diff --git a/app/src/main/java/com/unibuy/smartdevice/external/mqtt/MqttManager.java b/app/src/main/java/com/unibuy/smartdevice/external/mqtt/MqttManager.java
index 5965b65..6d2bdc7 100644
--- a/app/src/main/java/com/unibuy/smartdevice/external/mqtt/MqttManager.java
+++ b/app/src/main/java/com/unibuy/smartdevice/external/mqtt/MqttManager.java
@@ -110,6 +110,13 @@ public class MqttManager {
                     } catch (Exception e) {
                         logs.info("OTA resume on connect failed: " + e.getMessage());
                     }
+                    // 連線就緒後補送未送出的交易結案（先清 in-flight，舊連線在途的送出已失效）。
+                    try {
+                        com.unibuy.smartdevice.tools.TransactionOutbox.onConnected(
+                                com.unibuy.smartdevice.MyApp.getInstance().getApplicationContext());
+                    } catch (Exception e) {
+                        logs.info("Transaction outbox resume on connect failed: " + e.getMessage());
+                    }
                 })
                 .buildAsync();
 
@@ -149,6 +156,10 @@ public class MqttManager {
                 }
                 int temperature = DevXinYuanController.getTemperature();
                 publishHeartbeat(ver, temperature);
+                // 心跳順帶 drain 發件箱：即使連線健康時單筆 publish 曾失敗，也能在此定時補送，
+                // 不必等到下次斷線重連（修正 outbox「只在重連才補送」的缺陷）。
+                com.unibuy.smartdevice.tools.TransactionOutbox.resumeIfPending(
+                        MyApp.getInstance().getApplicationContext());
             } catch (Exception e) {
                 logs.info("Error in heartbeat scheduler: " + e.getMessage());
             }
@@ -361,14 +372,26 @@ public class MqttManager {
      * @param payload 由 TransactionFinalizeBuilder.build() 產生的完整 payload
      */
     public void publishTransactionFinalize(TransactionFinalizePayload payload) {
+        // 改走本地發件箱（Outbox）：先持久化、再嘗試送出；斷線 / App 被殺不再直接遺失，
+        // 連線恢復時由 TransactionOutbox.resumeIfPending 補送。後台對同一 flow_id 完全冪等，重送安全。
+        com.unibuy.smartdevice.tools.TransactionOutbox.submit(
+                MyApp.getInstance().getApplicationContext(), payload);
+    }
+
+    /**
+     * 實際把交易結案 JSON 送到 MQTT（由 {@link com.unibuy.smartdevice.tools.TransactionOutbox} 呼叫）。
+     *
+     * @param payloadJson 已序列化的 payload
+     * @param onSuccess   送出成功（broker PUBACK）後的回呼，用來從發件箱移除該筆
+     * @param onFailure   送出失敗（throwable）後的回呼，用來清 in-flight / 累計失敗次數
+     * @return true=已交給 MQTT 送出（成敗待 callback）；false=未連線（保留於發件箱待下次補送）
+     */
+    public boolean rawPublishTransaction(String payloadJson, Runnable onSuccess, Runnable onFailure) {
         if (client == null || !client.getState().isConnected()) {
-            logs.info("Cannot publish finalize: MQTT not connected");
-            return;
+            logs.info("rawPublishTransaction: MQTT not connected, kept in outbox for resend");
+            return false;
         }
-
-        String payloadJson = gson.toJson(payload);
         String topic = "machine/" + serialNo + "/transaction";
-
         client.publishWith()
                 .topic(topic)
                 .payload(payloadJson.getBytes(StandardCharsets.UTF_8))
@@ -376,11 +399,18 @@ public class MqttManager {
                 .send()
                 .whenComplete((publishResult, throwable) -> {
                     if (throwable != null) {
-                        logs.info("Failed to publish transaction finalize: " + throwable.getMessage());
+                        logs.info("rawPublishTransaction failed (will retry): " + throwable.getMessage());
+                        if (onFailure != null) {
+                            onFailure.run();
+                        }
                     } else {
-                        logs.info("Transaction finalize published to " + topic + ": " + payloadJson);
+                        logs.info("Transaction published to " + topic);
+                        if (onSuccess != null) {
+                            onSuccess.run();
+                        }
                     }
                 });
+        return true;
     }
 
     public interface MqttCommandListener {
diff --git a/app/src/main/java/com/unibuy/smartdevice/structure/DevSetStructure.java b/app/src/main/java/com/unibuy/smartdevice/structure/DevSetStructure.java
index a9e9436..70151fa 100644
--- a/app/src/main/java/com/unibuy/smartdevice/structure/DevSetStructure.java
+++ b/app/src/main/java/com/unibuy/smartdevice/structure/DevSetStructure.java
@@ -194,7 +194,7 @@ public class DevSetStructure {
     /** flowType 2 電子票證(卡片支付)：刷卡機開啟且卡片支付子項開啟。 */
     public boolean canCardPay() { return isDevNFCPay && isDevCardPay; }
 
-    /** flowType 4 手機支付：刷卡機開啟且手機支付子項開啟。 */
+    /** flowType 10 手機支付：刷卡機開啟且手機支付子項開啟。 */
     public boolean canMobilePay() { return isDevNFCPay && isDevMobilePay; }
 
     /** flowType 3 玉山 EsunPay：掃碼開啟且玉山子項開啟。 */
diff --git a/app/src/main/java/com/unibuy/smartdevice/structure/mqtt/TransactionFinalizePayload.java b/app/src/main/java/com/unibuy/smartdevice/structure/mqtt/TransactionFinalizePayload.java
index 763ab4a..9ac991a 100644
--- a/app/src/main/java/com/unibuy/smartdevice/structure/mqtt/TransactionFinalizePayload.java
+++ b/app/src/main/java/com/unibuy/smartdevice/structure/mqtt/TransactionFinalizePayload.java
@@ -184,7 +184,7 @@ public class TransactionFinalizePayload {
 
         /**
          * 支付類型代碼：
-         * 1:信用卡, 2:悠遊卡/一卡通, 3:掃碼支付, 4:紙鈔機, 5:通行碼, 6:取貨碼,
+         * 1:信用卡, 2:悠遊卡/一卡通, 3:掃碼支付, 4:紙鈔機, 10:手機支付, 5:通行碼, 6:取貨碼,
          * 7:來店禮, 8:問卷, 9:零錢, 30:LINE Pay, 31:街口, 32:悠遊付, 33:Pi,
          * 34:全盈+, 40:會員驗證取貨, 41:員工卡, 60:點數全額折抵。
          */
diff --git a/app/src/main/java/com/unibuy/smartdevice/tools/TransactionOutbox.java b/app/src/main/java/com/unibuy/smartdevice/tools/TransactionOutbox.java
new file mode 100644
index 0000000..27cc08f
--- /dev/null
+++ b/app/src/main/java/com/unibuy/smartdevice/tools/TransactionOutbox.java
@@ -0,0 +1,217 @@
+package com.unibuy.smartdevice.tools;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+
+import com.google.gson.Gson;
+import com.unibuy.smartdevice.exception.Logs;
+import com.unibuy.smartdevice.external.mqtt.MqttManager;
+import com.unibuy.smartdevice.structure.mqtt.TransactionFinalizePayload;
+
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * 交易結案上報的本地發件箱（Outbox）。
+ *
+ * 目的：解決「出貨完成但 MQTT 斷線 / App 被殺 → finalize 直接遺失」的漏送。
+ *
+ * 設計重點：
+ *  - 單一背景執行緒（outboxExecutor）處理所有落地 / 送出 / 移除：不卡 UI 主執行緒、
+ *    天然序列化（不需 synchronized、無鎖競爭）。
+ *  - 每筆交易一個 SharedPreferences key（"tx:" + entryId）：O(1) 落地 / 移除，無整包重寫。
+ *  - 落地用 commit()（在背景緒，安全）→ 送出前確保已在磁碟，crash / 斷電不遺失。
+ *  - in-flight 防重送：正在送、等 PUBACK 的單會被標記，drain 不重複送同一筆（避免流量放大）。
+ *  - 送出成功（broker PUBACK）才移除；失敗則清 in-flight、累計失敗次數，留待下次 drain。
+ *  - 重試上限 / 死信：連續送出失敗達上限的「毒丸」單移入 dead: key（保留資料、不丟），
+ *    停止反覆重送並出聲，交維運處理。
+ *  - 補送觸發：連線恢復（onConnected，順帶清 in-flight 防殘留）＋ 心跳定時（每 60s）。
+ *
+ * 可靠性：QoS1 + broker PUBACK 後負責後續投遞；後台對同一 flow_id 完全冪等
+ * （serial 前綴防撞號 + 終態短路 + lockForUpdate），故重送 / 亂序皆安全、不會重複扣庫存。
+ *
+ * entryId = flow_id + ":" + status，讓 pending / failed / completed 各自獨立不互蓋。
+ */
+public class TransactionOutbox {
+
+    private static final String PREFS = "TransactionOutboxPrefs";
+    private static final String KEY_PREFIX = "tx:";     // 待送出
+    private static final String ATT_PREFIX = "att:";    // 累計送出失敗次數
+    private static final String DEAD_PREFIX = "dead:";  // 死信（達重試上限，保留待維運）
+    /** 連續送出失敗（broker 層）達此上限即移入死信，停止反覆重送。 */
+    private static final int MAX_ATTEMPTS = 100;
+    /** 堆積警戒線：超過即出聲警告（不丟資料），代表網路 / broker 長時間異常。 */
+    private static final int WARN_THRESHOLD = 200;
+
+    private static final Logs logs = new Logs(TransactionOutbox.class);
+    private static final Gson gson = new Gson();
+
+    /** 單一背景執行緒：序列化所有 outbox 操作，不卡 UI、不需鎖。 */
+    private static final ExecutorService outboxExecutor = Executors.newSingleThreadExecutor(r -> {
+        Thread t = new Thread(r, "tx-outbox");
+        t.setDaemon(true);
+        return t;
+    });
+
+    /** 正在送出、等待 PUBACK 的 entryId。只在 outboxExecutor 單一緒存取 → 免鎖。 */
+    private static final Set<String> inflight = new HashSet<>();
+
+    /**
+     * 結案上報：背景緒落地後嘗試送出（成功才移除）。
+     * 呼叫端（出貨 / 付款結案的 UI 主執行緒）只做一次輕量序列化後立即返回，不阻塞、不做磁碟 I/O。
+     */
+    public static void submit(Context context, TransactionFinalizePayload payload) {
+        if (context == null || payload == null) {
+            return;
+        }
+        final Context app = context.getApplicationContext();
+        final String json;
+        final String entryId;
+        try {
+            json = gson.toJson(payload);
+            String flowId = payload.getFlow_id();
+            String status = (payload.getOrder() != null && payload.getOrder().getStatus() != null)
+                    ? payload.getOrder().getStatus() : "completed";
+            entryId = (flowId != null ? flowId : "unknown") + ":" + status;
+        } catch (Exception e) {
+            logs.info("TransactionOutbox.submit serialize failed: " + e.getMessage());
+            return;
+        }
+        outboxExecutor.execute(() -> {
+            persist(app, entryId, json);
+            drain(app);
+        });
+    }
+
+    /** 心跳定時呼叫：背景緒補送所有未送出的交易（保留 in-flight 狀態）。 */
+    public static void resumeIfPending(Context context) {
+        if (context == null) {
+            return;
+        }
+        final Context app = context.getApplicationContext();
+        outboxExecutor.execute(() -> drain(app));
+    }
+
+    /** 連線恢復呼叫：先清 in-flight（舊連線在途的送出已失效，避免殘留卡住）再補送。 */
+    public static void onConnected(Context context) {
+        if (context == null) {
+            return;
+        }
+        final Context app = context.getApplicationContext();
+        outboxExecutor.execute(() -> {
+            inflight.clear();
+            drain(app);
+        });
+    }
+
+    // ==== 以下全部只在 outboxExecutor 單一背景緒執行，故無併發、不需鎖 ====
+
+    /** 落地單筆（commit 同步寫磁碟，確保 publish 前已在磁碟）。 */
+    private static void persist(Context app, String entryId, String json) {
+        try {
+            prefs(app).edit().putString(KEY_PREFIX + entryId, json).commit();
+            logs.info("TransactionOutbox persisted " + entryId);
+            int count = countPending(prefs(app).getAll());
+            if (count > WARN_THRESHOLD) {
+                logs.info("TransactionOutbox WARNING: " + count
+                        + " entries pending — MQTT/network likely down for a long time");
+            }
+        } catch (Exception e) {
+            logs.info("TransactionOutbox.persist failed: " + e.getMessage());
+        }
+    }
+
+    /** 嘗試送出所有未送出且未在途的交易；未連線即停，留待下次 drain。 */
+    private static void drain(Context app) {
+        try {
+            Map<String, ?> all = prefs(app).getAll();
+            int pending = countPending(all);
+            if (pending == 0) {
+                return;
+            }
+            logs.info("TransactionOutbox.drain: " + pending + " pending, " + inflight.size() + " in-flight");
+            for (Map.Entry<String, ?> e : all.entrySet()) {
+                String key = e.getKey();
+                if (key == null || !key.startsWith(KEY_PREFIX)) {
+                    continue;
+                }
+                final String entryId = key.substring(KEY_PREFIX.length());
+                if (inflight.contains(entryId)) {
+                    continue; // A：已在送、等 PUBACK，不重送
+                }
+                Object v = e.getValue();
+                if (!(v instanceof String)) {
+                    continue;
+                }
+                boolean sent = MqttManager.getInstance().rawPublishTransaction(
+                        (String) v,
+                        () -> outboxExecutor.execute(() -> onSendSuccess(app, entryId)),
+                        () -> outboxExecutor.execute(() -> onSendFailure(app, entryId)));
+                if (sent) {
+                    inflight.add(entryId);
+                } else {
+                    // 未連線：其餘也會失敗，留待下次 drain（連線恢復或下次心跳）。
+                    logs.info("TransactionOutbox.drain: not connected, keep pending for next drain");
+                    break;
+                }
+            }
+        } catch (Exception e) {
+            logs.info("TransactionOutbox.drain failed: " + e.getMessage());
+        }
+    }
+
+    /** 送出成功（PUBACK）：清 in-flight、移除該筆與其失敗計數。 */
+    private static void onSendSuccess(Context app, String entryId) {
+        try {
+            inflight.remove(entryId);
+            prefs(app).edit().remove(KEY_PREFIX + entryId).remove(ATT_PREFIX + entryId).apply();
+            logs.info("TransactionOutbox removed " + entryId + " (published)");
+        } catch (Exception e) {
+            logs.info("TransactionOutbox.onSendSuccess failed: " + e.getMessage());
+        }
+    }
+
+    /** 送出失敗：清 in-flight、累計失敗；達上限移入死信（保留資料、不丟、出聲）。 */
+    private static void onSendFailure(Context app, String entryId) {
+        try {
+            inflight.remove(entryId);
+            SharedPreferences p = prefs(app);
+            int att = p.getInt(ATT_PREFIX + entryId, 0) + 1;
+            if (att >= MAX_ATTEMPTS) {
+                String json = p.getString(KEY_PREFIX + entryId, null);
+                SharedPreferences.Editor ed = p.edit()
+                        .remove(KEY_PREFIX + entryId)
+                        .remove(ATT_PREFIX + entryId);
+                if (json != null) {
+                    ed.putString(DEAD_PREFIX + entryId, json); // 保留資料供維運處理，不丟棄
+                }
+                ed.apply();
+                logs.info("TransactionOutbox DEAD-LETTER " + entryId + " after " + att
+                        + " failed attempts — moved to dead:, NEEDS OPS ATTENTION");
+            } else {
+                p.edit().putInt(ATT_PREFIX + entryId, att).apply();
+                logs.info("TransactionOutbox send failed " + entryId + " attempt " + att + "/" + MAX_ATTEMPTS);
+            }
+        } catch (Exception e) {
+            logs.info("TransactionOutbox.onSendFailure failed: " + e.getMessage());
+        }
+    }
+
+    /** 計算待送出（tx:）筆數；傳入已取得的快照避免重複 getAll。 */
+    private static int countPending(Map<String, ?> all) {
+        int n = 0;
+        for (String key : all.keySet()) {
+            if (key != null && key.startsWith(KEY_PREFIX)) {
+                n++;
+            }
+        }
+        return n;
+    }
+
+    private static SharedPreferences prefs(Context app) {
+        return app.getSharedPreferences(PREFS, Context.MODE_PRIVATE);
+    }
+}
diff --git a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyDialog.java b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyDialog.java
index 7004621..ab19e3a 100644
--- a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyDialog.java
+++ b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyDialog.java
@@ -150,7 +150,7 @@ public class BuyDialog extends DialogAbstract {
         });
 
         this.binding.buttonNfcPhone.setOnClickListener(v -> {
-            MyApp.getInstance().getReportFlowInfoData().setFlowType(4);
+            MyApp.getInstance().getReportFlowInfoData().setFlowType(10); // 手機感應＝payment_type 10，全程一致（避免失敗上報撞後台 4=紙鈔機）
             gotoDialog();
         });
 
@@ -492,7 +492,7 @@ public class BuyDialog extends DialogAbstract {
         // basic 購物模式(本專案 general/demo) 且為實際付款方式(1/2/3/4/9/30/70) 時：
         // 為本筆生成新流水號，並上報 pending（「進付款一律留底」）。pending → completed/failed 全程共用此 flow_id。
         // 通行碼(5)/來店禮(7) 非付款，不在此處理；employee_card(晟崴)/pickup_sheet(中國醫) 無付款不送，後台資料不受影響。
-        boolean realPayment = (flowType == 1 || flowType == 2 || flowType == 3 || flowType == 4
+        boolean realPayment = (flowType == 1 || flowType == 2 || flowType == 3 || flowType == 10
                 || flowType == 9 || flowType == 30 || flowType == 70);
         if ("basic".equals(MyApp.getInstance().getShoppingMode()) && realPayment) {
             flowInfo.setMqttFlowId(com.unibuy.smartdevice.tools.FlowIdGenerator.next(MyApp.getInstance()));
@@ -509,7 +509,7 @@ public class BuyDialog extends DialogAbstract {
             case 3:
                 changeDialog(CheckoutEsunPayDialog.class);
                 break;
-            case 4:
+            case 10:
                 changeDialog(CheckoutNfcPhoneDialog.class);
                 break;
             case 5:
@@ -539,7 +539,7 @@ public class BuyDialog extends DialogAbstract {
         switch (flowType) {
             case 1:  return d.canCreditCard();   // 信用卡（刷卡機）
             case 2:  return d.canCardPay();      // 電子票證/卡片支付（刷卡機）
-            case 4:  return d.canMobilePay();    // 手機支付（刷卡機）
+            case 10: return d.canMobilePay();    // 手機支付（刷卡機）
             case 3:  return d.canEsunPay();      // 玉山（掃碼）
             case 30: return d.canTapPay();       // TapPay（掃碼）
             case 70: return d.canLinePay();      // Line 官方支付（獨立）
diff --git a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyPickupCodeDialog.java b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyPickupCodeDialog.java
index ad3024d..c7992a8 100644
--- a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyPickupCodeDialog.java
+++ b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/BuyPickupCodeDialog.java
@@ -218,7 +218,7 @@ public class BuyPickupCodeDialog extends DialogAbstract {
             case 3:
                 changeDialog(CheckoutEsunPayDialog.class);
                 break;
-            case 4:
+            case 10:
                 changeDialog(CheckoutNfcPhoneDialog.class);
                 break;
             case 5:
diff --git a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/CheckoutNfcPhoneDialog.java b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/CheckoutNfcPhoneDialog.java
index 2be368f..2e160ba 100644
--- a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/CheckoutNfcPhoneDialog.java
+++ b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/CheckoutNfcPhoneDialog.java
@@ -108,10 +108,8 @@ public class CheckoutNfcPhoneDialog extends DialogAbstract {
                                     if (message.equals("0000")) {
                                         MyApp.getInstance().getReportFlowInfoData().setFlowStatusType(1);
                                         binding.textStatus.setText(DevNFCPay.recordMessage(message));
-                                        // NfcPhone(手機支付)：刷卡機 NCCC 電文無法區分手機錢包/實體卡，
-                                        // 依使用者所選付款鈕歸類為 payment_type=10（手機支付）。
-                                        // 路由鍵 flowType=4 僅用於 BuyDialog 開啟本 Dialog，這裡覆寫為實際上報值。
-                                        MyApp.getInstance().getReportFlowInfoData().setFlowType(10);
+                                        // NfcPhone(手機支付)：flowType 自 BuyDialog 按鈕起即為 10（手機支付），
+                                        // 成功/失敗/取消各出口全程一致上報，不再於此覆寫（4 已不再代表手機感應）。
                                         // [MQTT Finalize 重構] 支付成功不再呼叫舊 B600(reportFlowInfo)；
                                         // 直接進出貨流程，由 DispatchDialog 以 MQTT Finalize 統一上報結案（含發票/扣庫存）。
                                         changeDispatch();
diff --git a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceBarcodeDialog.java b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceBarcodeDialog.java
index ecfbc19..98d8c7e 100644
--- a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceBarcodeDialog.java
+++ b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceBarcodeDialog.java
@@ -375,7 +375,7 @@ public class InvoiceBarcodeDialog extends DialogAbstract {
             case 3:
                 changeDialog(CheckoutEsunPayDialog.class);
                 break;
-            case 4:
+            case 10:
                 changeDialog(CheckoutNfcPhoneDialog.class);
                 break;
             case 9:
diff --git a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceCustomerIdentifierDialog.java b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceCustomerIdentifierDialog.java
index e713aea..b67f1d0 100644
--- a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceCustomerIdentifierDialog.java
+++ b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceCustomerIdentifierDialog.java
@@ -401,7 +401,7 @@ public class InvoiceCustomerIdentifierDialog extends DialogAbstract {
             case 3:
                 changeDialog(CheckoutEsunPayDialog.class);
                 break;
-            case 4:
+            case 10:
                 changeDialog(CheckoutNfcPhoneDialog.class);
                 break;
             case 9:
diff --git a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceDonationDialog.java b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceDonationDialog.java
index 938a702..bc23f96 100644
--- a/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceDonationDialog.java
+++ b/app/src/main/java/com/unibuy/smartdevice/ui/dialog/InvoiceDonationDialog.java
@@ -274,7 +274,7 @@ public class InvoiceDonationDialog extends DialogAbstract {
             case 3:
                 changeDialog(CheckoutEsunPayDialog.class);
                 break;
-            case 4:
+            case 10:
                 changeDialog(CheckoutNfcPhoneDialog.class);
                 break;
             case 9: