diff --git a/example/build.gradle b/example/build.gradle
index 8d53208..3c67ea2 100644
--- a/example/build.gradle
+++ b/example/build.gradle
@@ -32,8 +32,7 @@ android {
 }
 
 dependencies {
-    implementation project(path: ':fcl-android')
-
+    implementation project(path: ':fcl')
     implementation 'androidx.core:core-ktx:1.6.0'
     implementation 'androidx.appcompat:appcompat:1.3.1'
     implementation 'com.google.android.material:material:1.3.0'
diff --git a/fcl-android/.gitignore b/fcl/.gitignore
similarity index 100%
rename from fcl-android/.gitignore
rename to fcl/.gitignore
diff --git a/fcl-android/build.gradle b/fcl/build.gradle
similarity index 100%
rename from fcl-android/build.gradle
rename to fcl/build.gradle
diff --git a/fcl-android/consumer-rules.pro b/fcl/consumer-rules.pro
similarity index 100%
rename from fcl-android/consumer-rules.pro
rename to fcl/consumer-rules.pro
diff --git a/fcl-android/proguard-rules.pro b/fcl/proguard-rules.pro
similarity index 100%
rename from fcl-android/proguard-rules.pro
rename to fcl/proguard-rules.pro
diff --git a/fcl-android/src/androidTest/java/io/outblock/fcl/ExampleInstrumentedTest.kt b/fcl/src/androidTest/java/io/outblock/fcl/ExampleInstrumentedTest.kt
similarity index 94%
rename from fcl-android/src/androidTest/java/io/outblock/fcl/ExampleInstrumentedTest.kt
rename to fcl/src/androidTest/java/io/outblock/fcl/ExampleInstrumentedTest.kt
index b7ac60b..da83fc8 100644
--- a/fcl-android/src/androidTest/java/io/outblock/fcl/ExampleInstrumentedTest.kt
+++ b/fcl/src/androidTest/java/io/outblock/fcl/ExampleInstrumentedTest.kt
@@ -1,13 +1,11 @@
 package io.outblock.fcl
 
-import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.ext.junit.runners.AndroidJUnit4
-
+import androidx.test.platform.app.InstrumentationRegistry
+import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
 
-import org.junit.Assert.*
-
 /**
  * Instrumented test, which will execute on an Android device.
  *
diff --git a/fcl-android/src/main/AndroidManifest.xml b/fcl/src/main/AndroidManifest.xml
similarity index 100%
rename from fcl-android/src/main/AndroidManifest.xml
rename to fcl/src/main/AndroidManifest.xml
diff --git a/fcl-android/src/main/java/io/outblock/fcl/Fcl.kt b/fcl/src/main/java/io/outblock/fcl/Fcl.kt
similarity index 99%
rename from fcl-android/src/main/java/io/outblock/fcl/Fcl.kt
rename to fcl/src/main/java/io/outblock/fcl/Fcl.kt
index 311e54a..2a5110d 100644
--- a/fcl-android/src/main/java/io/outblock/fcl/Fcl.kt
+++ b/fcl/src/main/java/io/outblock/fcl/Fcl.kt
@@ -161,7 +161,6 @@ object Fcl {
 
     fun verifyAccountProof(includeDomainTag: Boolean = false): FclResult<Boolean> {
         assert(Thread.currentThread() != Looper.getMainLooper().thread) { "can't call this method in main thread." }
-
         return processResult {
             runBlocking { AccountProofRequest().request(includeDomainTag) }
         }
diff --git a/fcl-android/src/main/java/io/outblock/fcl/FlowApi.kt b/fcl/src/main/java/io/outblock/fcl/FlowApi.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/FlowApi.kt
rename to fcl/src/main/java/io/outblock/fcl/FlowApi.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/cadence/Cadences.kt b/fcl/src/main/java/io/outblock/fcl/cadence/Cadences.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/cadence/Cadences.kt
rename to fcl/src/main/java/io/outblock/fcl/cadence/Cadences.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/config/Config.kt b/fcl/src/main/java/io/outblock/fcl/config/Config.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/config/Config.kt
rename to fcl/src/main/java/io/outblock/fcl/config/Config.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/lifecycle/FCLContentProvider.kt b/fcl/src/main/java/io/outblock/fcl/lifecycle/FCLContentProvider.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/lifecycle/FCLContentProvider.kt
rename to fcl/src/main/java/io/outblock/fcl/lifecycle/FCLContentProvider.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/lifecycle/LifecycleObserver.kt b/fcl/src/main/java/io/outblock/fcl/lifecycle/LifecycleObserver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/lifecycle/LifecycleObserver.kt
rename to fcl/src/main/java/io/outblock/fcl/lifecycle/LifecycleObserver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/models/FclResult.kt b/fcl/src/main/java/io/outblock/fcl/models/FclResult.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/models/FclResult.kt
rename to fcl/src/main/java/io/outblock/fcl/models/FclResult.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/models/Signable.kt b/fcl/src/main/java/io/outblock/fcl/models/Signable.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/models/Signable.kt
rename to fcl/src/main/java/io/outblock/fcl/models/Signable.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/models/response/PollingResponse.kt b/fcl/src/main/java/io/outblock/fcl/models/response/PollingResponse.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/models/response/PollingResponse.kt
rename to fcl/src/main/java/io/outblock/fcl/models/response/PollingResponse.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/models/response/ResponseStatus.kt b/fcl/src/main/java/io/outblock/fcl/models/response/ResponseStatus.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/models/response/ResponseStatus.kt
rename to fcl/src/main/java/io/outblock/fcl/models/response/ResponseStatus.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/provider/Provider.kt b/fcl/src/main/java/io/outblock/fcl/provider/Provider.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/provider/Provider.kt
rename to fcl/src/main/java/io/outblock/fcl/provider/Provider.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/AccountProofRequest.kt b/fcl/src/main/java/io/outblock/fcl/request/AccountProofRequest.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/AccountProofRequest.kt
rename to fcl/src/main/java/io/outblock/fcl/request/AccountProofRequest.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/AuthnRequest.kt b/fcl/src/main/java/io/outblock/fcl/request/AuthnRequest.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/AuthnRequest.kt
rename to fcl/src/main/java/io/outblock/fcl/request/AuthnRequest.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/AuthzRequest.kt b/fcl/src/main/java/io/outblock/fcl/request/AuthzRequest.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/AuthzRequest.kt
rename to fcl/src/main/java/io/outblock/fcl/request/AuthzRequest.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/SignMessageRequest.kt b/fcl/src/main/java/io/outblock/fcl/request/SignMessageRequest.kt
similarity index 94%
rename from fcl-android/src/main/java/io/outblock/fcl/request/SignMessageRequest.kt
rename to fcl/src/main/java/io/outblock/fcl/request/SignMessageRequest.kt
index 8a3163e..e537eff 100644
--- a/fcl-android/src/main/java/io/outblock/fcl/request/SignMessageRequest.kt
+++ b/fcl/src/main/java/io/outblock/fcl/request/SignMessageRequest.kt
@@ -11,6 +11,7 @@ import io.outblock.fcl.utils.FclException
 internal class SignMessageRequest {
 
     suspend fun request(message: String): SignMessageResponse {
+        Fcl.currentUser ?: throw FclException(FclError.unauthenticated)
         val service = Fcl.currentUser?.services?.first { it.type == FCLServiceType.userSignature.value }
             ?: throw FclException(FclError.invaildService)
 
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/builder/FclBuilder.kt b/fcl/src/main/java/io/outblock/fcl/request/builder/FclBuilder.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/builder/FclBuilder.kt
rename to fcl/src/main/java/io/outblock/fcl/request/builder/FclBuilder.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/resolver/AccountsResolver.kt b/fcl/src/main/java/io/outblock/fcl/request/resolver/AccountsResolver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/resolver/AccountsResolver.kt
rename to fcl/src/main/java/io/outblock/fcl/request/resolver/AccountsResolver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/resolver/CadenceResolver.kt b/fcl/src/main/java/io/outblock/fcl/request/resolver/CadenceResolver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/resolver/CadenceResolver.kt
rename to fcl/src/main/java/io/outblock/fcl/request/resolver/CadenceResolver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/resolver/RefBlockResolver.kt b/fcl/src/main/java/io/outblock/fcl/request/resolver/RefBlockResolver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/resolver/RefBlockResolver.kt
rename to fcl/src/main/java/io/outblock/fcl/request/resolver/RefBlockResolver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/resolver/Resolver.kt b/fcl/src/main/java/io/outblock/fcl/request/resolver/Resolver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/resolver/Resolver.kt
rename to fcl/src/main/java/io/outblock/fcl/request/resolver/Resolver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/resolver/SequenceNumberResolver.kt b/fcl/src/main/java/io/outblock/fcl/request/resolver/SequenceNumberResolver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/resolver/SequenceNumberResolver.kt
rename to fcl/src/main/java/io/outblock/fcl/request/resolver/SequenceNumberResolver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/request/resolver/SignatureResolver.kt b/fcl/src/main/java/io/outblock/fcl/request/resolver/SignatureResolver.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/request/resolver/SignatureResolver.kt
rename to fcl/src/main/java/io/outblock/fcl/request/resolver/SignatureResolver.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/HttpPostRpc.kt b/fcl/src/main/java/io/outblock/fcl/strategies/HttpPostRpc.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/HttpPostRpc.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/HttpPostRpc.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/Strategies.kt b/fcl/src/main/java/io/outblock/fcl/strategies/Strategies.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/Strategies.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/Strategies.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/Utils.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/Utils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/Utils.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/Utils.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnect.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnect.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnect.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnect.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectDappDelegate.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectDappDelegate.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectDappDelegate.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectDappDelegate.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectHook.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectHook.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectHook.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectHook.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectMethod.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectMethod.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectMethod.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectMethod.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectSession.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectSession.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectSession.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WalletConnectSession.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WcRpc.kt b/fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WcRpc.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/strategies/walletconnect/WcRpc.kt
rename to fcl/src/main/java/io/outblock/fcl/strategies/walletconnect/WcRpc.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/ContextUtils.kt b/fcl/src/main/java/io/outblock/fcl/utils/ContextUtils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/ContextUtils.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/ContextUtils.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt b/fcl/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/FclError.kt b/fcl/src/main/java/io/outblock/fcl/utils/FclError.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/FclError.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/FclError.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/FclExtensions.kt b/fcl/src/main/java/io/outblock/fcl/utils/FclExtensions.kt
similarity index 84%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/FclExtensions.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/FclExtensions.kt
index e2e82c0..2ca42a0 100644
--- a/fcl-android/src/main/java/io/outblock/fcl/utils/FclExtensions.kt
+++ b/fcl/src/main/java/io/outblock/fcl/utils/FclExtensions.kt
@@ -1,5 +1,6 @@
 package io.outblock.fcl.utils
 
+import android.os.Looper
 import androidx.annotation.WorkerThread
 import com.nftco.flow.sdk.FlowBlock
 import com.nftco.flow.sdk.bytesToHex
@@ -18,6 +19,9 @@ fun Fcl.getLatestBlock(sealed: Boolean = true): FlowBlock {
 
 @WorkerThread
 fun Fcl.verifyUserSignature(message: String, signatures: List<SignMessageResponse>): Boolean {
+    assert(Thread.currentThread() != Looper.getMainLooper().thread) { "can't call this method in main thread." }
+    currentUser ?: throw FclException(FclError.unauthenticated)
+
     val result = query {
         cadence(CADENCE_VERIFY_USER_SIGNATURE)
         arg { address(signatures.firstOrNull()?.address.orEmpty()) }
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/FlowFieldUtils.kt b/fcl/src/main/java/io/outblock/fcl/utils/FlowFieldUtils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/FlowFieldUtils.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/FlowFieldUtils.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/JsonUtils.kt b/fcl/src/main/java/io/outblock/fcl/utils/JsonUtils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/JsonUtils.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/JsonUtils.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/Log.kt b/fcl/src/main/java/io/outblock/fcl/utils/Log.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/Log.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/Log.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/SignableUtils.kt b/fcl/src/main/java/io/outblock/fcl/utils/SignableUtils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/SignableUtils.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/SignableUtils.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/StringExtensions.kt b/fcl/src/main/java/io/outblock/fcl/utils/StringExtensions.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/StringExtensions.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/StringExtensions.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/parse/FclResultParse.kt b/fcl/src/main/java/io/outblock/fcl/utils/parse/FclResultParse.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/utils/parse/FclResultParse.kt
rename to fcl/src/main/java/io/outblock/fcl/utils/parse/FclResultParse.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/webview/FCLWebView.kt b/fcl/src/main/java/io/outblock/fcl/webview/FCLWebView.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/webview/FCLWebView.kt
rename to fcl/src/main/java/io/outblock/fcl/webview/FCLWebView.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/webview/WebViewActivity.kt b/fcl/src/main/java/io/outblock/fcl/webview/WebViewActivity.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/webview/WebViewActivity.kt
rename to fcl/src/main/java/io/outblock/fcl/webview/WebViewActivity.kt
diff --git a/fcl-android/src/main/java/io/outblock/fcl/webview/WebViewUtils.kt b/fcl/src/main/java/io/outblock/fcl/webview/WebViewUtils.kt
similarity index 100%
rename from fcl-android/src/main/java/io/outblock/fcl/webview/WebViewUtils.kt
rename to fcl/src/main/java/io/outblock/fcl/webview/WebViewUtils.kt
diff --git a/fcl-android/src/main/res/values/themes.xml b/fcl/src/main/res/values/themes.xml
similarity index 94%
rename from fcl-android/src/main/res/values/themes.xml
rename to fcl/src/main/res/values/themes.xml
index 4470ba3..e9c1ae4 100644
--- a/fcl-android/src/main/res/values/themes.xml
+++ b/fcl/src/main/res/values/themes.xml
@@ -1,6 +1,6 @@
-<resources xmlns:tools="http://schemas.android.com/tools">
-    <style name="AppTheme">
-    </style>
+<resources>
+
+    <style name="AppTheme"></style>
 
     <style name="AppTheme.Transparent">
         <item name="android:windowIsTranslucent">true</item>
diff --git a/fcl-android/src/test/java/io/outblock/fcl/ExampleUnitTest.kt b/fcl/src/test/java/io/outblock/fcl/ExampleUnitTest.kt
similarity index 100%
rename from fcl-android/src/test/java/io/outblock/fcl/ExampleUnitTest.kt
rename to fcl/src/test/java/io/outblock/fcl/ExampleUnitTest.kt
diff --git a/settings.gradle b/settings.gradle
index 5891c7c..c00bf82 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -1,3 +1,3 @@
 rootProject.name = "fcl-android"
 include ':example'
-include ':fcl-android'
+include ':fcl'