diff --git a/.github/workflows/default-ci.yml b/.github/workflows/default-ci.yml
index 3ecf5ea..882c0b2 100644
--- a/.github/workflows/default-ci.yml
+++ b/.github/workflows/default-ci.yml
@@ -11,7 +11,7 @@ jobs:
       - uses: actions/setup-java@v2
         with:
           distribution: 'zulu'
-          java-version: '8'
+          java-version: '17'
       - name: Build with Gradle
         run: ./gradlew :server:build
 
@@ -25,6 +25,6 @@ jobs:
       - uses: actions/setup-java@v2
         with:
           distribution: 'zulu'
-          java-version: '8'
+          java-version: '17'
       - name: Run server tests
         run: ./gradlew :server:test
diff --git a/.github/workflows/on-release.yml b/.github/workflows/on-release.yml
index 0d6f36b..c750b8a 100644
--- a/.github/workflows/on-release.yml
+++ b/.github/workflows/on-release.yml
@@ -11,7 +11,7 @@ jobs:
       - uses: actions/setup-java@v2
         with:
           distribution: 'zulu'
-          java-version: '8'
+          java-version: '17'
       - name: Build with Gradle
         run: ./gradlew :server:build
 
@@ -25,7 +25,7 @@ jobs:
       - uses: actions/setup-java@v2
         with:
           distribution: 'zulu'
-          java-version: '8'
+          java-version: '17'
       - name: Run server tests
         run: ./gradlew :server:test
 
@@ -39,7 +39,7 @@ jobs:
       - uses: actions/setup-java@v2
         with:
           distribution: 'zulu'
-          java-version: '8'
+          java-version: '17'
       - name: Prepare environment
         env:
           GRADLE_PROPERTIES: ${{secrets.GRADLE_PROPERTIES}}
@@ -58,7 +58,7 @@ jobs:
       - uses: actions/setup-java@v2
         with:
           distribution: 'zulu'
-          java-version: '8'
+          java-version: '17'
       - name: Prepare environment
         env:
           GRADLE_PROPERTIES: ${{secrets.GRADLE_PROPERTIES}}
diff --git a/build.gradle.kts b/build.gradle.kts
index 99a5747..19b5bd5 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,14 +1,14 @@
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-    kotlin("jvm") version "1.5.30"
+    kotlin("jvm") version "1.8.20"
     signing
     `maven-publish`
     id("io.github.gradle-nexus.publish-plugin") version "1.0.0"
 }
 
 group = "com.arianegraphql"
-version = "0.0.6"
+version = "0.1.0"
 
 repositories {
     mavenCentral()
@@ -17,9 +17,9 @@ repositories {
 subprojects {
     tasks.withType<KotlinCompile> {
         kotlinOptions {
-            jvmTarget = "1.8"
-            languageVersion = "1.5"
-            apiVersion = "1.5"
+            jvmTarget = "17"
+            languageVersion = "1.8"
+            apiVersion = "1.8"
         }
     }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 7c08e4f..1b298ae 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
\ No newline at end of file
diff --git a/sample/src/main/kotlin/com/arianegraphql/sample/main.kt b/sample/src/main/kotlin/com/arianegraphql/sample/main.kt
index 5461403..9b8c864 100644
--- a/sample/src/main/kotlin/com/arianegraphql/sample/main.kt
+++ b/sample/src/main/kotlin/com/arianegraphql/sample/main.kt
@@ -12,6 +12,7 @@ import com.arianegraphql.server.listener.ServerListener
 import com.arianegraphql.server.listener.SubscriptionListener
 import com.arianegraphql.server.request.HttpRequest
 import graphql.ExecutionInput
+import graphql.GraphQLContext
 import io.ktor.application.*
 import io.ktor.features.*
 import io.ktor.server.engine.*
@@ -74,40 +75,40 @@ fun main() {
                 println("[$sessionId] onNewConnection()")
             }
 
-            override fun onConnected(sessionId: String, context: Any?) {
+            override fun onConnected(sessionId: String, context: GraphQLContext) {
                 println("[$sessionId] onConnected()")
             }
 
-            override fun onStartSubscription(sessionId: String, context: Any?, operationId: String, graphQLRequest: GraphQLRequest) {
+            override fun onStartSubscription(sessionId: String, context: GraphQLContext, operationId: String, graphQLRequest: GraphQLRequest) {
                 println("[$sessionId] onStartSubscription($operationId, ${graphQLRequest.operationName})")
             }
 
-            override fun onStopSubscription(sessionId: String, context: Any?, operationId: String) {
+            override fun onStopSubscription(sessionId: String, context: GraphQLContext, operationId: String) {
                 println("[$sessionId] onStopSubscription($operationId)")
             }
 
-            override fun onCloseConnection(sessionId: String, context: Any?) {
+            override fun onCloseConnection(sessionId: String, context: GraphQLContext) {
                 println("[$sessionId] onCloseConnection()")
             }
         }
 
         resolvers {
             Query {
-                resolve("movies") { _, _: Any?, _: Any?, _ ->
+                resolve("movies") { _, _: Any?, _: GraphQLContext, _ ->
                     movies
                 }
 
-                resolve("directors") { _, _: Any?, _: Any?, _ ->
+                resolve("directors") { _, _: Any?, _: GraphQLContext, _ ->
                     movies.map { it.director }.distinctBy { it.name }
                 }
 
-                resolve("movie") { args, _: Any?, _: Any?, _ ->
+                resolve("movie") { args, _: Any?, _: GraphQLContext, _ ->
                     movies.find { it.title == args["title"] }
                 }
             }
 
             Mutation {
-                resolve("addMovie") { args, parent: Any?, context: Any?, info ->
+                resolve("addMovie") { args, parent: Any?, context: GraphQLContext, info ->
                     val movie = Movie(args["title"], Director(args["director"]))
                     movies.add(movie)
 
@@ -117,7 +118,7 @@ fun main() {
             }
 
             type("Director") {
-                resolve("movies") { args: Any, parent: Director, context: Any?, info ->
+                resolve("movies") { args: Any, parent: Director, context: GraphQLContext, info ->
                     movies.filter { it.director.name == parent.name }
                 }
             }
diff --git a/server-ktor/build.gradle.kts b/server-ktor/build.gradle.kts
index e7050e0..416a37c 100644
--- a/server-ktor/build.gradle.kts
+++ b/server-ktor/build.gradle.kts
@@ -1,11 +1,12 @@
 group = project.rootProject.group
 version = project.rootProject.version
 
-val ktorVersion = "1.6.3"
+val ktorVersion = "2.3.4"
 
 dependencies {
     implementation(project(":server"))
     implementation("io.ktor:ktor-server-cio:$ktorVersion")
-    implementation("io.ktor:ktor-websockets:$ktorVersion")
-    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.12.5")
+    implementation("io.ktor:ktor-server-websockets:$ktorVersion")
+    implementation("io.ktor:ktor-server-cors:$ktorVersion")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.15.2")
 }
diff --git a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerBuilder.kt b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerBuilder.kt
index 973e16e..f5449dd 100644
--- a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerBuilder.kt
+++ b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerBuilder.kt
@@ -4,8 +4,8 @@ import com.arianegraphql.ktx.GraphQLSchemaDslMarker
 import com.arianegraphql.ktx.makeExecutableSchema
 import com.arianegraphql.server.dsl.ArianeServerBuilder
 import graphql.GraphQL
-import io.ktor.application.*
 import java.lang.IllegalStateException
+import io.ktor.server.application.Application
 
 @GraphQLSchemaDslMarker
 class ArianeKtorServerBuilder : ArianeServerBuilder() {
diff --git a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerConfiguration.kt b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerConfiguration.kt
index 371e477..413a298 100644
--- a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerConfiguration.kt
+++ b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/ArianeKtorServerConfiguration.kt
@@ -14,7 +14,7 @@ class ArianeKtorServerConfiguration(
     path: String,
     isPlaygroundEnabled: Boolean,
     enableCORS: Boolean,
-    contextResolver: ContextResolver<*>,
+    contextResolver: ContextResolver,
     serverListener: ServerListener?,
     requestListener: RequestListener?,
     subscriptionListener: SubscriptionListener?,
diff --git a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/KtorPlugin.kt b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/KtorPlugin.kt
index 91faf94..5cc346c 100644
--- a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/KtorPlugin.kt
+++ b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/dsl/KtorPlugin.kt
@@ -1,6 +1,6 @@
 package com.arianegraphql.server.ktor.dsl
 
-import io.ktor.application.*
+import io.ktor.server.application.Application
 
 interface KtorPlugin{
     fun invoke(application: Application)
diff --git a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLRequest.kt b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLRequest.kt
index 567e419..1dd8510 100644
--- a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLRequest.kt
+++ b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLRequest.kt
@@ -2,10 +2,10 @@ package com.arianegraphql.server.ktor
 
 import com.arianegraphql.server.ArianeServer
 import com.arianegraphql.server.request.HttpRequest
-import io.ktor.application.*
+import io.ktor.server.application.*
 import io.ktor.http.*
-import io.ktor.request.*
-import io.ktor.response.*
+import io.ktor.server.request.*
+import io.ktor.server.response.*
 import io.ktor.util.*
 import io.ktor.util.pipeline.*
 
diff --git a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLSubscription.kt b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLSubscription.kt
index 665b9cb..b2ba68a 100644
--- a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLSubscription.kt
+++ b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/handleGraphQLSubscription.kt
@@ -2,12 +2,10 @@ package com.arianegraphql.server.ktor
 
 import com.arianegraphql.server.ArianeServer
 import com.arianegraphql.server.request.WebSocketRequest
-import io.ktor.http.cio.websocket.*
+import io.ktor.server.websocket.*
 import io.ktor.util.*
 import io.ktor.websocket.*
-import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
-import java.lang.Exception
 import java.util.*
 
 suspend fun WebSocketServerSession.handleGraphQLSubscription(arianeServer: ArianeServer) {
diff --git a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/launcher.kt b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/launcher.kt
index 7a5a67e..9e639a6 100644
--- a/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/launcher.kt
+++ b/server-ktor/src/main/kotlin/com/arianegraphql/server/ktor/launcher.kt
@@ -1,16 +1,15 @@
 package com.arianegraphql.server.ktor
 
-import com.arianegraphql.server.config.ArianeServerConfiguration
 import com.arianegraphql.server.config.newArianeServer
 import com.arianegraphql.server.dsl.ArianeServerBuilder
 import com.arianegraphql.server.ktor.dsl.ArianeKtorServerConfiguration
 import com.arianegraphql.server.ktor.dsl.arianeServer
-import io.ktor.application.*
-import io.ktor.features.*
-import io.ktor.routing.*
 import io.ktor.server.cio.*
 import io.ktor.server.engine.*
-import io.ktor.websocket.*
+import io.ktor.server.application.*
+import io.ktor.server.routing.*
+import io.ktor.server.websocket.*
+import io.ktor.server.plugins.cors.routing.CORS
 
 fun ArianeKtorServerConfiguration.launch(wait: Boolean = true) {
     val arianeServer = newArianeServer(JacksonSerializer)
diff --git a/server/build.gradle.kts b/server/build.gradle.kts
index 25be669..f7d07c0 100644
--- a/server/build.gradle.kts
+++ b/server/build.gradle.kts
@@ -2,10 +2,10 @@ group = project.rootProject.group
 version = project.rootProject.version
 
 dependencies {
-    api("com.graphql-java:graphql-java:17.2")
-    api("org.slf4j:slf4j-api:1.7.32")
-    api( "ch.qos.logback:logback-classic:1.2.5")
+    api("com.graphql-java:graphql-java:21.1")
+    api("org.slf4j:slf4j-api:2.0.9")
+    api("ch.qos.logback:logback-classic:1.4.11")
 
-    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.1")
-    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactive:1.5.1")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactive:1.7.3")
 }
\ No newline at end of file
diff --git a/server/src/main/kotlin/com/arianegraphql/ktx/Resolver.kt b/server/src/main/kotlin/com/arianegraphql/ktx/Resolver.kt
index 19035c9..2c6d92a 100644
--- a/server/src/main/kotlin/com/arianegraphql/ktx/Resolver.kt
+++ b/server/src/main/kotlin/com/arianegraphql/ktx/Resolver.kt
@@ -1,26 +1,28 @@
 package com.arianegraphql.ktx
 
+import graphql.GraphQLContext
 import graphql.schema.DataFetcher
 import kotlinx.coroutines.runBlocking
 
-interface Resolver<S, C> {
-    suspend fun resolve(arguments: Argument, source: S, context: C?, info: Info): Any?
+interface Resolver<S> {
+    suspend fun resolve(arguments: Argument, source: S, context: GraphQLContext, info: Info): Any?
 }
 
-@JvmInline value class FunctionalResolver<S, C>(
-    private val lambda: suspend (arguments: Argument, source: S, context: C?, info: Info) -> Any?
-) : Resolver<S, C> {
+@JvmInline value class FunctionalResolver<S>(
+    private val lambda: suspend (arguments: Argument, source: S, context: GraphQLContext, info: Info) -> Any?
+) : Resolver<S> {
 
     override suspend fun resolve(
         arguments: Argument,
         source: S,
-        context: C?,
+        context: GraphQLContext,
         info: Info
     ) = lambda(arguments, source, context, info)
 }
 
-internal fun <S, C> Resolver<S, C>.toDataFetcher(): DataFetcher<Any?> = DataFetcher { env ->
+internal fun <S> Resolver<S>.toDataFetcher(): DataFetcher<Any?> = DataFetcher { env ->
     runBlocking {
-        resolve(DataFetchingArgument(env), env.getSource(), env.getContext(), env)
+        env.graphQlContext
+        resolve(DataFetchingArgument(env), env.getSource(), env.graphQlContext, env)
     }
 }
\ No newline at end of file
diff --git a/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionFilter.kt b/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionFilter.kt
index dbe4f08..1fe51bc 100644
--- a/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionFilter.kt
+++ b/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionFilter.kt
@@ -1,19 +1,21 @@
 package com.arianegraphql.ktx
 
-interface SubscriptionFilter<T, S, C> {
+import graphql.GraphQLContext
 
-    suspend fun test(arguments: Argument, source: S, context: C?, info: Info, item: T): Boolean
+interface SubscriptionFilter<T, S> {
+
+    suspend fun test(arguments: Argument, source: S, context: GraphQLContext, info: Info, item: T): Boolean
 }
 
 @JvmInline
-value class FunctionalSubscriptionFilter<T, S, C>(
-    private val lambda: suspend (arguments: Argument, source: S, context: C?, info: Info, item: T) -> Boolean
-) : SubscriptionFilter<T, S, C> {
+value class FunctionalSubscriptionFilter<T, S>(
+    private val lambda: suspend (arguments: Argument, source: S, context: GraphQLContext, info: Info, item: T) -> Boolean
+) : SubscriptionFilter<T, S> {
 
     override suspend fun test(
         arguments: Argument,
         source: S,
-        context: C?,
+        context: GraphQLContext,
         info: Info,
         item: T
     ) = lambda(arguments, source, context, info, item)
diff --git a/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionTypeResolverBuilder.kt b/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionTypeResolverBuilder.kt
index bfbe0bd..f0a9a23 100644
--- a/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionTypeResolverBuilder.kt
+++ b/server/src/main/kotlin/com/arianegraphql/ktx/SubscriptionTypeResolverBuilder.kt
@@ -1,5 +1,6 @@
 package com.arianegraphql.ktx
 
+import graphql.GraphQLContext
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.reactive.asPublisher
@@ -12,8 +13,8 @@ class SubscriptionTypeResolverBuilder : TypeResolverBuilder() {
 
     fun <T : Any> resolve(field: String, flow: Flow<T>) = resolve(field, flow.asPublisher())
 
-    fun <T : Any, S, C> resolve(field: String, flow: Flow<T>, predicate: SubscriptionFilter<T, S, C>) =
-        resolve(field) { arguments: Argument, source: S, context: C?, info: Info ->
+    fun <T : Any, S> resolve(field: String, flow: Flow<T>, predicate: SubscriptionFilter<T, S>) =
+        resolve(field) { arguments: Argument, source: S, context: GraphQLContext, info: Info ->
             flow.filter {
                 predicate.test(arguments, source, context, info, it)
             }.asPublisher()
@@ -22,6 +23,6 @@ class SubscriptionTypeResolverBuilder : TypeResolverBuilder() {
     fun <T : Any, S, C> resolve(
         field: String,
         flow: Flow<T>,
-        predicate: suspend (arguments: Argument, source: S, context: C?, info: Info, item: T) -> Boolean
+        predicate: suspend (arguments: Argument, source: S, context: GraphQLContext, info: Info, item: T) -> Boolean
     ) = resolve(field, flow, FunctionalSubscriptionFilter(predicate))
 }
\ No newline at end of file
diff --git a/server/src/main/kotlin/com/arianegraphql/ktx/TypeResolverBuilder.kt b/server/src/main/kotlin/com/arianegraphql/ktx/TypeResolverBuilder.kt
index 0ce762a..9419588 100644
--- a/server/src/main/kotlin/com/arianegraphql/ktx/TypeResolverBuilder.kt
+++ b/server/src/main/kotlin/com/arianegraphql/ktx/TypeResolverBuilder.kt
@@ -1,17 +1,18 @@
 package com.arianegraphql.ktx
 
+import graphql.GraphQLContext
 import graphql.schema.idl.TypeRuntimeWiring
 
 @GraphQLSchemaDslMarker
 open class TypeResolverBuilder {
 
-    internal val typeResolver = mutableMapOf<String, Resolver<*, *>>()
+    internal val typeResolver = mutableMapOf<String, Resolver<*>>()
 
-    fun <S, C> resolve(field: String, resolver: Resolver<S, C>) {
+    fun <S> resolve(field: String, resolver: Resolver<S>) {
         typeResolver[field] = resolver
     }
 
-    fun <S, C> resolve(field: String, resolver: suspend (arguments: Argument, source: S, context: C?, info: Info) -> Any?) {
+    fun <S> resolve(field: String, resolver: suspend (arguments: Argument, source: S, context: GraphQLContext, info: Info) -> Any?) {
         typeResolver[field] = FunctionalResolver(resolver)
     }
 
diff --git a/server/src/main/kotlin/com/arianegraphql/server/ArianeServerImpl.kt b/server/src/main/kotlin/com/arianegraphql/server/ArianeServerImpl.kt
index 206303e..9de6580 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/ArianeServerImpl.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/ArianeServerImpl.kt
@@ -17,7 +17,7 @@ import kotlinx.coroutines.flow.*
 class ArianeServerImpl(
     private val schema: GraphQL,
     private val isPlaygroundEnabled: Boolean,
-    private val contextResolver: ContextResolver<*>,
+    private val contextResolver: ContextResolver,
     private val requestListener: RequestListener?,
     private val subscriptionListener: SubscriptionListener?,
     jsonSerializer: JsonSerializer,
diff --git a/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandler.kt b/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandler.kt
index 3fc17a9..026e636 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandler.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandler.kt
@@ -6,7 +6,7 @@ import com.arianegraphql.server.request.WebSocketRequest
 import kotlinx.coroutines.flow.Flow
 
 interface SubscriptionHandler {
-    suspend fun initSubscription(wsRequest: WebSocketRequest, contextResolver: ContextResolver<*>): Flow<String>
+    suspend fun initSubscription(wsRequest: WebSocketRequest, contextResolver: ContextResolver): Flow<String>
 
     suspend fun startSubscription(wsRequest: WebSocketRequest, wsPayload: WebSocketPayload, ): Flow<String>
 
diff --git a/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandlerImpl.kt b/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandlerImpl.kt
index c39ecdd..795af4a 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandlerImpl.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/async/SubscriptionHandlerImpl.kt
@@ -25,7 +25,10 @@ class SubscriptionHandlerImpl(
     private val operationStore: OperationStore = OperationStoreImpl()
 ) : SubscriptionHandler, JsonSerializer by jsonSerializer, RequestPerformer by requestPerformer {
 
-    override suspend fun initSubscription(wsRequest: WebSocketRequest, contextResolver: ContextResolver<*>): Flow<String> {
+    override suspend fun initSubscription(
+        wsRequest: WebSocketRequest,
+        contextResolver: ContextResolver
+    ): Flow<String> {
         subscriptionListener?.onNewConnection(wsRequest.sessionId)
         val context = contextResolver.resolveContext(wsRequest)
         sessionStore.saveContext(wsRequest.sessionId, context)
@@ -41,7 +44,11 @@ class SubscriptionHandlerImpl(
 
         return flow {
             operationStore.startOperation(wsRequest.sessionId, operationId) {
-                val context = sessionStore.getContext(wsRequest.sessionId)
+                val context = sessionStore.getContext(wsRequest.sessionId).getOrElse {
+                    it.printStackTrace()
+                    return@startOperation
+                }
+
                 subscriptionListener?.onStartSubscription(wsRequest.sessionId, context, operationId, graphQLRequest)
 
                 performRequest(graphQLRequest, context, requestListener)
@@ -56,15 +63,21 @@ class SubscriptionHandlerImpl(
         val operationId = wsPayload.id ?: return flowOf(serializeWebSocketPayload(connectionError))
 
         operationStore.stopOperation(wsRequest.sessionId, operationId)
-        val context = sessionStore.getContext(wsRequest.sessionId)
-        subscriptionListener?.onStopSubscription(wsRequest.sessionId, context, operationId)
+        sessionStore.getContext(wsRequest.sessionId).fold(onSuccess = { context ->
+            subscriptionListener?.onStopSubscription(wsRequest.sessionId, context, operationId)
+        }, onFailure = {
+            it.printStackTrace()
+        })
 
         return flowOf(serializeWebSocketPayload(connectionComplete(operationId)))
     }
 
     override suspend fun endSubscription(sessionId: String) {
         if (operationStore.hasOperationForSessionId(sessionId)) {
-            val context = sessionStore.getContext(sessionId)
+            val context = sessionStore.getContext(sessionId).getOrElse {
+                it.printStackTrace()
+                return
+            }
             subscriptionListener?.onCloseConnection(sessionId, context)
 
             sessionStore.clearContext(sessionId)
diff --git a/server/src/main/kotlin/com/arianegraphql/server/config/ArianeServerConfiguration.kt b/server/src/main/kotlin/com/arianegraphql/server/config/ArianeServerConfiguration.kt
index 210fd65..38a07a3 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/config/ArianeServerConfiguration.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/config/ArianeServerConfiguration.kt
@@ -15,7 +15,7 @@ open class ArianeServerConfiguration(
     val path: String,
     val isPlaygroundEnabled: Boolean,
     val enableCORS: Boolean,
-    val contextResolver: ContextResolver<*>,
+    val contextResolver: ContextResolver,
     val serverListener: ServerListener?,
     val requestListener: RequestListener?,
     val subscriptionListener: SubscriptionListener?
diff --git a/server/src/main/kotlin/com/arianegraphql/server/context/ContextResolver.kt b/server/src/main/kotlin/com/arianegraphql/server/context/ContextResolver.kt
index 292ca32..363b0be 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/context/ContextResolver.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/context/ContextResolver.kt
@@ -1,14 +1,15 @@
 package com.arianegraphql.server.context
 
 import com.arianegraphql.server.request.IncomingRequest
+import graphql.GraphQLContext
 
-interface ContextResolver<R: Any> {
-    suspend fun resolveContext(request: IncomingRequest): R?
+interface ContextResolver {
+    suspend fun resolveContext(request: IncomingRequest): GraphQLContext
 }
 
-@JvmInline value class FunctionalContextResolver<R: Any>(
-    private val lambda: suspend (request: IncomingRequest) -> R?
-) : ContextResolver<R> {
+@JvmInline value class FunctionalContextResolver(
+    private val lambda: suspend (request: IncomingRequest) -> GraphQLContext
+) : ContextResolver {
 
-    override suspend fun resolveContext(request: IncomingRequest): R? = lambda(request)
+    override suspend fun resolveContext(request: IncomingRequest): GraphQLContext = lambda(request)
 }
\ No newline at end of file
diff --git a/server/src/main/kotlin/com/arianegraphql/server/dsl/ArianeServerBuilder.kt b/server/src/main/kotlin/com/arianegraphql/server/dsl/ArianeServerBuilder.kt
index 7cc0706..a7a801a 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/dsl/ArianeServerBuilder.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/dsl/ArianeServerBuilder.kt
@@ -8,6 +8,7 @@ import com.arianegraphql.server.listener.RequestListener
 import com.arianegraphql.server.listener.ServerListener
 import com.arianegraphql.server.listener.SubscriptionListener
 import com.arianegraphql.server.request.IncomingRequest
+import graphql.GraphQLContext
 
 @GraphQLSchemaDslMarker
 open class ArianeServerBuilder : RuntimeWiringBuilder() {
@@ -24,15 +25,15 @@ open class ArianeServerBuilder : RuntimeWiringBuilder() {
     var requestListener: RequestListener? = null
     var subscriptionListener: SubscriptionListener? = null
 
-    var contextResolver: ContextResolver<*> = object : ContextResolver<Any> {
-        override suspend fun resolveContext(request: IncomingRequest): Any? = null
+    var contextResolver: ContextResolver = object : ContextResolver {
+        override suspend fun resolveContext(request: IncomingRequest): GraphQLContext = GraphQLContext.of(emptyMap<Any, Any>())
     }
 
-    fun <R : Any> context(contextResolver: ContextResolver<R>) {
+    fun <R : Any> context(contextResolver: ContextResolver) {
         this.contextResolver = contextResolver
     }
 
-    fun <R : Any> context(contextResolver: suspend (request: IncomingRequest) -> R?) {
+    fun <R : Any> context(contextResolver: suspend (request: IncomingRequest) -> GraphQLContext) {
         this.contextResolver = FunctionalContextResolver(contextResolver)
     }
 
diff --git a/server/src/main/kotlin/com/arianegraphql/server/listener/SubscriptionListener.kt b/server/src/main/kotlin/com/arianegraphql/server/listener/SubscriptionListener.kt
index fdd1e31..b7de361 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/listener/SubscriptionListener.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/listener/SubscriptionListener.kt
@@ -1,16 +1,17 @@
 package com.arianegraphql.server.listener
 
 import com.arianegraphql.server.graphql.GraphQLRequest
+import graphql.GraphQLContext
 
 interface SubscriptionListener {
 
     fun onNewConnection(sessionId: String) {}
 
-    fun onConnected(sessionId: String, context: Any?) {}
+    fun onConnected(sessionId: String, context: GraphQLContext) {}
 
-    fun onStartSubscription(sessionId: String, context: Any?, operationId: String, graphQLRequest: GraphQLRequest) {}
+    fun onStartSubscription(sessionId: String, context: GraphQLContext, operationId: String, graphQLRequest: GraphQLRequest) {}
 
-    fun onStopSubscription(sessionId: String, context: Any?, operationId: String) {} //TODO NOT CALLED
+    fun onStopSubscription(sessionId: String, context: GraphQLContext, operationId: String) {} //TODO NOT CALLED
 
-    fun onCloseConnection(sessionId: String, context: Any?) {} //TODO NOT CALLED
+    fun onCloseConnection(sessionId: String, context: GraphQLContext) {} //TODO NOT CALLED
 }
\ No newline at end of file
diff --git a/server/src/main/kotlin/com/arianegraphql/server/store/SessionStore.kt b/server/src/main/kotlin/com/arianegraphql/server/store/SessionStore.kt
index 6b86b51..a752064 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/store/SessionStore.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/store/SessionStore.kt
@@ -1,10 +1,12 @@
 package com.arianegraphql.server.store
 
+import graphql.GraphQLContext
+
 interface SessionStore {
 
-    suspend fun saveContext(sessionId: String, context: Any?)
+    suspend fun saveContext(sessionId: String, context: GraphQLContext)
 
-    suspend fun getContext(sessionId: String): Any?
+    suspend fun getContext(sessionId: String): Result<GraphQLContext>
 
     suspend fun clearContext(sessionId: String)
 }
\ No newline at end of file
diff --git a/server/src/main/kotlin/com/arianegraphql/server/store/SessionStoreImpl.kt b/server/src/main/kotlin/com/arianegraphql/server/store/SessionStoreImpl.kt
index f37c19e..1d55894 100644
--- a/server/src/main/kotlin/com/arianegraphql/server/store/SessionStoreImpl.kt
+++ b/server/src/main/kotlin/com/arianegraphql/server/store/SessionStoreImpl.kt
@@ -1,17 +1,19 @@
 package com.arianegraphql.server.store
 
+import graphql.GraphQLContext
 import java.util.concurrent.ConcurrentHashMap
 
 class SessionStoreImpl(
-    private val contextStore: MutableMap<String, Any> = ConcurrentHashMap<String, Any>()
-): SessionStore {
+    private val contextStore: MutableMap<String, GraphQLContext> = ConcurrentHashMap<String, GraphQLContext>()
+) : SessionStore {
 
-    override suspend fun saveContext(sessionId: String, context: Any?) {
-        context?.let { contextStore[sessionId] = context }
+    override suspend fun saveContext(sessionId: String, context: GraphQLContext) {
+        contextStore[sessionId] = context
     }
 
-    override suspend fun getContext(sessionId: String): Any? {
-        return contextStore[sessionId]
+    override suspend fun getContext(sessionId: String): Result<GraphQLContext> {
+        return contextStore[sessionId]?.let { Result.success(it) }
+            ?: Result.failure(IllegalStateException("Session with id '$sessionId' not found."))
     }
 
     override suspend fun clearContext(sessionId: String) {
diff --git a/server/src/test/kotlin/com/arianegraphql/server/store/SessionStoreImplTest.kt b/server/src/test/kotlin/com/arianegraphql/server/store/SessionStoreImplTest.kt
index fa6ce91..e9bde8b 100644
--- a/server/src/test/kotlin/com/arianegraphql/server/store/SessionStoreImplTest.kt
+++ b/server/src/test/kotlin/com/arianegraphql/server/store/SessionStoreImplTest.kt
@@ -1,5 +1,6 @@
 package com.arianegraphql.server.store
 
+import graphql.GraphQLContext
 import io.github.serpro69.kfaker.Faker
 import kotlinx.coroutines.runBlocking
 import org.junit.jupiter.api.BeforeEach
@@ -9,7 +10,7 @@ import org.junit.jupiter.api.Assertions.*
 
 internal class SessionStoreImplTest {
 
-    private val contextStore = mutableMapOf<String, Any>()
+    private val contextStore = mutableMapOf<String, GraphQLContext>()
     private lateinit var sessionStore: SessionStoreImpl
 
     @BeforeEach
@@ -21,32 +22,29 @@ internal class SessionStoreImplTest {
     fun `saveContext() should store context into hashmap`() = runBlocking {
         contextStore.clear()
         val sessionId = "foobar"
-        val context = FakeContext()
-        sessionStore.saveContext(sessionId, context)
+        val fakeContext = GraphQLContext.of(
+            mutableMapOf<Any, Any>(
+                "favoriteGalaxy" to Faker().space.galaxy()
+            )
+        )
 
-        assertEquals(context, contextStore[sessionId])
-    }
-
-    @Test
-    fun `saveContext() should not store null context`() = runBlocking {
-        contextStore.clear()
-        val sessionId = "barfoo"
+        sessionStore.saveContext(sessionId, fakeContext)
 
-        sessionStore.saveContext(sessionId, null)
-        assertEquals(0, contextStore.size)
+        assertEquals(fakeContext, contextStore[sessionId])
     }
 
     @Test
     fun `getContext() should return the context`() = runBlocking {
         val sessionId = "FOO_BAR"
+        val fakeContext = GraphQLContext.of(
+            mutableMapOf<Any, Any>(
+                "favoriteGalaxy" to Faker().space.galaxy()
+            )
+        )
 
-        val context = FakeContext()
-
-        contextStore[sessionId] = context
+        contextStore[sessionId] = fakeContext
 
         val actual = sessionStore.getContext(sessionId)
-        assertEquals(context, actual)
+        assertEquals(Result.success(fakeContext), actual)
     }
-}
-
-data class FakeContext(val favoriteGalaxy: String = Faker().space.galaxy())
\ No newline at end of file
+}
\ No newline at end of file