEvent.kt b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/AppToDebuggerEvent.kt
new file mode 100644
index 00000000..4ef98a32
--- /dev/null
+++ b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/AppToDebuggerEvent.kt
@@ -0,0 +1,45 @@
+package com.github.kitakkun.backintime.websocket.event
+
+import com.github.kitakkun.backintime.websocket.event.model.MethodInfo
+import com.github.kitakkun.backintime.websocket.event.model.PropertyInfo
+import kotlinx.serialization.Serializable
+
+@Serializable
+sealed interface AppToDebuggerEvent {
+    @Serializable
+    data object Ping : AppToDebuggerEvent
+
+    @Serializable
+    data class RegisterInstance(
+        val instanceId: String,
+        val className: String,
+    ) : AppToDebuggerEvent
+
+    @Serializable
+    data class RegisterClassInfo(
+        val className: String,
+        val superClassName: String,
+        val methods: List<MethodInfo>,
+        val properties: List<PropertyInfo>,
+    ) : AppToDebuggerEvent
+
+    @Serializable
+    data class MethodCall(
+        val instanceId: String,
+        val methodName: String,
+        val arguments: List<String>,
+    ) : AppToDebuggerEvent
+
+    @Serializable
+    data class UpdatePropertyValue(
+        val instanceId: String,
+        val propertyName: String,
+        val newValue: String,
+    ) : AppToDebuggerEvent
+
+    @Serializable
+    data class UpdateInstanceState(
+        val instanceId: String,
+        val alive: Boolean,
+    ) : AppToDebuggerEvent
+}
diff --git a/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/DebuggerToAppEvent.kt b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/DebuggerToAppEvent.kt
new file mode 100644
index 00000000..b3aaf751
--- /dev/null
+++ b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/DebuggerToAppEvent.kt
@@ -0,0 +1,20 @@
+package com.github.kitakkun.backintime.websocket.event
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+sealed interface DebuggerToAppEvent {
+    @Serializable
+    data object Ping : DebuggerToAppEvent
+
+    @Serializable
+    data class ForceSetProperty(
+        val propertyName: String,
+        val jsonValue: String,
+    ) : DebuggerToAppEvent
+
+    @Serializable
+    data class RequestGetInstanceState(
+        val instanceIds: List<String>,
+    ) : DebuggerToAppEvent
+}
diff --git a/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/model/MethodInfo.kt b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/model/MethodInfo.kt
new file mode 100644
index 00000000..460423cc
--- /dev/null
+++ b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/model/MethodInfo.kt
@@ -0,0 +1,10 @@
+package com.github.kitakkun.backintime.websocket.event.model
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class MethodInfo(
+    val name: String,
+    val arguments: Map<String, String>,
+    val returnType: String,
+)
diff --git a/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/model/PropertyInfo.kt b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/model/PropertyInfo.kt
new file mode 100644
index 00000000..af0812c6
--- /dev/null
+++ b/backintime-websocket/event/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/event/model/PropertyInfo.kt
@@ -0,0 +1,11 @@
+package com.github.kitakkun.backintime.websocket.event.model
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PropertyInfo(
+    val name: String,
+    val type: String,
+    val valueType: String,
+    val isNullable: Boolean,
+)
diff --git a/backintime-websocket/server/build.gradle.kts b/backintime-websocket/server/build.gradle.kts
new file mode 100644
index 00000000..61831b86
--- /dev/null
+++ b/backintime-websocket/server/build.gradle.kts
@@ -0,0 +1,31 @@
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+    alias(libs.plugins.androidLibrary)
+}
+
+kotlin {
+    jvm()
+    androidTarget()
+
+    iosArm64()
+    iosX64()
+    iosSimulatorArm64()
+
+    jvmToolchain(17)
+
+    sourceSets {
+        commonMain.dependencies {
+            implementation(project(":backintime-websocket:event"))
+            implementation(libs.kotlinx.coroutines.core)
+            implementation(libs.ktor.server.cio)
+            implementation(libs.ktor.server.websockets)
+            implementation(libs.ktor.serialization.kotlinx.json)
+            implementation(libs.uuid)
+        }
+    }
+}
+
+android {
+    namespace = "com.github.kitakkun.backintime.websocket.server"
+    compileSdk = 34
+}
diff --git a/backintime-websocket/server/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/server/BackInTimeWebSocketServer.kt b/backintime-websocket/server/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/server/BackInTimeWebSocketServer.kt
new file mode 100644
index 00000000..721189ca
--- /dev/null
+++ b/backintime-websocket/server/src/commonMain/kotlin/com/github/kitakkun/backintime/websocket/server/BackInTimeWebSocketServer.kt
@@ -0,0 +1,95 @@
+package com.github.kitakkun.backintime.websocket.server
+
+import com.benasher44.uuid.uuid4
+import com.github.kitakkun.backintime.websocket.event.AppToDebuggerEvent
+import com.github.kitakkun.backintime.websocket.event.DebuggerToAppEvent
+import io.ktor.server.application.install
+import io.ktor.server.cio.CIO
+import io.ktor.server.engine.ApplicationEngine
+import io.ktor.server.engine.embeddedServer
+import io.ktor.server.routing.routing
+import io.ktor.server.websocket.DefaultWebSocketServerSession
+import io.ktor.server.websocket.WebSockets
+import io.ktor.server.websocket.webSocket
+import io.ktor.websocket.Frame
+import io.ktor.websocket.readText
+import io.ktor.websocket.send
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.IO
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.flow.consumeAsFlow
+import kotlinx.coroutines.flow.filterIsInstance
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import kotlin.coroutines.CoroutineContext
+
+data class Connection(
+    val session: DefaultWebSocketServerSession,
+    val id: String = uuid4().toString(),
+)
+
+class BackInTimeWebSocketServer : CoroutineScope {
+    override val coroutineContext: CoroutineContext = Dispatchers.IO + SupervisorJob()
+    private var server: ApplicationEngine? = null
+
+    suspend fun getActualPort() = server?.resolvedConnectors()?.firstOrNull()?.port
+    suspend fun getActualHost() = server?.resolvedConnectors()?.firstOrNull()?.host
+
+    val isRunning: Boolean get() = server?.application?.isActive == true
+    private val connections = mutableListOf<Connection>()
+
+    private val mutableConnectionEstablishedFlow = MutableSharedFlow<String>()
+    val connectionEstablishedFlow = mutableConnectionEstablishedFlow.asSharedFlow()
+
+    private val mutableReceivedEventFlow = MutableSharedFlow<Pair<String, AppToDebuggerEvent>>()
+    val receivedEventFlow = mutableReceivedEventFlow.asSharedFlow()
+
+    fun start(port: Int) {
+        server = embeddedServer(
+            factory = CIO,
+            port = port,
+            host = "127.0.0.1",
+        ) {
+            install(WebSockets) {
+                timeoutMillis = 1000 * 60 * 10
+            }
+            routing {
+                webSocket("/backintime") {
+                    val connection = Connection(this)
+                    connections += connection
+
+                    mutableConnectionEstablishedFlow.emit(connection.id)
+
+                    incoming
+                        .consumeAsFlow()
+                        .filterIsInstance<Frame.Text>()
+                        .map { Json.decodeFromString<AppToDebuggerEvent>(it.readText()) }
+                        .collect {
+                            mutableReceivedEventFlow.emit(connection.id to it)
+                        }
+                }
+            }
+        }
+
+        server?.start()
+    }
+
+    fun send(event: DebuggerToAppEvent) {
+        launch {
+            connections.forEach {
+                it.session.send(Json.encodeToString(event))
+            }
+        }
+    }
+
+    fun stop() {
+        server?.stop()
+        server = null
+    }
+}
diff --git a/backintime-websocket/test/build.gradle.kts b/backintime-websocket/test/build.gradle.kts
new file mode 100644
index 00000000..85e0271f
--- /dev/null
+++ b/backintime-websocket/test/build.gradle.kts
@@ -0,0 +1,33 @@
+plugins {
+    alias(libs.plugins.kotlinMultiplatform)
+    alias(libs.plugins.androidLibrary)
+}
+
+kotlin {
+    jvm()
+    androidTarget()
+
+    iosX64()
+    iosArm64()
+    iosSimulatorArm64()
+
+    jvmToolchain(17)
+
+    sourceSets {
+        commonMain.dependencies {
+            implementation(project(":backintime-websocket:event"))
+            implementation(project(":backintime-websocket:server"))
+            implementation(project(":backintime-websocket:client"))
+        }
+
+        commonTest.dependencies {
+            implementation(libs.kotlin.test)
+            implementation(libs.kotlinx.coroutines.test)
+        }
+    }
+}
+
+android {
+    namespace = "com.github.kitakkun.backintime.websocket.test"
+    compileSdk = 34
+}
diff --git a/backintime-websocket/test/src/commonTest/kotlin/com/github/kitakkun/backintime/websocket/test/WebSocketCommunicationTest.kt b/backintime-websocket/test/src/commonTest/kotlin/com/github/kitakkun/backintime/websocket/test/WebSocketCommunicationTest.kt
new file mode 100644
index 00000000..758a3820
--- /dev/null
+++ b/backintime-websocket/test/src/commonTest/kotlin/com/github/kitakkun/backintime/websocket/test/WebSocketCommunicationTest.kt
@@ -0,0 +1,77 @@
+package com.github.kitakkun.backintime.websocket.test
+
+import com.github.kitakkun.backintime.websocket.client.BackInTimeWebSocketClient
+import com.github.kitakkun.backintime.websocket.event.AppToDebuggerEvent
+import com.github.kitakkun.backintime.websocket.event.DebuggerToAppEvent
+import com.github.kitakkun.backintime.websocket.server.BackInTimeWebSocketServer
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+
+class WebSocketCommunicationTest {
+    private val server = BackInTimeWebSocketServer()
+    private val client = BackInTimeWebSocketClient()
+
+    @BeforeTest
+    fun setup() = runBlocking {
+        server.start(0)
+        assertTrue(server.isRunning)
+
+        val host = server.getActualHost()
+        val port = server.getActualPort()
+        assertNotNull(host)
+        assertNotNull(port)
+
+        client.connect(host = host, port = port)
+
+        while (!client.connected) {
+            // Wait for the client to connect
+            delay(500)
+        }
+        assertTrue(client.connected)
+    }
+
+    @AfterTest
+    fun tearDown() {
+        runBlocking {
+            client.close()
+            server.stop()
+        }
+    }
+
+    @Test
+    fun sendEventFromDebuggerToApp() = runBlocking {
+        val collectedEvents = mutableListOf<DebuggerToAppEvent>()
+
+        val job = launch { client.receivedEventFlow.collect(collectedEvents::add) }
+
+        val event = DebuggerToAppEvent.Ping
+        server.send(event)
+        delay(50) // FIXME: This is a hack to wait for the event to be processed
+        job.cancel()
+
+        assertEquals(expected = 1, actual = collectedEvents.size)
+        assertEquals(expected = event, actual = collectedEvents[0])
+    }
+
+    @Test
+    fun sendEventFromAppToDebugger() = runBlocking {
+        val collectedEvents = mutableListOf<AppToDebuggerEvent>()
+
+        val job = launch { server.receivedEventFlow.collect { collectedEvents.add(it.second) } }
+
+        val event = AppToDebuggerEvent.Ping
+        client.send(event)
+        delay(50) // FIXME: This is a hack to wait for the event to be processed
+        job.cancel()
+
+        assertEquals(expected = 1, actual = collectedEvents.size)
+        assertEquals(expected = event, actual = collectedEvents[0])
+    }
+}
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index f3dbb615..5d7cab4e 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -24,6 +24,9 @@ room-runtime = "2.6.1"
 koin-bom = "3.5.0"
 soloader = "0.10.5"
 
+ktor = "2.3.9"
+uuid = "0.8.4"
+
 ktlint-gradle = "12.1.0"
 ktlint = "1.2.1"
 
@@ -73,6 +76,17 @@ koin-bom = { group = "io.insert-koin", name = "koin-bom", version.ref = "koin-bo
 koin-android = { group = "io.insert-koin", name = "koin-android" }
 koin-compose = { group = "io.insert-koin", name = "koin-androidx-compose" }
 
+# ktor server
+ktor-server-cio = { module = "io.ktor:ktor-server-cio", version.ref = "ktor" }
+ktor-server-websockets = { module = "io.ktor:ktor-server-websockets", version.ref = "ktor" }
+ktor-serialization-kotlinx-json = { module = "io.ktor:ktor-serialization-kotlinx-json", version.ref = "ktor" }
+# ktor client
+ktor-client-core = { module = "io.ktor:ktor-client-core", version.ref = "ktor" }
+ktor-client-cio = { module = "io.ktor:ktor-client-cio", version.ref = "ktor" }
+ktor-client-websockets = { module = "io.ktor:ktor-client-websockets", version.ref = "ktor" }
+# multiplatform uuid
+uuid = { module = "com.benasher44:uuid", version.ref = "uuid" }
+
 [plugins]
 # convention
 backintimeLint = { id = "backintime.lint", version = "unspecified" }
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 01c42a7c..24d7dfe5 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -27,5 +27,9 @@ include(
     ":backintime-annotations",
     ":test",
     ":backintime-demo",
-    ":backintime-demo:app"
-)
\ No newline at end of file
+    ":backintime-demo:app",
+    ":backintime-websocket:server",
+    ":backintime-websocket:client",
+    ":backintime-websocket:event",
+    ":backintime-websocket:test",
+)