diff --git a/gradle.properties b/gradle.properties
index 3f32a52..a3293d9 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,2 @@
 kotlin.code.style=official
-ktor_version=2.3.12
-kotlin_version=2.0.10
-logback_version=1.4.14
-kotlinx_html_version=0.10.1
+
diff --git a/src/main/kotlin/Application.kt b/src/main/kotlin/Application.kt
index a062f94..2e98582 100644
--- a/src/main/kotlin/Application.kt
+++ b/src/main/kotlin/Application.kt
@@ -7,10 +7,7 @@ import io.ktor.http.HttpStatusCode
 import io.ktor.serialization.deserialize
 import io.ktor.serialization.kotlinx.KotlinxWebsocketSerializationConverter
 import io.ktor.serialization.kotlinx.json.json
-import io.ktor.server.application.Application
-import io.ktor.server.application.ApplicationCall
-import io.ktor.server.application.call
-import io.ktor.server.application.install
+import io.ktor.server.application.*
 import io.ktor.server.cio.CIO
 import io.ktor.server.engine.embeddedServer
 import io.ktor.server.html.respondHtml
@@ -18,10 +15,15 @@ import io.ktor.server.plugins.contentnegotiation.ContentNegotiation
 import io.ktor.server.plugins.cors.routing.CORS
 import io.ktor.server.plugins.statuspages.StatusPages
 import io.ktor.server.response.respondText
+import io.ktor.server.routing.Route
 import io.ktor.server.routing.get
 import io.ktor.server.routing.routing
 import io.ktor.server.websocket.*
+import kotlinx.coroutines.CoroutineExceptionHandler
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ensureActive
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
@@ -36,10 +38,10 @@ import java.time.Duration
 fun main(args: Array<String>) {
     embeddedServer(CIO, port = 8080) {
         module()
-    }
+    }.start(true)
 }
 
-suspend inline fun ApplicationCall.respondCss(builder: CSSBuilder.() -> Unit) {
+private suspend inline fun ApplicationCall.respondCss(builder: CSSBuilder.() -> Unit) {
     this.respondText(CSSBuilder().apply(builder).toString(), ContentType.Text.CSS)
 }
 
@@ -115,37 +117,54 @@ fun Application.module() {
                 }
             }
         }
+        businessLogic()
+    }
+}
 
-        val mutex = Mutex()
-        val data = mutableMapOf<String, JsonElement>()
-        val outBox = MutableSharedFlow<ServerEvent>()
-        val runner: TaskRunner = TaskRunner.ECHO
+fun Route.businessLogic() {
 
-        webSocket("/ws") { // websocketSession
-            val converter = converter ?: error("Converter is null")
+    val mutex = Mutex()
+    val data = mutableMapOf<String, JsonElement>()
 
-            outBox.onEach {
-                sendSerialized(it)
-            }.launchIn(this)
+    val outBox = MutableSharedFlow<ServerEvent>(100)
 
-            for (frame in incoming) {
-                when (val event: UserEvent = converter.deserialize(frame)) {
-                    is UserDataEvent -> mutex.withLock {
-                        data[event.key] = event.value
+    val runner: TaskRunner = TaskRunner.GROUP_ARGS
+
+    webSocket("/ws") { // websocketSession
+        val converter = converter ?: error("Converter is null")
+
+        //launch sending from outbox in a separate coroutine
+        val sendJob = outBox.onEach {
+            sendSerialized(it)
+        }.catch {
+            application.log.error("Error on send", it)
+        }.launchIn(this)
+
+        for (frame in incoming) {
+            when (val event: UserEvent = converter.deserialize(frame)) {
+                is UserDataEvent -> mutex.withLock {
+                    data[event.key] = event.value
+                }
+
+                is UserStartTaskEvent -> {
+
+                    val snapshot = mutex.withLock {
+                        //                        val snapshot = LinkedHashMap(data)
+                        //                        data.clear()
+                        //                        snapshot
+                        HashMap(data).also { data.clear() }
                     }
 
-                    is UserStartTaskEvent -> launch { //FIXME incorrect scope
-                        mutex.withLock {
-                            val snapshot = HashMap(data)
-                            data.clear()
-                            val taskDef = TaskDefinition(event.taskId, snapshot)
-
+                    application.launch(Dispatchers.Default) {
+                        val taskDef = TaskDefinition(event.taskId, snapshot)
+                        try {
                             val result = runner.runTask(taskDef)
                             val resultEvent = ServerTaskCompleteEvent(taskDef, result)
                             outBox.emit(resultEvent)
+                        } catch (e: Exception) {
+                            outBox.emit(ServerTaskErrorEvent(taskDef, e.message ?: ""))
                         }
                     }
-
                 }
             }
         }
diff --git a/src/main/kotlin/TaskRunner.kt b/src/main/kotlin/TaskRunner.kt
index 6c52a89..0ffca54 100644
--- a/src/main/kotlin/TaskRunner.kt
+++ b/src/main/kotlin/TaskRunner.kt
@@ -1,8 +1,12 @@
 package center.sciprog.ktor.sample
 
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.async
+import kotlinx.coroutines.delay
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.buildJsonObject
+import kotlin.time.Duration.Companion.milliseconds
 
 @Serializable
 data class TaskDefinition(val id: String, val arguments: Map<String, JsonElement>)
@@ -12,12 +16,24 @@ fun interface TaskRunner {
     suspend fun runTask(definition: TaskDefinition): JsonElement
 
     companion object {
-        val ECHO = TaskRunner { definition: TaskDefinition ->
+        val GROUP_ARGS = TaskRunner { definition: TaskDefinition ->
+            delay(100.milliseconds)
             buildJsonObject {
                 definition.arguments.forEach {
                     put(it.key, it.value)
                 }
             }
         }
+
+        fun scopedRunner(scope: CoroutineScope) = TaskRunner { definition ->
+            scope.async {
+                delay(100.milliseconds)
+                buildJsonObject {
+                    definition.arguments.forEach {
+                        put(it.key, it.value)
+                    }
+                }
+            }.await()
+        }
     }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/events.kt b/src/main/kotlin/events.kt
index e634508..38f5391 100644
--- a/src/main/kotlin/events.kt
+++ b/src/main/kotlin/events.kt
@@ -12,8 +12,13 @@ data class UserDataEvent(val key: String, val value: JsonElement) : UserEvent
 @Serializable
 data class UserStartTaskEvent(val taskId: String) : UserEvent
 
+
+
 @Serializable
 sealed interface ServerEvent
 
 @Serializable
-data class ServerTaskCompleteEvent(val taskDefinition: TaskDefinition, val result: JsonElement) : ServerEvent
\ No newline at end of file
+data class ServerTaskCompleteEvent(val taskDefinition: TaskDefinition, val result: JsonElement) : ServerEvent
+
+@Serializable
+data class ServerTaskErrorEvent(val taskDefinition: TaskDefinition, val message: String) : ServerEvent
\ No newline at end of file