diff --git a/flutter/lib/features/pet_card/data/api_pet_card_repository.dart b/flutter/lib/features/pet_card/data/api_pet_card_repository.dart
new file mode 100644
index 0000000..e24c24f
--- /dev/null
+++ b/flutter/lib/features/pet_card/data/api_pet_card_repository.dart
@@ -0,0 +1,106 @@
+import 'package:dio/dio.dart';
+import 'package:tma_app/core/api/api_paging.dart';
+import 'package:tma_app/core/api/file_uploader.dart';
+import 'package:tma_app/core/api/server_file.dart';
+import 'package:tma_app/core/api/session_store.dart';
+import 'package:tma_app/core/utils/color_utils.dart';
+import 'package:tma_app/features/pet_card/data/pet_card_repository.dart';
+import 'package:tma_app/features/pet_card/domain/card_style.dart';
+import 'package:tma_app/features/pet_card/domain/pet_card.dart';
+
+/// 펫 명함 경로 (backend PetCardsController · RepresentativeCardController)
+const String _kCardsPath = '/pet-cards';
+String _representativePath(String petId) => '/pets/$petId/representative-card';
+
+/// 서버의 꾸미기 값 → 앱의 CardStyle (배경 그림은 앱 그림 경로 또는 서버 파일)
+CardStyle cardStyleFromApi(Map<String, Object?> json) {
+  final fallback = CardStyle.initial();
+  return CardStyle(
+    tint: colorFromHex(json['tint'] as String?) ?? fallback.tint,
+    tint2: colorFromHex(json['tint2'] as String?) ?? fallback.tint2,
+    nameBg: colorFromHex(json['nameBg'] as String?),
+    nameBgImage: (json['nameBgAsset'] as String?) ?? serverFileRefOrNull(json['nameBgFileId'] as String?),
+    textLight: json['textLight'] as bool? ?? false,
+    scrim: json['scrim'] as bool? ?? false,
+    scrimTone: ScrimTone.values.asNameMap()[json['scrimTone']] ?? ScrimTone.light,
+  );
+}
+
+PetCard petCardFromApi(Map<String, Object?> json) => PetCard(
+      id: json['id']! as String,
+      petId: json['petId']! as String,
+      code: json['code'] as String?,
+      style: cardStyleFromApi(json['style']! as Map<String, Object?>),
+    );
+
+/// 서버 저장소 — 배경 사진(기기 사진)은 저장할 때 올리고, 앱 그림은 경로만 보낸다
+class ApiPetCardRepository implements PetCardRepository {
+  ApiPetCardRepository({required Dio dio, required SessionStore session, required FileUploader uploader})
+      : _dio = dio,
+        _session = session,
+        _uploader = uploader;
+
+  final Dio _dio;
+  final SessionStore _session;
+  final FileUploader _uploader;
+
+  Future<Map<String, Object?>> _styleToApi(CardStyle style) async {
+    final image = style.nameBgImage;
+    final asset = image != null && isBundledAsset(image) ? image : null;
+    return {
+      'tint': hexOf(style.tint),
+      'tint2': hexOf(style.tint2),
+      'nameBg': style.nameBg == null ? null : hexOf(style.nameBg!),
+      'nameBgAsset': asset,
+      'nameBgFileId': asset == null ? await _uploader.ensureUploaded(image) : null,
+      'textLight': style.textLight,
+      'scrim': style.scrim,
+      'scrimTone': style.scrimTone.name,
+    };
+  }
+
+  @override
+  Future<PetCardBook> fetch() async {
+    if (!_session.hasSession) return (cards: const <PetCard>[], representatives: const <String, String>{});
+    final reps = <String, String>{};
+    final cards = await fetchAllPages(_dio, _kCardsPath, (json) {
+      final card = petCardFromApi(json);
+      if (json['isRepresentative'] == true) reps[card.petId] = card.id;
+      return card;
+    });
+    return (cards: cards, representatives: reps);
+  }
+
+  @override
+  Future<PetCard> create(String petId, CardStyle style) async {
+    final response = await _dio.post<Map<String, dynamic>>(
+      _kCardsPath,
+      data: {'petId': petId, 'style': await _styleToApi(style)},
+    );
+    return petCardFromApi(response.data!);
+  }
+
+  @override
+  Future<PetCard> update(String cardId, CardStyle style) async {
+    final response = await _dio.put<Map<String, dynamic>>(
+      '$_kCardsPath/$cardId',
+      data: {'style': await _styleToApi(style)},
+    );
+    return petCardFromApi(response.data!);
+  }
+
+  /// 대표 명함이었으면 서버가 대표 지정도 함께 지운다
+  @override
+  Future<void> delete(String cardId) => _dio.delete<void>('$_kCardsPath/$cardId');
+
+  @override
+  Future<void> setRepresentative(String petId, String cardId) =>
+      _dio.put<void>(_representativePath(petId), data: {'cardId': cardId});
+
+  @override
+  Future<void> clearRepresentative(String petId) => _dio.delete<void>(_representativePath(petId));
+
+  /// 서버가 아이를 지우면서 명함도 함께 지웠다
+  @override
+  Future<void> dropPet(String petId) async {}
+}
diff --git a/flutter/lib/features/pet_card/data/pet_card_repository.dart b/flutter/lib/features/pet_card/data/pet_card_repository.dart
index 1c93753..583271b 100644
--- a/flutter/lib/features/pet_card/data/pet_card_repository.dart
+++ b/flutter/lib/features/pet_card/data/pet_card_repository.dart
@@ -2,33 +2,43 @@ import 'dart:convert';
 
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import 'package:tma_app/core/api/dio_provider.dart';
+import 'package:tma_app/core/api/file_uploader.dart';
+import 'package:tma_app/core/api/session_store.dart';
+import 'package:tma_app/core/config/app_config.dart';
 import 'package:tma_app/core/storage/preferences_provider.dart';
+import 'package:tma_app/features/pet_card/data/api_pet_card_repository.dart';
 import 'package:tma_app/features/pet_card/domain/card_style.dart';
 import 'package:tma_app/features/pet_card/domain/pet_card.dart';
 
-/// 펫 명함 저장소 계약 — 백엔드 API 가 생기면 Dio 구현으로 바꾼다.
+/// 내 명함 + 아이별 대표 명함 (petId → cardId)
+typedef PetCardBook = ({List<PetCard> cards, Map<String, String> representatives});
+
+/// 펫 명함 저장소 계약 — 서버(ApiPetCardRepository) / 기기(LocalPetCardRepository)
 abstract interface class PetCardRepository {
-  Future<List<PetCard>> fetchCards();
+  Future<PetCardBook> fetch();
 
   Future<PetCard> create(String petId, CardStyle style);
 
   Future<PetCard> update(String cardId, CardStyle style);
 
+  /// 명함 삭제 — 대표 명함이었으면 대표 지정도 함께 사라진다
   Future<void> delete(String cardId);
 
-  /// 아이별 대표 명함 (petId → cardId)
-  Future<Map<String, String>> fetchRepresentatives();
-
   Future<void> setRepresentative(String petId, String cardId);
 
   Future<void> clearRepresentative(String petId);
+
+  /// 아이를 지웠을 때 그 아이의 명함을 지운다.
+  /// 서버 저장소는 할 일이 없다 — 서버가 아이를 지우면서 명함도 함께 지웠다.
+  Future<void> dropPet(String petId);
 }
 
 const String _kCardsKey = 'petCards.v1';
 const String _kRepKey = 'petCards.rep.v1';
 const String _kBgImagesKey = 'petCards.bgImages.v1';
 
-/// 임시 구현 — 기기(SharedPreferences)에 JSON 으로 저장한다.
+/// 기기 저장 모드 — SharedPreferences 에 JSON 으로 저장한다 (서버 없이 화면을 볼 때·테스트).
 class LocalPetCardRepository implements PetCardRepository {
   LocalPetCardRepository(this._prefs, {DateTime Function()? clock}) : _clock = clock ?? DateTime.now;
 
@@ -53,8 +63,10 @@ class LocalPetCardRepository implements PetCardRepository {
     return (jsonDecode(raw) as Map<String, Object?>).map((k, v) => MapEntry(k, v! as String));
   }
 
+  Future<void> _writeRep(Map<String, String> reps) => _prefs.setString(_kRepKey, jsonEncode(reps));
+
   @override
-  Future<List<PetCard>> fetchCards() async => _read();
+  Future<PetCardBook> fetch() async => (cards: _read(), representatives: _readRep());
 
   @override
   Future<PetCard> create(String petId, CardStyle style) async {
@@ -74,21 +86,24 @@ class LocalPetCardRepository implements PetCardRepository {
   @override
   Future<void> delete(String cardId) async {
     await _write(_read().where((c) => c.id != cardId).toList());
+    final reps = _readRep();
+    if (reps.containsValue(cardId)) await _writeRep(reps..removeWhere((_, id) => id == cardId));
   }
 
   @override
-  Future<Map<String, String>> fetchRepresentatives() async => _readRep();
+  Future<void> setRepresentative(String petId, String cardId) => _writeRep({..._readRep(), petId: cardId});
 
   @override
-  Future<void> setRepresentative(String petId, String cardId) =>
-      _prefs.setString(_kRepKey, jsonEncode({..._readRep(), petId: cardId}));
+  Future<void> clearRepresentative(String petId) => _writeRep(_readRep()..remove(petId));
 
   @override
-  Future<void> clearRepresentative(String petId) =>
-      _prefs.setString(_kRepKey, jsonEncode({..._readRep()}..remove(petId)));
+  Future<void> dropPet(String petId) async {
+    await _write(_read().where((c) => c.petId != petId).toList());
+    await clearRepresentative(petId);
+  }
 }
 
-/// 명함 배경으로 쓰려고 추가한 내 사진 (최대 [kMaxUserBackgrounds]장) — 다음에 명함을 꾸밀 때도 남는다
+/// 명함 배경으로 쓰려고 추가한 내 사진 (최대 [kMaxUserBackgrounds]장) — 다음에 명함을 꾸밀 때도 남는다 (기기에 둔다)
 const int kMaxUserBackgrounds = 5;
 
 class CardBackgroundRepository {
@@ -102,7 +117,14 @@ class CardBackgroundRepository {
 }
 
 final petCardRepositoryProvider = Provider<PetCardRepository>((ref) {
-  return LocalPetCardRepository(ref.watch(sharedPreferencesProvider));
+  return switch (ref.watch(dataModeProvider)) {
+    DataMode.local => LocalPetCardRepository(ref.watch(sharedPreferencesProvider)),
+    DataMode.api => ApiPetCardRepository(
+        dio: ref.watch(dioProvider),
+        session: ref.watch(sessionStoreProvider),
+        uploader: ref.watch(fileUploaderProvider),
+      ),
+  };
 });
 
 final cardBackgroundRepositoryProvider = Provider<CardBackgroundRepository>((ref) {
diff --git a/flutter/lib/features/pet_card/domain/pet_card.dart b/flutter/lib/features/pet_card/domain/pet_card.dart
index 67193e9..6106629 100644
--- a/flutter/lib/features/pet_card/domain/pet_card.dart
+++ b/flutter/lib/features/pet_card/domain/pet_card.dart
@@ -5,19 +5,23 @@ const int kMaxPetCards = 10;
 
 /// 펫 명함 — 어느 아이의 명함인지 + 꾸미기 값
 class PetCard {
-  const PetCard({required this.id, required this.petId, required this.style});
+  const PetCard({required this.id, required this.petId, required this.style, this.code});
 
   final String id;
   final String petId;
   final CardStyle style;
 
-  PetCard copyWith({CardStyle? style}) => PetCard(id: id, petId: petId, style: style ?? this.style);
+  /// 서버가 발급한 명함 코드 "0000-000" — 기기 저장 모드에는 없다 (화면은 displayCardCode 로 보여 준다)
+  final String? code;
 
-  Map<String, Object?> toJson() => {'id': id, 'petId': petId, 'style': style.toJson()};
+  PetCard copyWith({CardStyle? style}) => PetCard(id: id, petId: petId, style: style ?? this.style, code: code);
+
+  Map<String, Object?> toJson() => {'id': id, 'petId': petId, 'style': style.toJson(), 'code': ?code};
 
   factory PetCard.fromJson(Map<String, Object?> json) => PetCard(
         id: json['id']! as String,
         petId: json['petId']! as String,
         style: CardStyle.fromJson((json['style'] as Map<String, Object?>?) ?? const {}),
+        code: json['code'] as String?,
       );
 }
diff --git a/flutter/lib/features/pet_card/domain/pet_card_facts.dart b/flutter/lib/features/pet_card/domain/pet_card_facts.dart
index e6e8e5b..5306411 100644
--- a/flutter/lib/features/pet_card/domain/pet_card_facts.dart
+++ b/flutter/lib/features/pet_card/domain/pet_card_facts.dart
@@ -1,5 +1,7 @@
 // 명함에 적히는 값 계산 — 순수 함수
 
+import 'package:tma_app/features/pet_card/domain/pet_card.dart';
+
 /// 만 나이(년) — 이번 달 생일 날짜가 아직 안 왔으면 한 달을 덜 센다
 int petAgeYears(DateTime birth, DateTime today) {
   var months = (today.year - birth.year) * 12 + (today.month - birth.month);
@@ -21,7 +23,7 @@ String shortBirth(DateTime d) {
 }
 
 /// 명함 코드 "0000-000" — 같은 시드면 항상 같은 코드 (시안 petCardCode).
-/// 서버가 코드를 발급하게 되면 그 값으로 바꾼다.
+/// 서버가 발급한 코드가 없을 때(기기 저장 모드)만 쓴다 — [displayCardCode].
 String petCardCode(String seed) {
   var h = 0;
   for (final unit in seed.codeUnits) {
@@ -31,3 +33,6 @@ String petCardCode(String seed) {
   final b = ((h ~/ 10000) % 1000).toString().padLeft(3, '0');
   return '$a-$b';
 }
+
+/// 명함에 보여 줄 코드 — 서버가 발급한 코드, 없으면(기기 저장 모드) 명함 id 로 만든 코드
+String displayCardCode(PetCard card) => card.code ?? petCardCode(card.id);
diff --git a/flutter/lib/features/pet_card/presentation/pages/pet_card_detail_page.dart b/flutter/lib/features/pet_card/presentation/pages/pet_card_detail_page.dart
index 9780bc9..3c224ba 100644
--- a/flutter/lib/features/pet_card/presentation/pages/pet_card_detail_page.dart
+++ b/flutter/lib/features/pet_card/presentation/pages/pet_card_detail_page.dart
@@ -3,12 +3,14 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import 'package:tma_app/core/api/api_guard.dart';
 import 'package:tma_app/core/constants/app_colors.dart';
 import 'package:tma_app/core/constants/app_sizes.dart';
 import 'package:tma_app/core/router/app_routes.dart';
 import 'package:tma_app/core/theme/app_typography.dart';
 import 'package:tma_app/features/pet/presentation/providers/pet_providers.dart';
 import 'package:tma_app/features/pet_card/domain/pet_card.dart';
+import 'package:tma_app/features/pet_card/domain/pet_card_facts.dart';
 import 'package:tma_app/features/pet_card/presentation/providers/pet_card_providers.dart';
 import 'package:tma_app/features/pet_card/presentation/widgets/name_card.dart';
 import 'package:tma_app/features/pet_card/presentation/widgets/pet_id_card.dart';
@@ -46,10 +48,11 @@ class _PetCardDetailPageState extends ConsumerState<PetCardDetailPage> {
   final _capture = CaptureController();
 
   Future<void> _share(String petName) {
+    final card = ref.read(petCardsProvider).value?.cards.where((c) => c.id == widget.cardId).firstOrNull;
     return showPetCardShareSheet(
       context,
       petName: petName,
-      codeSeed: widget.cardId,
+      code: card == null ? petCardCode(widget.cardId) : displayCardCode(card),
       capture: _capture.capturePng,
       who: TextSpan(children: [
         TextSpan(text: '${_mode.label} 모드', style: const TextStyle(color: AppColors.primary600)),
@@ -64,7 +67,7 @@ class _PetCardDetailPageState extends ConsumerState<PetCardDetailPage> {
       toast.show('이미 대표 명함이에요', icon: RupIconName.star);
       return;
     }
-    await ref.read(petCardsProvider.notifier).setRepresentative(card);
+    if (!await succeeded(ref.read(petCardsProvider.notifier).setRepresentative(card))) return;
     toast.show('대표 명함으로 설정했어요', icon: RupIconName.star);
   }
 
@@ -86,7 +89,7 @@ class _PetCardDetailPageState extends ConsumerState<PetCardDetailPage> {
     if (!ok || !mounted) return;
     // 먼저 화면을 닫아 지워진 명함을 그리지 않게 한다
     context.pop();
-    await ref.read(petCardsProvider.notifier).delete(card.id);
+    if (!await succeeded(ref.read(petCardsProvider.notifier).delete(card.id))) return;
     ref.read(toastProvider.notifier).show('펫 명함을 삭제했어요');
   }
 
diff --git a/flutter/lib/features/pet_card/presentation/pages/pet_card_editor_page.dart b/flutter/lib/features/pet_card/presentation/pages/pet_card_editor_page.dart
index 84a4163..2c914c1 100644
--- a/flutter/lib/features/pet_card/presentation/pages/pet_card_editor_page.dart
+++ b/flutter/lib/features/pet_card/presentation/pages/pet_card_editor_page.dart
@@ -4,6 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 import 'package:image_picker/image_picker.dart';
+import 'package:tma_app/core/api/api_guard.dart';
 import 'package:tma_app/core/constants/app_colors.dart';
 import 'package:tma_app/core/constants/app_sizes.dart';
 import 'package:tma_app/core/router/app_routes.dart';
@@ -98,7 +99,7 @@ class _CardEditorState extends ConsumerState<_CardEditor> {
     final file = await _pickImage();
     if (file == null) return;
     final path = await ref.read(petPhotoStoreProvider).persist(file);
-    await ref.read(petListProvider.notifier).updatePet(pet.id, pet.withPhoto(path));
+    await succeeded(ref.read(petListProvider.notifier).updatePet(pet.id, pet.withPhoto(path)));
   }
 
   Future<void> _addBackground() async {
@@ -151,6 +152,9 @@ class _CardEditorState extends ConsumerState<_CardEditor> {
         // 만든 명함의 상세로 — 뒤로 가면 명함을 만들기 시작한 화면으로 돌아간다
         if (mounted) context.pushReplacement(AppRoutes.petCardDetail(card.id));
       }
+    } catch (e) {
+      // 실패 알림은 인터셉터가 띄웠다 — 꾸민 모양을 그대로 두고 다시 시도할 수 있게 한다
+      if (!isReportedApiFailure(e)) rethrow;
     } finally {
       if (mounted) setState(() => _saving = false);
     }
diff --git a/flutter/lib/features/pet_card/presentation/pages/pet_cards_page.dart b/flutter/lib/features/pet_card/presentation/pages/pet_cards_page.dart
index 74a7d79..725ae97 100644
--- a/flutter/lib/features/pet_card/presentation/pages/pet_cards_page.dart
+++ b/flutter/lib/features/pet_card/presentation/pages/pet_cards_page.dart
@@ -11,6 +11,7 @@ import 'package:tma_app/features/pet/domain/pet.dart';
 import 'package:tma_app/features/pet/presentation/providers/pet_providers.dart';
 import 'package:tma_app/features/pet/presentation/widgets/pet_picker.dart';
 import 'package:tma_app/features/pet_card/domain/pet_card.dart';
+import 'package:tma_app/features/pet_card/domain/pet_card_facts.dart';
 import 'package:tma_app/features/pet_card/presentation/providers/pet_card_providers.dart';
 import 'package:tma_app/features/pet_card/presentation/widgets/crown_mark.dart';
 import 'package:tma_app/features/pet_card/presentation/widgets/name_card.dart';
@@ -145,7 +146,7 @@ Future<void> sharePetCard(
   return showPetCardShareSheet(
     context,
     petName: pet.name,
-    codeSeed: card.id,
+    code: displayCardCode(card),
     capture: capture.capturePng,
     who: TextSpan(children: [
       TextSpan(text: pet.name, style: const TextStyle(color: AppColors.primary600)),
diff --git a/flutter/lib/features/pet_card/presentation/providers/pet_card_providers.dart b/flutter/lib/features/pet_card/presentation/providers/pet_card_providers.dart
index 4a8b439..4eae291 100644
--- a/flutter/lib/features/pet_card/presentation/providers/pet_card_providers.dart
+++ b/flutter/lib/features/pet_card/presentation/providers/pet_card_providers.dart
@@ -1,4 +1,5 @@
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:tma_app/core/api/session_store.dart';
 import 'package:tma_app/features/pet/domain/pet.dart';
 import 'package:tma_app/features/pet/presentation/providers/pet_providers.dart';
 import 'package:tma_app/features/pet_card/data/pet_card_repository.dart';
@@ -24,11 +25,10 @@ class PetCardNotifier extends AsyncNotifier<PetCardState> {
 
   @override
   Future<PetCardState> build() async {
-    final repo = ref.watch(petCardRepositoryProvider);
-    return PetCardState(
-      cards: await repo.fetchCards(),
-      representatives: await repo.fetchRepresentatives(),
-    );
+    // 회원이 바뀌면(로그인·로그아웃) 다시 읽는다
+    ref.watch(sessionEpochProvider);
+    final book = await ref.watch(petCardRepositoryProvider).fetch();
+    return PetCardState(cards: book.cards, representatives: book.representatives);
   }
 
   PetCardState get _current => state.value ?? const PetCardState(cards: [], representatives: {});
@@ -48,25 +48,22 @@ class PetCardNotifier extends AsyncNotifier<PetCardState> {
     _emit(_current.copyWith(cards: [for (final c in _current.cards) c.id == cardId ? card : c]));
   }
 
+  /// 명함 삭제 — 대표 명함이었으면 대표 지정도 함께 사라진다 (저장소가 정리한다)
   Future<void> delete(String cardId) async {
-    final card = _current.cards.where((c) => c.id == cardId).firstOrNull;
     await _repo.delete(cardId);
-    final reps = {..._current.representatives};
-    if (card != null && reps[card.petId] == cardId) {
-      reps.remove(card.petId);
-      await _repo.clearRepresentative(card.petId);
-    }
     _emit(PetCardState(
       cards: _current.cards.where((c) => c.id != cardId).toList(),
-      representatives: reps,
+      representatives: {..._current.representatives}..removeWhere((_, id) => id == cardId),
     ));
   }
 
-  /// 아이를 삭제하면 그 아이의 명함도 함께 지운다
+  /// 아이를 삭제하면 그 아이의 명함도 함께 지운다 (서버 모드는 서버가 이미 지웠다)
   Future<void> deleteForPet(String petId) async {
-    for (final card in _current.cards.where((c) => c.petId == petId).toList()) {
-      await delete(card.id);
-    }
+    await _repo.dropPet(petId);
+    _emit(PetCardState(
+      cards: _current.cards.where((c) => c.petId != petId).toList(),
+      representatives: {..._current.representatives}..remove(petId),
+    ));
   }
 
   Future<void> setRepresentative(PetCard card) async {
diff --git a/flutter/lib/features/pet_card/presentation/widgets/share_sheet.dart b/flutter/lib/features/pet_card/presentation/widgets/share_sheet.dart
index d0cb880..6dd2c75 100644
--- a/flutter/lib/features/pet_card/presentation/widgets/share_sheet.dart
+++ b/flutter/lib/features/pet_card/presentation/widgets/share_sheet.dart
@@ -8,7 +8,6 @@ import 'package:tma_app/core/constants/app_colors.dart';
 import 'package:tma_app/core/constants/app_sizes.dart';
 import 'package:tma_app/core/storage/album_saver.dart';
 import 'package:tma_app/core/theme/app_shadows.dart';
-import 'package:tma_app/features/pet_card/domain/pet_card_facts.dart';
 import 'package:tma_app/shared/widgets/blurred_modal.dart';
 import 'package:tma_app/shared/widgets/capture_boundary.dart';
 import 'package:tma_app/shared/widgets/icons/rup_icon.dart';
@@ -28,7 +27,7 @@ const double _kQrBadge = 54;
 Future<void> showPetCardShareSheet(
   BuildContext context, {
   required String petName,
-  required String codeSeed,
+  required String code,
   required InlineSpan who,
   required Future<Uint8List?> Function() capture,
 }) {
@@ -37,7 +36,7 @@ Future<void> showPetCardShareSheet(
     title: '$petName 펫 명함 공유',
     builder: (context) => _ShareBody(
       petName: petName,
-      code: petCardCode(codeSeed),
+      code: code,
       who: who,
       capture: capture,
     ),
diff --git a/flutter/test/api_pet_card_repository_test.dart b/flutter/test/api_pet_card_repository_test.dart
new file mode 100644
index 0000000..39006ba
--- /dev/null
+++ b/flutter/test/api_pet_card_repository_test.dart
@@ -0,0 +1,113 @@
+import 'dart:io';
+import 'dart:ui' show Color;
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:tma_app/core/api/file_uploader.dart';
+import 'package:tma_app/features/pet_card/data/api_pet_card_repository.dart';
+import 'package:tma_app/features/pet_card/domain/card_style.dart';
+
+import 'api_account_test.dart' show kPngBytes;
+import 'support/fake_api.dart';
+
+Map<String, Object?> _cardJson({
+  String id = 'c1',
+  String petId = 'p1',
+  bool isRepresentative = false,
+  String? nameBgAsset,
+  String? nameBgFileId,
+}) =>
+    {
+      'id': id,
+      'petId': petId,
+      'code': '0428-117',
+      'isRepresentative': isRepresentative,
+      'style': {
+        'tint': '#5AA0E0',
+        'tint2': '#9CCBF0',
+        'nameBg': null,
+        'nameBgAsset': nameBgAsset,
+        'nameBgFileId': nameBgFileId,
+        'textLight': true,
+        'scrim': true,
+        'scrimTone': 'dark',
+      },
+    };
+
+void main() {
+  late FakeApi api;
+  late ApiPetCardRepository repo;
+
+  setUp(() {
+    api = FakeApi();
+    repo = ApiPetCardRepository(dio: api.dio, session: api.session, uploader: FileUploader(api.dio, api.reported.add));
+  });
+
+  test('명함 목록에서 대표 명함을 아이별로 모으고, 서버가 발급한 코드를 담는다', () async {
+    api.on('GET', '/pet-cards', (r) => ok(page([
+          _cardJson(nameBgAsset: 'assets/svg/card_bg/bg_1.svg'),
+          _cardJson(id: 'c2', isRepresentative: true, nameBgFileId: 'f1'),
+          _cardJson(id: 'c3', petId: 'p2'),
+        ])));
+
+    final book = await repo.fetch();
+
+    expect(book.cards.map((c) => c.id), ['c1', 'c2', 'c3']);
+    expect(book.representatives, {'p1': 'c2'});
+    expect(book.cards.first.code, '0428-117');
+    expect(book.cards.first.style.nameBgImage, 'assets/svg/card_bg/bg_1.svg');
+    expect(book.cards[1].style.nameBgImage, 'server-file:f1');
+    expect(book.cards.first.style.scrimTone, ScrimTone.dark);
+  });
+
+  test('앱 그림 배경은 경로만 보내고 올리지 않는다', () async {
+    api.on('PUT', '/pet-cards/:id', (r) {
+      final style = r.json!['style'] as Map<String, dynamic>;
+      expect(style['nameBgAsset'], 'assets/svg/card_bg/bg_2.svg');
+      expect(style['nameBgFileId'], isNull);
+      return ok(_cardJson(nameBgAsset: 'assets/svg/card_bg/bg_2.svg'));
+    });
+
+    await repo.update('c1', CardStyle.initial().withBackgroundImage('assets/svg/card_bg/bg_2.svg'));
+
+    expect(api.sent('POST', '/files'), isEmpty);
+  });
+
+  test('기기 사진 배경은 올린 뒤 파일 id 로 보낸다', () async {
+    final dir = Directory.systemTemp.createTempSync('rup-card');
+    addTearDown(() => dir.deleteSync(recursive: true));
+    final photo = File('${dir.path}/bg.png')..writeAsBytesSync(kPngBytes);
+    api.on('POST', '/files', (r) => ok({'id': 'f7'}, status: 201));
+    api.on('POST', '/pet-cards', (r) {
+      expect(r.json!['petId'], 'p1');
+      final style = r.json!['style'] as Map<String, dynamic>;
+      expect(style['nameBgFileId'], 'f7');
+      expect(style['nameBgAsset'], isNull);
+      expect(style['tint'], '#FF9B6A');
+      return ok(_cardJson(nameBgFileId: 'f7'), status: 201);
+    });
+
+    final card = await repo.create('p1', CardStyle.forPet(const Color(0xFFFF9B6A)).withBackgroundImage(photo.path));
+
+    expect(card.style.nameBgImage, 'server-file:f7');
+  });
+
+  test('대표 명함은 아이의 하위 경로로 정하고 푼다', () async {
+    api.on('PUT', '/pets/:petId/representative-card', (r) {
+      expect(r.json, {'cardId': 'c1'});
+      return noContent;
+    });
+    api.on('DELETE', '/pets/:petId/representative-card', (r) => noContent);
+
+    await repo.setRepresentative('p1', 'c1');
+    await repo.clearRepresentative('p1');
+
+    expect(api.sent('PUT', '/pets/p1/representative-card'), hasLength(1));
+    expect(api.sent('DELETE', '/pets/p1/representative-card'), hasLength(1));
+  });
+
+  test('아이를 지울 때 명함 정리는 서버가 이미 했다', () async {
+    await repo.dropPet('p1');
+
+    expect(api.requests, isEmpty);
+  });
+}
diff --git a/flutter/test/pet_card_domain_test.dart b/flutter/test/pet_card_domain_test.dart
index 7f13cf3..f4053c6 100644
--- a/flutter/test/pet_card_domain_test.dart
+++ b/flutter/test/pet_card_domain_test.dart
@@ -113,21 +113,50 @@ void main() {
       await repo.create('pet-1', CardStyle.initial());
       await repo.update(a.id, CardStyle.initial().withTextLight(true));
 
-      var cards = await repo.fetchCards();
+      var cards = (await repo.fetch()).cards;
       expect(cards, hasLength(2));
       expect(cards.first.style.textLight, isTrue);
 
       await repo.delete(a.id);
-      cards = await repo.fetchCards();
+      cards = (await repo.fetch()).cards;
       expect(cards.map((c) => c.id), isNot(contains(a.id)));
     });
 
     test('대표 명함을 아이별로 기억하고 지울 수 있다', () async {
       final a = await repo.create('pet-1', CardStyle.initial());
       await repo.setRepresentative('pet-1', a.id);
-      expect(await repo.fetchRepresentatives(), {'pet-1': a.id});
+      expect((await repo.fetch()).representatives, {'pet-1': a.id});
       await repo.clearRepresentative('pet-1');
-      expect(await repo.fetchRepresentatives(), isEmpty);
+      expect((await repo.fetch()).representatives, isEmpty);
+    });
+
+    test('명함을 지우면 그 명함을 가리키던 대표 지정도 사라진다', () async {
+      final a = await repo.create('pet-1', CardStyle.initial());
+      await repo.setRepresentative('pet-1', a.id);
+
+      await repo.delete(a.id);
+
+      expect((await repo.fetch()).representatives, isEmpty);
+    });
+
+    test('아이를 지우면 그 아이의 명함과 대표 지정을 모두 지운다', () async {
+      final a = await repo.create('pet-1', CardStyle.initial());
+      await repo.create('pet-2', CardStyle.initial());
+      await repo.setRepresentative('pet-1', a.id);
+
+      await repo.dropPet('pet-1');
+
+      final book = await repo.fetch();
+      expect(book.cards.map((c) => c.petId), ['pet-2']);
+      expect(book.representatives, isEmpty);
+    });
+
+    test('명함 코드는 서버가 발급한 값, 없으면 명함 id 로 만든다', () {
+      final local = PetCard(id: 'c1', petId: 'p1', style: CardStyle.initial());
+      const fromServer = PetCard(id: 'c1', petId: 'p1', style: CardStyle(tint: Color(0xFFFF9B6A), tint2: Color(0xFFFF9B6A)), code: '0428-117');
+
+      expect(displayCardCode(local), petCardCode('c1'));
+      expect(displayCardCode(fromServer), '0428-117');
     });
 
     test('명함 JSON 을 그대로 되살릴 수 있다', () {