diff --git a/amnet-native/app/card/ManualCardEntry.tsx b/amnet-native/app/card/ManualCardEntry.tsx
index 92ad58d..ed8b34c 100644
--- a/amnet-native/app/card/ManualCardEntry.tsx
+++ b/amnet-native/app/card/ManualCardEntry.tsx
@@ -1,6 +1,6 @@
-import {generateCardNumber} from "amnet-shared";
+import {generateCardNumber, DecodeAMAccessCode} from "amnet-shared";
 import {useCallback, useEffect, useLayoutEffect, useState} from "react";
-import {Platform, TextInput, TouchableOpacity, View} from "react-native";
+import {Alert, Platform, TextInput, TouchableOpacity, View} from "react-native";
 import {Button, Card, Divider, Paragraph, useTheme} from "react-native-paper";
 
 import {AMCard} from "../../models/AMCard";
@@ -18,7 +18,37 @@ export default function CardAddModal({navigation, route}) {
     const [cardName, setCardName] = useState('');
     const [cardNumber, setCardNumber] = useState('');
 
-    const cardAddCallback = useCallback((cardId: string, cardName: string) => {
+    const cardAddCallback = useCallback(async (cardId: string, cardName: string) => {
+        try {
+            // validate AM card numbers
+            cardId.startsWith('5') && DecodeAMAccessCode(cardId);
+        } catch {
+            const shouldContinue = await new Promise<boolean>(done => {
+                Alert.alert(
+                    "Invalid Access Code",
+                    "It looks like the access code isn't from an Amusement IC card. Please double-check the code, and if it's correct, note that some networks might still reject it.",
+                    [
+                        {
+                            style: "destructive",
+                            text: "Continue Anyway",
+                            onPress: () => done(true)
+                        },
+                        {
+                            style: "cancel",
+                            text: "Cancel",
+                            onPress: () => done(false)
+                        }
+                    ], {
+                        cancelable: true,
+                        onDismiss: () => done(false)
+                    });
+            })
+
+            if (!shouldContinue) {
+                return;
+            }
+        }
+
         const duplicateCard = realm.objects<AMCard>(AMCard.schema.name).find(x => x.code === cardId);
 
         if (duplicateCard) {
@@ -43,7 +73,8 @@ export default function CardAddModal({navigation, route}) {
         const themeOptions = canSave ? modalStyles.headerText : {color: theme.colors.outline};
 
         navigation.setOptions({
-            headerRight: () => <TouchableOpacity disabled={!canSave} onPress={() => cardAddCallback(cardNumber, cardName)}>
+            headerRight: () => <TouchableOpacity disabled={!canSave}
+                                                 onPress={() => cardAddCallback(cardNumber, cardName)}>
                 <Paragraph style={{...themeOptions, fontWeight: "600"}}>Save</Paragraph>
             </TouchableOpacity>
         })
@@ -90,7 +121,6 @@ export default function CardAddModal({navigation, route}) {
                 </Card.Content>
             </Card>
 
-            {/* only show card entry info when in create mode */}
             <Button mode="text" onPress={() => setCardNumber(generateCardNumber())}>Generate Access Code</Button>
         </View>
     )
diff --git a/amnet-native/metro.config.js b/amnet-native/metro.config.js
index 492244c..06fa400 100644
--- a/amnet-native/metro.config.js
+++ b/amnet-native/metro.config.js
@@ -6,7 +6,8 @@ module.exports = (async () => {
     const config = await getDefaultConfig(__dirname);
 
     config.resolver.extraNodeModules = {
-        'amnet-shared': resolve(__dirname, '../amnet-shared')
+        'amnet-shared': resolve(__dirname, '../amnet-shared'),
+        '@babel/runtime': resolve(__dirname, 'node_modules/@babel/runtime')
     };
 
     config.watchFolders = [
diff --git a/amnet-native/package-lock.json b/amnet-native/package-lock.json
index 7fba1f4..df113e0 100644
--- a/amnet-native/package-lock.json
+++ b/amnet-native/package-lock.json
@@ -9,6 +9,7 @@
       "version": "1.1.0",
       "hasInstallScript": true,
       "dependencies": {
+        "@babel/runtime": "^7.26.0",
         "@expo-google-fonts/jetbrains-mono": "^0.2.3",
         "@react-navigation/bottom-tabs": "^6.6.1",
         "@react-navigation/native": "^6.1.18",
@@ -47,7 +48,12 @@
     },
     "../amnet-shared": {
       "version": "1.0.0",
+      "dependencies": {
+        "big-integer": "^1.6.52",
+        "lodash": "^4.17.21"
+      },
       "devDependencies": {
+        "@types/lodash": "^4.17.14",
         "tsup": "^8.2.4",
         "typescript": "^5.5.4"
       }
diff --git a/amnet-native/package.json b/amnet-native/package.json
index 481af55..3ea5570 100644
--- a/amnet-native/package.json
+++ b/amnet-native/package.json
@@ -9,6 +9,7 @@
     "postinstall": "patch-package"
   },
   "dependencies": {
+    "@babel/runtime": "^7.26.0",
     "@expo-google-fonts/jetbrains-mono": "^0.2.3",
     "@react-navigation/bottom-tabs": "^6.6.1",
     "@react-navigation/native": "^6.1.18",