diff --git a/apps/extension/src/pages/wallet/smart-account/confirm/confirm.tsx b/apps/extension/src/pages/wallet/smart-account/confirm/confirm.tsx
index 3d406547c4..224c6aa18d 100644
--- a/apps/extension/src/pages/wallet/smart-account/confirm/confirm.tsx
+++ b/apps/extension/src/pages/wallet/smart-account/confirm/confirm.tsx
@@ -69,7 +69,7 @@ export const SmartAccountConfirmPage: FunctionComponent = observer(() => {
     insufficientBalance,
     balanceLoaded,
     retry,
-  } = useSmartAccountFee(chainId, vaultId, hexAddress, isValid);
+  } = useSmartAccountFee(chainId, hexAddress, isValid);
 
   const [isLoading, setIsLoading] = useState(false);
   const [error, setError] = useState<string | null>(null);
@@ -109,7 +109,8 @@ export const SmartAccountConfirmPage: FunctionComponent = observer(() => {
     insufficientBalance ||
     isFailed ||
     !balanceLoaded ||
-    isEstimating;
+    isEstimating ||
+    !feeDisplay;
 
   return (
     <HeaderLayout
diff --git a/apps/extension/src/pages/wallet/smart-account/confirm/hooks/use-smart-account-fee.ts b/apps/extension/src/pages/wallet/smart-account/confirm/hooks/use-smart-account-fee.ts
index 3ac955bd2e..470571fedf 100644
--- a/apps/extension/src/pages/wallet/smart-account/confirm/hooks/use-smart-account-fee.ts
+++ b/apps/extension/src/pages/wallet/smart-account/confirm/hooks/use-smart-account-fee.ts
@@ -1,23 +1,25 @@
 import { useCallback, useEffect, useMemo, useState } from "react";
-import { EstimateSmartAccountFeeMsg } from "@keplr-wallet/background";
-import { InExtensionMessageRequester } from "@keplr-wallet/router-extension";
-import { BACKGROUND_PORT } from "@keplr-wallet/router";
-import { CoinPretty, Int } from "@keplr-wallet/unit";
+import {
+  ALLOWED_DELEGATORS,
+  buildDummyAuthorizationList,
+} from "@keplr-wallet/background";
+import { computeEIP1559TxFees } from "@keplr-wallet/hooks-evm";
+import { CoinPretty, Dec, Int } from "@keplr-wallet/unit";
 import { useStore } from "../../../../../stores";
 import { formatFee } from "../../utils";
 
 type FeeState =
   | { status: "loading" }
-  | { status: "success"; estimatedFeeWei: string }
+  | { status: "success"; gasUsed: number; l1DataFee?: Dec }
   | { status: "error" };
 
 export function useSmartAccountFee(
   chainId: string,
-  vaultId: string,
   hexAddress: string,
   isValid: boolean
 ) {
-  const { chainStore, queriesStore, priceStore } = useStore();
+  const { chainStore, queriesStore, priceStore, ethereumAccountStore } =
+    useStore();
 
   const nativeCurrency = useMemo(() => {
     try {
@@ -30,46 +32,102 @@ export function useSmartAccountFee(
     }
   }, [chainStore, chainId]);
 
+  const evmChainId = useMemo(() => {
+    const unwrapped = chainStore.getModularChain(chainId).unwrapped;
+    if (unwrapped.type === "evm") return unwrapped.evm.chainId;
+    if (unwrapped.type === "ethermint") return unwrapped.evm.chainId;
+    return 0;
+  }, [chainStore, chainId]);
+
   const nativeSymbol = nativeCurrency?.coinDenom ?? "ETH";
 
   const [feeState, setFeeState] = useState<FeeState>({ status: "loading" });
   const [retryCount, setRetryCount] = useState(0);
 
   useEffect(() => {
-    if (!isValid) return;
+    if (!isValid || !hexAddress || !evmChainId) return;
     let cancelled = false;
     setFeeState({ status: "loading" });
-    new InExtensionMessageRequester()
-      .sendMessage(
-        BACKGROUND_PORT,
-        new EstimateSmartAccountFeeMsg(chainId, vaultId)
-      )
-      .then((result) => {
-        if (!cancelled)
+
+    const ethereumAccount = ethereumAccountStore.getAccount(chainId);
+
+    const modularChainInfo = chainStore.getModularChain(chainId);
+    const hasOpStackFee = modularChainInfo.hasFeature("op-stack-l1-data-fee");
+
+    ethereumAccount
+      .simulateGas(hexAddress, {
+        to: hexAddress,
+        value: "0x0",
+        data: "0x",
+        authorizationList: buildDummyAuthorizationList(
+          ALLOWED_DELEGATORS[0],
+          evmChainId
+        ),
+      })
+      .then(async (result) => {
+        if (cancelled) return;
+
+        let l1DataFee: Dec | undefined;
+        if (hasOpStackFee) {
+          const gasLimit = Math.ceil(result.gasUsed * 1.3);
+          const l1Fee = await ethereumAccount.simulateOpStackL1Fee({
+            to: hexAddress,
+            value: "0x0",
+            data: "0x",
+            gasLimit,
+          });
+          l1DataFee = new Dec(BigInt(l1Fee));
+        }
+
+        if (!cancelled) {
           setFeeState({
             status: "success",
-            estimatedFeeWei: result.estimatedFeeWei,
+            gasUsed: result.gasUsed,
+            l1DataFee,
           });
+        }
       })
       .catch(() => {
         if (!cancelled) setFeeState({ status: "error" });
       });
+
     return () => {
       cancelled = true;
     };
-  }, [chainId, vaultId, isValid, retryCount]);
+  }, [
+    chainId,
+    chainStore,
+    hexAddress,
+    evmChainId,
+    isValid,
+    retryCount,
+    ethereumAccountStore,
+  ]);
+
+  // Fee from reactive queries (feeHistory percentile + baseFee margin, fillUnsignedEVMTx와 동일 로직)
+  const ethereumQueries = queriesStore.get(chainId).ethereum;
+  const txFees = ethereumQueries
+    ? computeEIP1559TxFees(ethereumQueries, "average", chainId)
+    : undefined;
+
+  const estimatedFeeWei = useMemo(() => {
+    if (feeState.status !== "success") return null;
+    const feePerGas = txFees?.maxFeePerGas ?? txFees?.gasPrice;
+    if (!feePerGas || feePerGas.isZero()) return null;
+    const gasLimit = Math.ceil(feeState.gasUsed * 1.3);
+    let fee = feePerGas.mul(new Dec(gasLimit)).truncate();
+    if (feeState.l1DataFee) {
+      fee = fee.add(feeState.l1DataFee.truncate());
+    }
+    return "0x" + BigInt(fee.toString()).toString(16);
+  }, [feeState, txFees]);
 
-  const estimatedFeeWei =
-    feeState.status === "success" ? feeState.estimatedFeeWei : null;
   const isEstimating = feeState.status === "loading";
   const isFailed = feeState.status === "error";
 
   const feeDisplay = useMemo(
-    () =>
-      feeState.status === "success"
-        ? formatFee(feeState.estimatedFeeWei, nativeSymbol)
-        : null,
-    [feeState, nativeSymbol]
+    () => (estimatedFeeWei ? formatFee(estimatedFeeWei, nativeSymbol) : null),
+    [estimatedFeeWei, nativeSymbol]
   );
 
   const feeUsd = useMemo(() => {
diff --git a/packages/background/src/keyring-ethereum/handler.ts b/packages/background/src/keyring-ethereum/handler.ts
index e0dd0c791f..37e1fd80b8 100644
--- a/packages/background/src/keyring-ethereum/handler.ts
+++ b/packages/background/src/keyring-ethereum/handler.ts
@@ -12,7 +12,6 @@ import {
   CheckNeedEnableAccessForEVMMsg,
   UpgradeSmartAccountMsg,
   DowngradeSmartAccountMsg,
-  EstimateSmartAccountFeeMsg,
   GetEthereumAddressForVaultMsg,
 } from "./messages";
 import { KeyRingEthereumService } from "./service";
@@ -59,12 +58,6 @@ export const getHandler: (
           (msg as DowngradeSmartAccountMsg).chainId,
           (msg as DowngradeSmartAccountMsg).vaultId
         );
-      case EstimateSmartAccountFeeMsg:
-        return service.estimateSmartAccountFee(
-          env,
-          (msg as EstimateSmartAccountFeeMsg).chainId,
-          (msg as EstimateSmartAccountFeeMsg).vaultId
-        );
       case GetEthereumAddressForVaultMsg:
         return service.getEthAddressForVault(
           (msg as GetEthereumAddressForVaultMsg).chainId,
diff --git a/packages/background/src/keyring-ethereum/index.ts b/packages/background/src/keyring-ethereum/index.ts
index c0e3380a87..78d99aea49 100644
--- a/packages/background/src/keyring-ethereum/index.ts
+++ b/packages/background/src/keyring-ethereum/index.ts
@@ -1,3 +1,4 @@
 export * from "./messages";
 export * from "./service";
 export { ALLOWED_DELEGATORS } from "./constants";
+export { buildDummyAuthorizationList } from "./helper";
diff --git a/packages/background/src/keyring-ethereum/init.ts b/packages/background/src/keyring-ethereum/init.ts
index 927ee3b3ad..adbbd44ab0 100644
--- a/packages/background/src/keyring-ethereum/init.ts
+++ b/packages/background/src/keyring-ethereum/init.ts
@@ -7,7 +7,6 @@ import {
   CheckNeedEnableAccessForEVMMsg,
   UpgradeSmartAccountMsg,
   DowngradeSmartAccountMsg,
-  EstimateSmartAccountFeeMsg,
   GetEthereumAddressForVaultMsg,
 } from "./messages";
 import { ROUTE } from "./constants";
@@ -25,7 +24,6 @@ export function init(
   router.registerMessage(CheckNeedEnableAccessForEVMMsg);
   router.registerMessage(UpgradeSmartAccountMsg);
   router.registerMessage(DowngradeSmartAccountMsg);
-  router.registerMessage(EstimateSmartAccountFeeMsg);
   router.registerMessage(GetEthereumAddressForVaultMsg);
 
   router.addHandler(ROUTE, getHandler(service, permissionInteractionService));
diff --git a/packages/background/src/keyring-ethereum/messages.ts b/packages/background/src/keyring-ethereum/messages.ts
index 92d73b3ac8..f1b0d73d3a 100644
--- a/packages/background/src/keyring-ethereum/messages.ts
+++ b/packages/background/src/keyring-ethereum/messages.ts
@@ -179,45 +179,6 @@ export class DowngradeSmartAccountMsg extends Message<string> {
   }
 }
 
-export class EstimateSmartAccountFeeMsg extends Message<{
-  gasLimit: string;
-  maxFeePerGas: string;
-  maxPriorityFeePerGas: string;
-  estimatedFeeWei: string;
-}> {
-  public static type() {
-    return "estimate-smart-account-fee";
-  }
-
-  constructor(
-    public readonly chainId: string,
-    public readonly vaultId: string
-  ) {
-    super();
-  }
-
-  validateBasic(): void {
-    if (!this.chainId) {
-      throw new Error("chain id not set");
-    }
-    if (!this.vaultId) {
-      throw new Error("vault id not set");
-    }
-  }
-
-  override approveExternal(): boolean {
-    return false;
-  }
-
-  route(): string {
-    return ROUTE;
-  }
-
-  type(): string {
-    return EstimateSmartAccountFeeMsg.type();
-  }
-}
-
 export class GetEthereumAddressForVaultMsg extends Message<string> {
   public static type() {
     return "get-ethereum-address-for-vault";
diff --git a/packages/background/src/keyring-ethereum/service.ts b/packages/background/src/keyring-ethereum/service.ts
index 42a9548e99..29e4396c4a 100644
--- a/packages/background/src/keyring-ethereum/service.ts
+++ b/packages/background/src/keyring-ethereum/service.ts
@@ -5,6 +5,7 @@ import { AnalyticsService } from "../analytics";
 import { Env, EthereumProviderRpcError } from "@keplr-wallet/router";
 import {
   BatchSigningData,
+  BatchStrategy,
   DelegationStatus,
   EthereumBatchSignResponse,
   EthereumSignResponse,
@@ -48,8 +49,8 @@ import {
 } from "./helper";
 import { PermissionInteractiveService } from "../permission-interactive";
 import {
-  DEFAULT_EVM_CHAIN_ID,
   ALLOWED_DELEGATORS,
+  DEFAULT_EVM_CHAIN_ID,
   EIP5792_ERROR_ATOMICITY_NOT_SUPPORTED,
   EIP5792_ERROR_UNKNOWN_BUNDLE,
   ERC20_TRANSFER_SELECTOR,
@@ -66,10 +67,16 @@ export class KeyRingEthereumService {
   private readonly wsManager: EvmWebSocketManager;
   private readonly chainHandler: EvmChainHandler;
 
-  // EIP-5792: batchId → txHash mapping (in-memory, no persistence needed)
+  // EIP-5792: batchId → tx metadata mapping (in-memory, no persistence needed)
   private readonly batchCallsMap = new Map<
     string,
-    { txHash: string; chainId: string }
+    {
+      txHash: string;
+      chainId: string;
+      origin: string;
+      strategy: BatchStrategy;
+      apiVersion: string;
+    }
   >();
 
   constructor(
@@ -208,41 +215,6 @@ export class KeyRingEthereumService {
     );
   }
 
-  async estimateSmartAccountFee(
-    _env: Env,
-    chainId: string,
-    vaultId: string
-  ): Promise<{
-    gasLimit: string;
-    maxFeePerGas: string;
-    maxPriorityFeePerGas: string;
-    estimatedFeeWei: string;
-  }> {
-    const evmInfo = this.chainsService.getEVMInfoOrThrow(chainId);
-    const address = await this.getEthAddressForVault(chainId, vaultId);
-
-    const filled = await fillUnsignedEVMTx("", evmInfo, address, {
-      to: address,
-      value: "0x0",
-      data: "0x",
-      authorizationList: buildDummyAuthorizationList(
-        ALLOWED_DELEGATORS[0],
-        evmInfo.chainId
-      ),
-    });
-
-    const gasLimit = `0x${BigInt(filled.gasLimit ?? 0).toString(16)}`;
-    const maxFeePerGas = `0x${BigInt(filled.maxFeePerGas ?? 0).toString(16)}`;
-    const maxPriorityFeePerGas = `0x${BigInt(
-      filled.maxPriorityFeePerGas ?? 0
-    ).toString(16)}`;
-
-    const estimatedFeeWei =
-      "0x" + (BigInt(gasLimit) * BigInt(maxFeePerGas)).toString(16);
-
-    return { gasLimit, maxFeePerGas, maxPriorityFeePerGas, estimatedFeeWei };
-  }
-
   private async sendEip7702Tx(
     env: Env,
     chainId: string,
@@ -1464,7 +1436,13 @@ export class KeyRingEthereumService {
         {}
       );
 
-      this.batchCallsMap.set(batchId, { txHash, chainId: currentChainId });
+      this.batchCallsMap.set(batchId, {
+        txHash,
+        chainId: currentChainId,
+        origin,
+        strategy: batchResponse.strategy,
+        apiVersion: request.version || "1.0",
+      });
     } catch (error) {
       console.error(`Batch broadcast failed for ${batchId}:`, error);
       rethrowAsProviderError(error);
@@ -1491,7 +1469,7 @@ export class KeyRingEthereumService {
     }
 
     const entry = this.batchCallsMap.get(batchId);
-    if (!entry) {
+    if (!entry || entry.origin !== origin) {
       throw new EthereumProviderRpcError(
         EIP5792_ERROR_UNKNOWN_BUNDLE,
         "Unknown bundle ID"
@@ -1523,11 +1501,11 @@ export class KeyRingEthereumService {
     }
 
     return {
-      version: "1.0",
+      version: entry.apiVersion,
       chainId: `0x${evmInfo.chainId.toString(16)}`,
       id: batchId,
       status,
-      atomic: true,
+      atomic: entry.strategy === "atomic",
       receipts,
     };
   }
diff --git a/packages/stores-eth/src/account/base.ts b/packages/stores-eth/src/account/base.ts
index 93ba571a66..127696194d 100644
--- a/packages/stores-eth/src/account/base.ts
+++ b/packages/stores-eth/src/account/base.ts
@@ -140,7 +140,7 @@ export class EthereumAccountBase {
       throw new Error("No EVM chain info provided");
     }
 
-    const { to, value, data } = unsignedTx;
+    const { to, value, data, authorizationList } = unsignedTx;
 
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const keplr = (await this.getKeplr())!;
@@ -151,6 +151,7 @@ export class EthereumAccountBase {
         to,
         value,
         data,
+        ...(authorizationList ? { authorizationList } : {}),
       },
     ];
 
diff --git a/packages/stores-eth/src/batch.ts b/packages/stores-eth/src/batch.ts
new file mode 100644
index 0000000000..55bcf5f835
--- /dev/null
+++ b/packages/stores-eth/src/batch.ts
@@ -0,0 +1,51 @@
+import { Execute } from "ox/erc7821";
+import type { UnsignedEVMTransaction } from "./types";
+
+const EIP7702_DELEGATION_PREFIX = "0xef0100";
+
+/**
+ * EIP-5792 calls 배열을 StatelessDeleGator의 execute(bytes32,bytes) calldata로 변환.
+ * ox/erc7821 Execute.encodeData를 사용하여 ERC-7579 표준 준수를 보장.
+ */
+export function createAtomicBatchTransaction(
+  calls: { to?: string; data?: string; value?: string }[],
+  selectedAddress: string,
+  authorizationList?: UnsignedEVMTransaction["authorizationList"]
+): UnsignedEVMTransaction {
+  const data = Execute.encodeData(
+    calls.map((call, i) => {
+      if (!call.to) {
+        throw new Error(
+          `Call at index ${i}: contract deployment is not supported in batch execution`
+        );
+      }
+      return {
+        to: call.to as `0x${string}`,
+        value: BigInt(call.value ?? "0x0"),
+        data: (call.data ?? "0x") as `0x${string}`,
+      };
+    })
+  );
+
+  return {
+    to: selectedAddress,
+    data,
+    value: "0x0",
+    ...(authorizationList ? { authorizationList } : {}),
+  };
+}
+
+/**
+ * 미업그레이드 계정의 가스 추정을 위한 stateOverride 생성.
+ * eth_estimateGas 3번째 파라미터로 전달하여 delegation 코드를 주입.
+ */
+export function buildDelegationStateOverride(
+  address: string,
+  delegatorAddress: string
+): Record<string, { code: string }> {
+  return {
+    [address]: {
+      code: EIP7702_DELEGATION_PREFIX + delegatorAddress.toLowerCase().slice(2),
+    },
+  };
+}
diff --git a/packages/stores-eth/src/index.ts b/packages/stores-eth/src/index.ts
index 9f41b56298..553512ecb0 100644
--- a/packages/stores-eth/src/index.ts
+++ b/packages/stores-eth/src/index.ts
@@ -4,3 +4,4 @@ export * from "./constants";
 export * from "./currency-registrar";
 export * from "./types";
 export * from "./serialize";
+export * from "./batch";