diff --git a/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt
index c807deb..e84c396 100644
--- a/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt
+++ b/lib/src/main/java/com/circle/modularwallets/core/apis/bundler/BundlerApiImpl.kt
@@ -284,8 +284,10 @@ internal object BundlerApiImpl : BundlerApi {
             tmpUserOp.callGasLimit = BigInteger.ZERO
             tmpUserOp.preVerificationGas = BigInteger.ZERO
             if(paymaster != null){
-                tmpUserOp.paymasterVerificationGasLimit = BigInteger.ZERO
-                tmpUserOp.paymasterPostOpGasLimit = BigInteger.ZERO
+                // Preserve stub data values if available, only use ZERO as fallback
+                // This aligns with Viem's behavior: prioritize paymaster-provided gas limits
+                tmpUserOp.paymasterVerificationGasLimit = tmpUserOp.paymasterVerificationGasLimit ?: BigInteger.ZERO
+                tmpUserOp.paymasterPostOpGasLimit = tmpUserOp.paymasterPostOpGasLimit ?: BigInteger.ZERO
             } else{
                 tmpUserOp.paymasterVerificationGasLimit = null
                 tmpUserOp.paymasterPostOpGasLimit = null
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/Monad.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/Monad.kt
new file mode 100644
index 0000000..a68d3b9
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/Monad.kt
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object Monad : Chain() {
+    override val chainId: Long
+        get() = 143L
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/chains/MonadTestnet.kt b/lib/src/main/java/com/circle/modularwallets/core/chains/MonadTestnet.kt
new file mode 100644
index 0000000..7c91442
--- /dev/null
+++ b/lib/src/main/java/com/circle/modularwallets/core/chains/MonadTestnet.kt
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2025 Circle Internet Group, Inc. All rights reserved.
+ *  
+ * SPDX-License-Identifier: Apache-2.0.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at.
+ *
+ * Http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.circle.modularwallets.core.chains
+
+object MonadTestnet : Chain() {
+    override val chainId: Long
+        get() = 10143L
+}
+
diff --git a/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt b/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt
index 720abb1..e048147 100644
--- a/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt
+++ b/lib/src/main/java/com/circle/modularwallets/core/constants/AbiConstants.kt
@@ -39,6 +39,8 @@ internal val CONTRACT_ADDRESS: Map<String, String> = mapOf(
     Token.PolygonAmoy_USDC.name to "0x41e94eb019c0762f9bfcf9fb1e58725bfb0e7582",
     Token.Unichain_USDC.name to "0x078D782b760474a361dDA0AF3839290b0EF57AD6",
     Token.UnichainSepolia_USDC.name to "0x31d0220469e10c4E71834a79b1f276d740d3768F",
+    Token.Monad_USDC.name to "0x754704bc059f8c67012fed69bc8a327a5aafb603", // Note: MONAD mainnet USDC contract address
+    Token.MonadTestnet_USDC.name to "0x534b2f3A21130d7a60830c2Df862319e593943A3",
 )
 val CIRCLE_PLUGIN_ADD_OWNERS_ABI = """
 [
diff --git a/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt b/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt
index ba94306..61c5d63 100644
--- a/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt
+++ b/lib/src/main/java/com/circle/modularwallets/core/models/Token.kt
@@ -38,5 +38,7 @@ enum class Token {
     Polygon_USDC,
     PolygonAmoy_USDC,
     Unichain_USDC,
-    UnichainSepolia_USDC;
+    UnichainSepolia_USDC,
+    Monad_USDC,
+    MonadTestnet_USDC;
 }