diff --git a/.gitignore b/.gitignore
index 5058fb6..e264418 100644
--- a/.gitignore
+++ b/.gitignore
@@ -40,3 +40,4 @@ DerivedData/
 !*.xcodeproj/xcshareddata/
 !*.xcworkspace/contents.xcworkspacedata
 **/xcshareddata/WorkspaceSettings.xcsettings
+kotlin-js-store/
\ No newline at end of file
diff --git a/settings.gradle.kts b/settings.gradle.kts
index a297655..ede34db 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -18,12 +18,12 @@ dependencyResolutionManagement {
         create("libs") {
             version("android-tools-gradle", "7.2.0")
             version("kotlin", "1.7.10")
-            version("ktor", "2.0.3")
+            version("ktor", "2.1.1")
 
             library("ktor-client-core", "io.ktor", "ktor-client-core").versionRef("ktor")
             library("ktor-client-android", "io.ktor", "ktor-client-android").versionRef("ktor")
             library("ktor-client-darwin", "io.ktor", "ktor-client-darwin").versionRef("ktor")
-            library("ktor-client-jvm", "io.ktor", "ktor-client-cio").versionRef("ktor")
+            library("ktor-client-jvm", "io.ktor", "ktor-client-java").versionRef("ktor")
             library("ktor-client-js", "io.ktor", "ktor-client-js").versionRef("ktor")
             library("kotlinx-coroutines", "org.jetbrains.kotlinx", "kotlinx-coroutines-core").version("1.6.1")
             library("kotlinx-serialization", "org.jetbrains.kotlinx", "kotlinx-serialization-json").version("1.3.3")
@@ -38,4 +38,4 @@ dependencyResolutionManagement {
             plugin("kotlin.serialization", "org.jetbrains.kotlin.plugin.serialization").versionRef("kotlin")
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/androidMain/kotlin/com/liftric/cognito/idp/core/Engine.kt b/src/androidMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
new file mode 100644
index 0000000..416677c
--- /dev/null
+++ b/src/androidMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
@@ -0,0 +1,6 @@
+package com.liftric.cognito.idp.core
+
+import io.ktor.client.engine.HttpClientEngine
+import io.ktor.client.engine.android.Android
+
+internal actual val Engine: HttpClientEngine = Android.create()
diff --git a/src/commonMain/kotlin/com/liftric/cognito/idp/IdentityProviderClient.kt b/src/commonMain/kotlin/com/liftric/cognito/idp/IdentityProviderClient.kt
index 6f8ecf7..a24b549 100644
--- a/src/commonMain/kotlin/com/liftric/cognito/idp/IdentityProviderClient.kt
+++ b/src/commonMain/kotlin/com/liftric/cognito/idp/IdentityProviderClient.kt
@@ -3,6 +3,7 @@ package com.liftric.cognito.idp
 import com.liftric.cognito.idp.core.*
 import io.ktor.client.*
 import io.ktor.client.call.*
+import io.ktor.client.engine.*
 import io.ktor.client.plugins.*
 import io.ktor.client.request.*
 import io.ktor.client.statement.*
@@ -18,14 +19,14 @@ import kotlinx.serialization.json.Json
  * AWS Cognito Identity Provider client.
  * Provides common request methods.
  */
-open class IdentityProviderClient(region: String, clientId: String) : IdentityProvider {
+open class IdentityProviderClient(region: String, clientId: String, engine: HttpClientEngine? = null) : IdentityProvider {
     private val json = Json {
         allowStructuredMapKeys = true
         ignoreUnknownKeys = true
         explicitNulls = false
     }
     private val configuration = Configuration(region, clientId)
-    private val client = HttpClient {
+    private val client = HttpClient(engine ?: Engine) {
         expectSuccess = true
         /**
          * When referencing members that are in the
@@ -41,6 +42,8 @@ open class IdentityProviderClient(region: String, clientId: String) : IdentityPr
         }
     }
 
+    constructor(region: String, clientId: String) : this(region, clientId, null)
+
     override suspend fun signUp(
         username: String,
         password: String,
diff --git a/src/commonMain/kotlin/com/liftric/cognito/idp/core/Engine.kt b/src/commonMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
new file mode 100644
index 0000000..d697189
--- /dev/null
+++ b/src/commonMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
@@ -0,0 +1,5 @@
+package com.liftric.cognito.idp.core
+
+import io.ktor.client.engine.HttpClientEngine
+
+internal expect val Engine: HttpClientEngine
diff --git a/src/iosMain/kotlin/com/liftric/cognito/idp/core/Engine.kt b/src/iosMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
new file mode 100644
index 0000000..732576a
--- /dev/null
+++ b/src/iosMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
@@ -0,0 +1,7 @@
+package com.liftric.cognito.idp.core
+
+import io.ktor.client.engine.HttpClientEngine
+import io.ktor.client.engine.darwin.Darwin
+
+internal actual val Engine: HttpClientEngine = Darwin.create()
+
diff --git a/src/jsMain/kotlin/IdentityProviderJS.kt b/src/jsMain/kotlin/IdentityProviderJS.kt
index 7fc2018..a6faf13 100644
--- a/src/jsMain/kotlin/IdentityProviderJS.kt
+++ b/src/jsMain/kotlin/IdentityProviderJS.kt
@@ -2,6 +2,7 @@
 
 import com.liftric.cognito.idp.IdentityProviderClient
 import com.liftric.cognito.idp.core.*
+import io.ktor.client.engine.js.*
 import kotlinx.coroutines.MainScope
 import kotlinx.coroutines.promise
 import kotlin.js.Promise
diff --git a/src/jsMain/kotlin/com/liftric/cognito/idp/core/Engine.kt b/src/jsMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
new file mode 100644
index 0000000..6f70a30
--- /dev/null
+++ b/src/jsMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
@@ -0,0 +1,7 @@
+package com.liftric.cognito.idp.core
+
+import io.ktor.client.engine.HttpClientEngine
+import io.ktor.client.engine.js.Js
+
+internal actual val Engine: HttpClientEngine = Js.create()
+
diff --git a/src/jvmMain/kotlin/com/liftric/cognito/idp/core/Engine.kt b/src/jvmMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
new file mode 100644
index 0000000..77288f3
--- /dev/null
+++ b/src/jvmMain/kotlin/com/liftric/cognito/idp/core/Engine.kt
@@ -0,0 +1,6 @@
+package com.liftric.cognito.idp.core
+
+import io.ktor.client.engine.HttpClientEngine
+import io.ktor.client.engine.java.Java
+
+internal actual val Engine: HttpClientEngine = Java.create()