diff --git a/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapReceivingBenchmark.kt b/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapReceivingBenchmark.kt
index 9f364ba56..62c3e676a 100644
--- a/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapReceivingBenchmark.kt
+++ b/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapReceivingBenchmark.kt
@@ -170,7 +170,7 @@ class GiftWrapReceivingBenchmark {
                 wrap.pubKey.hexToByteArray(),
             )
 
-        benchmarkRule.measureRepeated { assertNotNull(innerJson?.let { Event.fromJson(it) }) }
+        benchmarkRule.measureRepeated { assertNotNull(innerJson.let { Event.fromJson(it) }) }
     }
 
     @Test
@@ -205,6 +205,6 @@ class GiftWrapReceivingBenchmark {
                 seal.pubKey.hexToByteArray(),
             )
 
-        benchmarkRule.measureRepeated { assertNotNull(innerJson?.let { Rumor.fromJson(it) }) }
+        benchmarkRule.measureRepeated { assertNotNull(innerJson.let { Rumor.fromJson(it) }) }
     }
 }
diff --git a/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapSigningBenchmark.kt b/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapSigningBenchmark.kt
index ce0ffccaf..1395ab720 100644
--- a/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapSigningBenchmark.kt
+++ b/benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/GiftWrapSigningBenchmark.kt
@@ -138,7 +138,7 @@ class GiftWrapSigningBenchmark {
         benchmarkRule.measureRepeated {
             runBlocking {
                 GiftWrapEvent.create(
-                    event = seal!!,
+                    event = seal,
                     recipientPubKey = receiver.pubKey,
                 )
             }
diff --git a/quartz/src/androidHostTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.android.kt b/quartz/src/androidHostTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.android.kt
new file mode 100644
index 000000000..34edaf77c
--- /dev/null
+++ b/quartz/src/androidHostTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.android.kt
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz
+
+actual class TestResourceLoader actual constructor() {
+    actual fun loadString(file: String): String {
+        TODO("Not yet implemented")
+    }
+}
diff --git a/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.kt b/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.kt
index 81c31d65b..633888a45 100644
--- a/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.kt
+++ b/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/TestResourceLoader.kt
@@ -20,26 +20,6 @@
  */
 package com.vitorpamplona.quartz
 
-/**
- * Copyright (c) 2025 Vitor Pamplona
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
- * Software, and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
 expect class TestResourceLoader() {
     fun loadString(file: String): String
 }
diff --git a/quartz/src/iosMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessEngine.ios.kt b/quartz/src/iosMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessEngine.ios.kt
new file mode 100644
index 000000000..a87275781
--- /dev/null
+++ b/quartz/src/iosMain/kotlin/com/vitorpamplona/quartz/nip64Chess/ChessEngine.ios.kt
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip64Chess
+
+actual class ChessEngine actual constructor() {
+    actual fun getFen(): String {
+        TODO("Not yet implemented")
+    }
+
+    actual fun loadFen(fen: String) {
+    }
+
+    actual fun reset() {
+    }
+
+    actual fun makeMove(san: String): MoveResult {
+        TODO("Not yet implemented")
+    }
+
+    actual fun makeMove(
+        from: String,
+        to: String,
+        promotion: PieceType?,
+    ): MoveResult {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getLegalMoves(): List<String> {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getLegalMovesFrom(square: String): List<String> {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isLegalMove(san: String): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isLegalMove(
+        from: String,
+        to: String,
+        promotion: PieceType?,
+    ): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isCheckmate(): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isStalemate(): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun isInCheck(): Boolean {
+        TODO("Not yet implemented")
+    }
+
+    actual fun undoMove() {
+    }
+
+    actual fun getPosition(): ChessPosition {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getSideToMove(): Color {
+        TODO("Not yet implemented")
+    }
+
+    actual fun getMoveHistory(): List<String> {
+        TODO("Not yet implemented")
+    }
+}