diff --git a/backend/src/app.module.ts b/backend/src/app.module.ts
index 56bb825..36c5ab8 100644
--- a/backend/src/app.module.ts
+++ b/backend/src/app.module.ts
@@ -13,6 +13,7 @@ import { AuthModule } from '@/modules/auth/auth.module';
 import { DiaryModule } from '@/modules/diary/diary.module';
 import { HealthModule } from '@/modules/health/health.module';
 import { PetModule } from '@/modules/pet/pet.module';
+import { PetCardModule } from '@/modules/pet-card/pet-card.module';
 import { ScheduleModule } from '@/modules/schedule/schedule.module';
 import { UploadModule } from '@/modules/upload/upload.module';
 import { UserModule } from '@/modules/user/user.module';
@@ -70,6 +71,7 @@ const THROTTLE_DEFAULT_LIMIT = 100; // 구간당 IP별 최대 요청 수
     PetModule,
     ScheduleModule,
     DiaryModule,
+    PetCardModule,
   ],
   providers: [
     ShutdownLogger,
diff --git a/backend/src/common/errors/error-codes.ts b/backend/src/common/errors/error-codes.ts
index f26d906..8e7c99c 100644
--- a/backend/src/common/errors/error-codes.ts
+++ b/backend/src/common/errors/error-codes.ts
@@ -83,6 +83,11 @@ const DOMAIN_ERROR_CODES = {
     status: HttpStatus.CONFLICT,
     message: '오늘 기록은 이미 남겼어요. 내일 다시 작성할 수 있어요.',
   },
+  // 펫 명함 — 한 사람이 최대 10장
+  CARD_001: {
+    status: HttpStatus.CONFLICT,
+    message: '펫 명함은 최대 10장까지 만들 수 있어요.',
+  },
 } as const satisfies Record<string, ErrorCodeDefinition>;
 
 export const ERROR_CODES = {
diff --git a/backend/src/migrations/1791707889244-AddPetCards.ts b/backend/src/migrations/1791707889244-AddPetCards.ts
new file mode 100644
index 0000000..b2735f9
--- /dev/null
+++ b/backend/src/migrations/1791707889244-AddPetCards.ts
@@ -0,0 +1,45 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class AddPetCards1791707889244 implements MigrationInterface {
+  name = 'AddPetCards1791707889244';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `CREATE TABLE "pet_cards" ("id" uuid NOT NULL DEFAULT uuid_generate_v4(), "owner_id" uuid NOT NULL, "pet_id" uuid NOT NULL, "code" character varying(8) NOT NULL, "tint" character varying(7) NOT NULL, "tint2" character varying(7) NOT NULL, "name_bg" character varying(7), "name_bg_asset" character varying(120), "name_bg_file_id" uuid, "text_light" boolean NOT NULL DEFAULT false, "scrim" boolean NOT NULL DEFAULT false, "scrim_tone" character varying(5) NOT NULL DEFAULT 'light', "is_representative" boolean NOT NULL DEFAULT false, "created_at" TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(), "updated_at" TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(), CONSTRAINT "UQ_b0cdb9b6d8843b8ccdd8189475e" UNIQUE ("code"), CONSTRAINT "PK_cb97f59edc0aab4f315acd5c1fa" PRIMARY KEY ("id"))`,
+    );
+    await queryRunner.query(
+      `CREATE INDEX "IDX_71ffe780c984a78a864a07465f" ON "pet_cards" ("owner_id") `,
+    );
+    await queryRunner.query(
+      `CREATE UNIQUE INDEX "UQ_pet_cards_representative" ON "pet_cards" ("pet_id") WHERE "is_representative"`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "pet_cards" ADD CONSTRAINT "FK_71ffe780c984a78a864a07465f8" FOREIGN KEY ("owner_id") REFERENCES "users"("id") ON DELETE CASCADE ON UPDATE NO ACTION`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "pet_cards" ADD CONSTRAINT "FK_5d2fc9ac2b34f34dfaca776fc7f" FOREIGN KEY ("pet_id") REFERENCES "pets"("id") ON DELETE CASCADE ON UPDATE NO ACTION`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "pet_cards" ADD CONSTRAINT "FK_672dc0c78f4a9ffde6239f1db86" FOREIGN KEY ("name_bg_file_id") REFERENCES "files"("id") ON DELETE NO ACTION ON UPDATE NO ACTION`,
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "pet_cards" DROP CONSTRAINT "FK_672dc0c78f4a9ffde6239f1db86"`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "pet_cards" DROP CONSTRAINT "FK_5d2fc9ac2b34f34dfaca776fc7f"`,
+    );
+    await queryRunner.query(
+      `ALTER TABLE "pet_cards" DROP CONSTRAINT "FK_71ffe780c984a78a864a07465f8"`,
+    );
+    await queryRunner.query(
+      `DROP INDEX "public"."UQ_pet_cards_representative"`,
+    );
+    await queryRunner.query(
+      `DROP INDEX "public"."IDX_71ffe780c984a78a864a07465f"`,
+    );
+    await queryRunner.query(`DROP TABLE "pet_cards"`);
+  }
+}
diff --git a/backend/src/modules/pet-card/card-code.spec.ts b/backend/src/modules/pet-card/card-code.spec.ts
new file mode 100644
index 0000000..478f1aa
--- /dev/null
+++ b/backend/src/modules/pet-card/card-code.spec.ts
@@ -0,0 +1,14 @@
+import { formatCardCode, randomCardCode } from './card-code';
+
+describe('명함 코드', () => {
+  it('7자리를 0000-000 형식으로 쓴다', () => {
+    expect(formatCardCode(4_281_170)).toBe('4281-170');
+    expect(formatCardCode(42)).toBe('0000-042');
+  });
+
+  it('무작위 코드도 같은 형식이다', () => {
+    for (let i = 0; i < 20; i += 1) {
+      expect(randomCardCode()).toMatch(/^\d{4}-\d{3}$/);
+    }
+  });
+});
diff --git a/backend/src/modules/pet-card/card-code.ts b/backend/src/modules/pet-card/card-code.ts
new file mode 100644
index 0000000..5a784d4
--- /dev/null
+++ b/backend/src/modules/pet-card/card-code.ts
@@ -0,0 +1,17 @@
+import { randomInt } from 'crypto';
+
+/** 명함 코드 자릿수 — "0000-000" (앱이 보여 주는 형식) */
+const CODE_DIGITS = 7;
+const CODE_SPACE = 10 ** CODE_DIGITS;
+const CODE_HEAD = 4;
+
+/** 0 ~ 9,999,999 → "0000-000" */
+export function formatCardCode(value: number): string {
+  const digits = String(value % CODE_SPACE).padStart(CODE_DIGITS, '0');
+  return `${digits.slice(0, CODE_HEAD)}-${digits.slice(CODE_HEAD)}`;
+}
+
+/** 새 명함 코드 — 추측하기 어렵게 무작위로 뽑는다 (겹치면 호출한 쪽이 다시 뽑는다) */
+export function randomCardCode(): string {
+  return formatCardCode(randomInt(0, CODE_SPACE));
+}
diff --git a/backend/src/modules/pet-card/dto/pet-card.dto.ts b/backend/src/modules/pet-card/dto/pet-card.dto.ts
new file mode 100644
index 0000000..d04a04c
--- /dev/null
+++ b/backend/src/modules/pet-card/dto/pet-card.dto.ts
@@ -0,0 +1,168 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { Type } from 'class-transformer';
+import {
+  IsBoolean,
+  IsIn,
+  IsOptional,
+  IsUUID,
+  Matches,
+  ValidateNested,
+} from 'class-validator';
+
+import { IsHexColor } from '@/common/validators';
+import { SCRIM_TONES } from '../entities/pet-card.entity';
+import type { PetCard, ScrimTone } from '../entities/pet-card.entity';
+
+/** 앱에 들어 있는 배경 그림 경로 — 경로 탈출·다른 형식을 막는다 */
+const ASSET_PATH_PATTERN =
+  /^assets\/[A-Za-z0-9_-]+(\/[A-Za-z0-9_-]+)*\.(png|jpg|jpeg|webp)$/;
+
+/** 명함 꾸미기 값 (앱의 CardStyle) — 배경은 색·그림·사진 중 하나만 */
+export class CardStyleDto {
+  @ApiProperty({
+    description: '상단 그라데이션 첫 색 (#RRGGBB)',
+    example: '#FF9B6A',
+  })
+  @IsHexColor()
+  tint!: string;
+
+  @ApiProperty({
+    description: '상단 그라데이션 둘째 색 (#RRGGBB)',
+    example: '#FFC59B',
+  })
+  @IsHexColor()
+  tint2!: string;
+
+  @ApiPropertyOptional({
+    description: '배경색 (#RRGGBB) — 없으면 흰색',
+    nullable: true,
+    type: String,
+  })
+  @IsOptional()
+  @IsHexColor()
+  nameBg?: string | null;
+
+  @ApiPropertyOptional({
+    description: '앱에 들어 있는 배경 그림 경로 (assets/…)',
+    nullable: true,
+    type: String,
+  })
+  @IsOptional()
+  @Matches(ASSET_PATH_PATTERN, {
+    message: '배경 그림 정보가 올바르지 않습니다.',
+  })
+  nameBgAsset?: string | null;
+
+  @ApiPropertyOptional({
+    description: '배경 사진 파일 ID (POST /api/files 로 올린 이미지)',
+    nullable: true,
+    type: String,
+  })
+  @IsOptional()
+  @IsUUID('4', { message: '사진 정보가 올바르지 않습니다.' })
+  nameBgFileId?: string | null;
+
+  @ApiProperty({ description: '밝은 글자 (어두운 배경용)', example: false })
+  @IsBoolean()
+  textLight!: boolean;
+
+  @ApiProperty({ description: '글자 뒤 막 덮기', example: false })
+  @IsBoolean()
+  scrim!: boolean;
+
+  @ApiProperty({ enum: SCRIM_TONES, example: 'light' })
+  @IsIn(SCRIM_TONES, { message: '막 색이 올바르지 않습니다.' })
+  scrimTone!: ScrimTone;
+}
+
+/** 새 명함 */
+export class CreatePetCardDto {
+  @ApiProperty({ description: '명함을 만들 아이 ID' })
+  @IsUUID('4', { message: '아이 정보가 올바르지 않습니다.' })
+  petId!: string;
+
+  @ApiProperty({ type: CardStyleDto })
+  @ValidateNested()
+  @Type(() => CardStyleDto)
+  style!: CardStyleDto;
+}
+
+/** 명함 꾸미기 바꾸기 — 꾸미기 값을 통째로 바꾼다 */
+export class UpdatePetCardDto {
+  @ApiProperty({ type: CardStyleDto })
+  @ValidateNested()
+  @Type(() => CardStyleDto)
+  style!: CardStyleDto;
+}
+
+/** 대표 명함 지정 */
+export class SetRepresentativeDto {
+  @ApiProperty({ description: '대표로 둘 명함 ID (그 아이의 명함이어야 한다)' })
+  @IsUUID('4', { message: '명함 정보가 올바르지 않습니다.' })
+  cardId!: string;
+}
+
+/** 명함 꾸미기 응답 */
+export class CardStyleResponseDto {
+  @ApiProperty() tint!: string;
+  @ApiProperty() tint2!: string;
+  @ApiProperty({ nullable: true, type: String }) nameBg!: string | null;
+  @ApiProperty({ nullable: true, type: String }) nameBgAsset!: string | null;
+  @ApiProperty({ nullable: true, type: String }) nameBgFileId!: string | null;
+  @ApiProperty() textLight!: boolean;
+  @ApiProperty() scrim!: boolean;
+  @ApiProperty({ enum: SCRIM_TONES }) scrimTone!: ScrimTone;
+}
+
+/** 펫 명함 응답 (앱의 PetCard) */
+export class PetCardResponseDto {
+  @ApiProperty() id!: string;
+  @ApiProperty() petId!: string;
+
+  @ApiProperty({ description: '명함 코드', example: '0428-117' })
+  code!: string;
+
+  @ApiProperty({ type: CardStyleResponseDto })
+  style!: CardStyleResponseDto;
+
+  @ApiProperty({ description: '아이의 대표 명함인지' })
+  isRepresentative!: boolean;
+
+  static from(card: PetCard): PetCardResponseDto {
+    return {
+      id: card.id,
+      petId: card.petId,
+      code: card.code,
+      style: {
+        tint: card.tint,
+        tint2: card.tint2,
+        nameBg: card.nameBg,
+        nameBgAsset: card.nameBgAsset,
+        nameBgFileId: card.nameBgFileId,
+        textLight: card.textLight,
+        scrim: card.scrim,
+        scrimTone: card.scrimTone,
+      },
+      isRepresentative: card.isRepresentative,
+    };
+  }
+}
+
+/**
+ * 꾸미기 DTO → 컬럼 값. 배경은 하나만 남긴다 — 사진 > 그림 > 색 순으로 우선한다
+ * (앱도 하나를 고르면 나머지를 비운다).
+ */
+export function toStyleColumns(style: CardStyleDto) {
+  const file = style.nameBgFileId ?? null;
+  const asset = file ? null : (style.nameBgAsset ?? null);
+  return {
+    tint: style.tint,
+    tint2: style.tint2,
+    nameBg: file || asset ? null : (style.nameBg ?? null),
+    nameBgAsset: asset,
+    nameBgFileId: file,
+    textLight: style.textLight,
+    scrim: style.scrim,
+    scrimTone: style.scrimTone,
+  };
+}
diff --git a/backend/src/modules/pet-card/entities/pet-card.entity.ts b/backend/src/modules/pet-card/entities/pet-card.entity.ts
new file mode 100644
index 0000000..0f884a9
--- /dev/null
+++ b/backend/src/modules/pet-card/entities/pet-card.entity.ts
@@ -0,0 +1,101 @@
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  Index,
+  JoinColumn,
+  ManyToOne,
+  PrimaryGeneratedColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+
+import { Pet } from '@/modules/pet/entities/pet.entity';
+import { StoredFile } from '@/modules/upload/entities/stored-file.entity';
+import { User } from '@/modules/user/entities/user.entity';
+
+/** 한 사람이 만들 수 있는 펫 명함 수 — 앱의 kMaxPetCards */
+export const MAX_PET_CARDS = 10;
+
+/** 글자 뒤에 덮는 막의 색 (앱의 ScrimTone) */
+export const SCRIM_TONES = ['light', 'dark'] as const;
+export type ScrimTone = (typeof SCRIM_TONES)[number];
+
+/**
+ * 펫 명함 — 어느 아이의 명함인지 + 꾸미기 값(앱의 CardStyle).
+ * 이름·품종 등 내용은 아이 정보를 그대로 쓰고 모양만 저장한다.
+ * 배경은 색(nameBg) · 앱에 들어 있는 그림(nameBgAsset) · 올린 사진(nameBgFileId) 중 하나만 쓴다.
+ */
+@Entity('pet_cards')
+// 아이마다 대표 명함은 하나
+@Index('UQ_pet_cards_representative', ['petId'], {
+  unique: true,
+  where: '"is_representative"',
+})
+export class PetCard {
+  @PrimaryGeneratedColumn('uuid')
+  id!: string;
+
+  @ManyToOne(() => User, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'owner_id' })
+  owner?: User;
+
+  @Index()
+  @Column({ type: 'uuid' })
+  ownerId!: string;
+
+  /** 아이를 지우면 그 아이의 명함도 지운다 */
+  @ManyToOne(() => Pet, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'pet_id' })
+  pet?: Pet;
+
+  @Column({ type: 'uuid' })
+  petId!: string;
+
+  /** 명함 코드 "0000-000" — 서버가 발급한다. 명함 받기에서 이 코드로 찾는다 */
+  @Column({ type: 'varchar', length: 8, unique: true })
+  code!: string;
+
+  /** 카드 상단 그라데이션 두 색 `#RRGGBB` */
+  @Column({ type: 'varchar', length: 7 })
+  tint!: string;
+
+  @Column({ type: 'varchar', length: 7 })
+  tint2!: string;
+
+  /** 배경색 — null 이면 흰색 */
+  @Column({ type: 'varchar', length: 7, nullable: true })
+  nameBg!: string | null;
+
+  /** 앱에 들어 있는 배경 그림 경로 (assets/…) */
+  @Column({ type: 'varchar', length: 120, nullable: true })
+  nameBgAsset!: string | null;
+
+  /** 올린 배경 사진 — 참조 중인 파일은 지울 수 없게 둔다 (UploadService.releaseIfUnused) */
+  @ManyToOne(() => StoredFile, { nullable: true, onDelete: 'NO ACTION' })
+  @JoinColumn({ name: 'name_bg_file_id' })
+  nameBgFile?: StoredFile | null;
+
+  @Column({ type: 'uuid', nullable: true })
+  nameBgFileId!: string | null;
+
+  /** 밝은 글자 (어두운 배경용) */
+  @Column({ type: 'boolean', default: false })
+  textLight!: boolean;
+
+  /** 글자 뒤에 은은한 막을 덮을지 */
+  @Column({ type: 'boolean', default: false })
+  scrim!: boolean;
+
+  @Column({ type: 'varchar', length: 5, default: 'light' })
+  scrimTone!: ScrimTone;
+
+  /** 아이의 대표 명함인지 */
+  @Column({ type: 'boolean', default: false })
+  isRepresentative!: boolean;
+
+  @CreateDateColumn({ type: 'timestamptz' })
+  createdAt!: Date;
+
+  @UpdateDateColumn({ type: 'timestamptz' })
+  updatedAt!: Date;
+}
diff --git a/backend/src/modules/pet-card/pet-card.module.ts b/backend/src/modules/pet-card/pet-card.module.ts
new file mode 100644
index 0000000..939c3f0
--- /dev/null
+++ b/backend/src/modules/pet-card/pet-card.module.ts
@@ -0,0 +1,18 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+
+import { PetModule } from '@/modules/pet/pet.module';
+import { UploadModule } from '@/modules/upload/upload.module';
+import { PetCard } from './entities/pet-card.entity';
+import { PetCardService } from './pet-card.service';
+import {
+  PetCardsController,
+  RepresentativeCardController,
+} from './pet-cards.controller';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([PetCard]), PetModule, UploadModule],
+  controllers: [PetCardsController, RepresentativeCardController],
+  providers: [PetCardService],
+})
+export class PetCardModule {}
diff --git a/backend/src/modules/pet-card/pet-card.service.spec.ts b/backend/src/modules/pet-card/pet-card.service.spec.ts
new file mode 100644
index 0000000..fe77d58
--- /dev/null
+++ b/backend/src/modules/pet-card/pet-card.service.spec.ts
@@ -0,0 +1,98 @@
+import { DataSource, EntityManager, Repository } from 'typeorm';
+
+import { PetService } from '@/modules/pet/pet.service';
+import { UploadService } from '@/modules/upload/upload.service';
+import { CardStyleDto, toStyleColumns } from './dto/pet-card.dto';
+import { PetCard } from './entities/pet-card.entity';
+import { PetCardService } from './pet-card.service';
+
+const style = (overrides: Partial<CardStyleDto> = {}): CardStyleDto => ({
+  tint: '#FF9B6A',
+  tint2: '#FFC59B',
+  textLight: false,
+  scrim: false,
+  scrimTone: 'light',
+  ...overrides,
+});
+
+describe('toStyleColumns', () => {
+  it('배경은 하나만 남긴다 — 사진 > 그림 > 색', () => {
+    expect(
+      toStyleColumns(
+        style({
+          nameBg: '#FFFFFF',
+          nameBgAsset: 'assets/a.png',
+          nameBgFileId: 'f',
+        }),
+      ),
+    ).toMatchObject({ nameBg: null, nameBgAsset: null, nameBgFileId: 'f' });
+    expect(
+      toStyleColumns(style({ nameBg: '#FFFFFF', nameBgAsset: 'assets/a.png' })),
+    ).toMatchObject({ nameBg: null, nameBgAsset: 'assets/a.png' });
+    expect(toStyleColumns(style({ nameBg: '#FFFFFF' }))).toMatchObject({
+      nameBg: '#FFFFFF',
+      nameBgAsset: null,
+      nameBgFileId: null,
+    });
+  });
+});
+
+describe('PetCardService', () => {
+  const cards = { findOneBy: jest.fn(), update: jest.fn() };
+  const manager = { update: jest.fn(), find: jest.fn() };
+  const dataSource = {
+    transaction: jest.fn((work: (m: EntityManager) => Promise<unknown>) =>
+      work(manager as unknown as EntityManager),
+    ),
+  };
+  const pets = { registerListener: jest.fn(), findOwned: jest.fn() };
+  const uploads = { assertOwnedImage: jest.fn(), releaseIfUnused: jest.fn() };
+  const service = new PetCardService(
+    cards as unknown as Repository<PetCard>,
+    dataSource as unknown as DataSource,
+    pets as unknown as PetService,
+    uploads as unknown as UploadService,
+  );
+
+  beforeEach(() => jest.clearAllMocks());
+
+  it('다른 아이의 명함은 대표로 정할 수 없다 (VAL_001)', async () => {
+    cards.findOneBy.mockResolvedValue({ id: 'c1', petId: 'pet-b' });
+
+    await expect(
+      service.setRepresentative('o', 'pet-a', 'c1'),
+    ).rejects.toMatchObject({ code: 'VAL_001' });
+    expect(dataSource.transaction).not.toHaveBeenCalled();
+  });
+
+  it('대표를 바꾸면 그 아이의 기존 대표를 먼저 푼다', async () => {
+    cards.findOneBy.mockResolvedValue({ id: 'c1', petId: 'pet-a' });
+
+    await service.setRepresentative('o', 'pet-a', 'c1');
+
+    expect(manager.update).toHaveBeenNthCalledWith(
+      1,
+      PetCard,
+      { petId: 'pet-a', isRepresentative: true },
+      { isRepresentative: false },
+    );
+    expect(manager.update).toHaveBeenNthCalledWith(
+      2,
+      PetCard,
+      { id: 'c1' },
+      { isRepresentative: true },
+    );
+  });
+
+  it('아이를 지울 때 그 아이 명함의 배경 사진을 정리 대상으로 돌려준다', async () => {
+    manager.find.mockResolvedValue([{ nameBgFileId: 'bg-1' }]);
+
+    await expect(
+      service.onPetDeleting({
+        ownerId: 'o',
+        petId: 'pet-a',
+        manager: manager as unknown as EntityManager,
+      }),
+    ).resolves.toEqual(['bg-1']);
+  });
+});
diff --git a/backend/src/modules/pet-card/pet-card.service.ts b/backend/src/modules/pet-card/pet-card.service.ts
new file mode 100644
index 0000000..02876ee
--- /dev/null
+++ b/backend/src/modules/pet-card/pet-card.service.ts
@@ -0,0 +1,194 @@
+import { Injectable, OnModuleInit } from '@nestjs/common';
+import { InjectDataSource, InjectRepository } from '@nestjs/typeorm';
+import { DataSource, IsNull, Not, Repository } from 'typeorm';
+
+import { keysetPaginate, mapPage } from '@/common/dto/keyset-pagination';
+import {
+  CursorPaginationQueryDto,
+  PaginatedResult,
+} from '@/common/dto/pagination.dto';
+import { BusinessException } from '@/common/errors/business.exception';
+import {
+  PetLifecycleEvent,
+  PetLifecycleListener,
+} from '@/modules/pet/pet-lifecycle';
+import { PetService } from '@/modules/pet/pet.service';
+import { UploadService } from '@/modules/upload/upload.service';
+import { isUniqueViolation } from '@/shared/utils/db-error';
+import { randomCardCode } from './card-code';
+import {
+  CreatePetCardDto,
+  PetCardResponseDto,
+  UpdatePetCardDto,
+  toStyleColumns,
+} from './dto/pet-card.dto';
+import { MAX_PET_CARDS, PetCard } from './entities/pet-card.entity';
+
+/** 명함 코드가 겹치면 다시 뽑는 횟수 — 천만 개 중에서 뽑으므로 거의 겹치지 않는다 */
+const CODE_RETRY = 5;
+
+// 펫 명함 — 만들기·꾸미기·삭제·대표 명함
+@Injectable()
+export class PetCardService implements OnModuleInit, PetLifecycleListener {
+  constructor(
+    @InjectRepository(PetCard)
+    private readonly cards: Repository<PetCard>,
+    @InjectDataSource()
+    private readonly dataSource: DataSource,
+    private readonly pets: PetService,
+    private readonly uploads: UploadService,
+  ) {}
+
+  onModuleInit(): void {
+    this.pets.registerListener(this);
+  }
+
+  /** 내 명함 목록 (만든 순) — 추억 보관함의 아이 명함도 함께 온다 */
+  async list(
+    ownerId: string,
+    query: CursorPaginationQueryDto,
+  ): Promise<PaginatedResult<PetCardResponseDto>> {
+    const qb = this.cards
+      .createQueryBuilder('card')
+      .where('card.owner_id = :ownerId', { ownerId });
+    const page = await keysetPaginate(
+      qb,
+      [
+        {
+          column: 'card.created_at',
+          cast: 'timestamptz',
+          read: (c) => c.createdAt.toISOString(),
+        },
+        { column: 'card.id', cast: 'uuid', read: (c) => c.id },
+      ],
+      query,
+    );
+    return mapPage(page, (c) => PetCardResponseDto.from(c));
+  }
+
+  /** 새 명함 — 최대 10장 (CARD_001). 코드는 서버가 발급한다 */
+  async create(
+    ownerId: string,
+    dto: CreatePetCardDto,
+  ): Promise<PetCardResponseDto> {
+    await this.pets.findOwned(ownerId, dto.petId);
+    await this.uploads.assertOwnedImage(dto.style.nameBgFileId, ownerId);
+
+    for (let attempt = 1; ; attempt += 1) {
+      try {
+        return await this.insertCard(ownerId, dto);
+      } catch (error) {
+        // 코드가 겹쳤으면 다시 뽑는다 (그 밖의 유니크 위반은 없다)
+        if (!isUniqueViolation(error) || attempt >= CODE_RETRY) throw error;
+      }
+    }
+  }
+
+  async update(
+    ownerId: string,
+    cardId: string,
+    dto: UpdatePetCardDto,
+  ): Promise<PetCardResponseDto> {
+    const card = await this.findOwnedCard(ownerId, cardId);
+    await this.uploads.assertOwnedImage(dto.style.nameBgFileId, ownerId);
+
+    const previousBg = card.nameBgFileId;
+    const saved = await this.cards.save(
+      this.cards.merge(card, toStyleColumns(dto.style)),
+    );
+    if (previousBg !== saved.nameBgFileId) {
+      await this.uploads.releaseIfUnused([previousBg]);
+    }
+    return PetCardResponseDto.from(saved);
+  }
+
+  /** 명함 삭제 — 대표 명함이었으면 대표 지정도 함께 사라진다 */
+  async remove(ownerId: string, cardId: string): Promise<void> {
+    const card = await this.findOwnedCard(ownerId, cardId);
+    await this.cards.delete({ id: card.id });
+    await this.uploads.releaseIfUnused([card.nameBgFileId]);
+  }
+
+  /** 아이의 대표 명함 정하기 — 그 아이의 명함이어야 한다 */
+  async setRepresentative(
+    ownerId: string,
+    petId: string,
+    cardId: string,
+  ): Promise<void> {
+    const card = await this.findOwnedCard(ownerId, cardId);
+    if (card.petId !== petId) {
+      throw new BusinessException('VAL_001', {
+        context: { reason: 'card-of-other-pet', petId, cardId },
+      });
+    }
+
+    await this.dataSource.transaction(async (manager) => {
+      await manager.update(
+        PetCard,
+        { petId, isRepresentative: true },
+        { isRepresentative: false },
+      );
+      await manager.update(PetCard, { id: cardId }, { isRepresentative: true });
+    });
+  }
+
+  /** 대표 명함 지정 풀기 — 앱은 그 아이의 첫 명함을 보여 준다 */
+  async clearRepresentative(ownerId: string, petId: string): Promise<void> {
+    await this.pets.findOwned(ownerId, petId);
+    await this.cards.update(
+      { petId, ownerId, isRepresentative: true },
+      { isRepresentative: false },
+    );
+  }
+
+  /** 아이를 지우면 명함은 FK 로 함께 지워진다 — 배경 사진은 커밋 뒤 정리하도록 돌려준다 */
+  async onPetDeleting({
+    petId,
+    manager,
+  }: PetLifecycleEvent): Promise<Array<string | null>> {
+    const withPhoto = await manager.find(PetCard, {
+      where: { petId, nameBgFileId: Not(IsNull()) },
+      select: { nameBgFileId: true },
+    });
+    return withPhoto.map((c) => c.nameBgFileId);
+  }
+
+  private async insertCard(
+    ownerId: string,
+    dto: CreatePetCardDto,
+  ): Promise<PetCardResponseDto> {
+    return this.dataSource.transaction(async (manager) => {
+      // 동시에 만들어 한도를 넘지 않도록 회원의 명함을 잠그고 센다
+      const existing = await manager.find(PetCard, {
+        where: { ownerId },
+        select: { id: true },
+        lock: { mode: 'pessimistic_write' },
+      });
+      if (existing.length >= MAX_PET_CARDS) {
+        throw new BusinessException('CARD_001', {
+          context: { count: existing.length },
+        });
+      }
+
+      const card = await manager.save(
+        manager.create(PetCard, {
+          ownerId,
+          petId: dto.petId,
+          code: randomCardCode(),
+          ...toStyleColumns(dto.style),
+          isRepresentative: false,
+        }),
+      );
+      return PetCardResponseDto.from(card);
+    });
+  }
+
+  private async findOwnedCard(
+    ownerId: string,
+    cardId: string,
+  ): Promise<PetCard> {
+    const card = await this.cards.findOneBy({ id: cardId, ownerId });
+    if (!card) throw new BusinessException('RES_001', { context: { cardId } });
+    return card;
+  }
+}
diff --git a/backend/src/modules/pet-card/pet-cards.controller.ts b/backend/src/modules/pet-card/pet-cards.controller.ts
new file mode 100644
index 0000000..c523219
--- /dev/null
+++ b/backend/src/modules/pet-card/pet-cards.controller.ts
@@ -0,0 +1,138 @@
+import {
+  Body,
+  Controller,
+  Delete,
+  Get,
+  HttpCode,
+  HttpStatus,
+  Param,
+  ParseUUIDPipe,
+  Post,
+  Put,
+  Query,
+} from '@nestjs/common';
+import {
+  ApiBearerAuth,
+  ApiNoContentResponse,
+  ApiOperation,
+  ApiTags,
+} from '@nestjs/swagger';
+
+import {
+  ApiErrorResponse,
+  ApiPaginatedResponse,
+  ApiStandardResponse,
+} from '@/common/decorators/api-standard-response.decorator';
+import { CurrentUser } from '@/common/decorators/current-user.decorator';
+import type { AuthUser } from '@/common/decorators/current-user.decorator';
+import { SkipTransform } from '@/common/decorators/skip-transform.decorator';
+import {
+  CursorPaginationQueryDto,
+  PaginatedResult,
+} from '@/common/dto/pagination.dto';
+import {
+  CreatePetCardDto,
+  PetCardResponseDto,
+  SetRepresentativeDto,
+  UpdatePetCardDto,
+} from './dto/pet-card.dto';
+import { PetCardService } from './pet-card.service';
+
+// 펫 명함 — 라우팅과 입출력만 담당, 비즈니스 로직은 모두 service 위임
+@ApiTags('PetCard')
+@ApiBearerAuth()
+@ApiErrorResponse('AUTH_001', '로그인 필요')
+@Controller('pet-cards')
+export class PetCardsController {
+  constructor(private readonly cards: PetCardService) {}
+
+  @Get()
+  @ApiOperation({ summary: '내 명함 목록 (만든 순, 커서 페이지네이션)' })
+  @ApiPaginatedResponse(PetCardResponseDto, '명함 목록')
+  @ApiErrorResponse('VAL_001', '페이지네이션 파라미터 오류')
+  list(
+    @CurrentUser() user: AuthUser,
+    @Query() query: CursorPaginationQueryDto,
+  ): Promise<PaginatedResult<PetCardResponseDto>> {
+    return this.cards.list(user.userId, query);
+  }
+
+  @Post()
+  @ApiOperation({ summary: '새 명함 (최대 10장, 코드는 서버가 발급)' })
+  @ApiStandardResponse(PetCardResponseDto, {
+    status: 201,
+    description: '만든 명함',
+  })
+  @ApiErrorResponse('CARD_001', '명함이 가득 참 (최대 10장)')
+  @ApiErrorResponse('RES_001', '아이를 찾을 수 없음')
+  @ApiErrorResponse('VAL_001', '입력값 검증 실패')
+  create(
+    @CurrentUser() user: AuthUser,
+    @Body() dto: CreatePetCardDto,
+  ): Promise<PetCardResponseDto> {
+    return this.cards.create(user.userId, dto);
+  }
+
+  @Put(':id')
+  @ApiOperation({ summary: '명함 꾸미기 바꾸기' })
+  @ApiStandardResponse(PetCardResponseDto, { description: '바꾼 명함' })
+  @ApiErrorResponse('RES_001', '명함을 찾을 수 없음')
+  @ApiErrorResponse('VAL_001', '입력값 검증 실패')
+  update(
+    @CurrentUser() user: AuthUser,
+    @Param('id', ParseUUIDPipe) id: string,
+    @Body() dto: UpdatePetCardDto,
+  ): Promise<PetCardResponseDto> {
+    return this.cards.update(user.userId, id, dto);
+  }
+
+  @Delete(':id')
+  @HttpCode(HttpStatus.NO_CONTENT)
+  @SkipTransform() // 204 — 본문이 없다
+  @ApiOperation({ summary: '명함 삭제' })
+  @ApiNoContentResponse({ description: '삭제 완료' })
+  @ApiErrorResponse('RES_001', '명함을 찾을 수 없음')
+  async remove(
+    @CurrentUser() user: AuthUser,
+    @Param('id', ParseUUIDPipe) id: string,
+  ): Promise<void> {
+    await this.cards.remove(user.userId, id);
+  }
+}
+
+// 아이의 대표 명함 — 아이의 하위 리소스로 둔다
+@ApiTags('PetCard')
+@ApiBearerAuth()
+@ApiErrorResponse('AUTH_001', '로그인 필요')
+@Controller('pets')
+export class RepresentativeCardController {
+  constructor(private readonly cards: PetCardService) {}
+
+  @Put(':petId/representative-card')
+  @HttpCode(HttpStatus.NO_CONTENT)
+  @SkipTransform() // 204 — 본문이 없다
+  @ApiOperation({ summary: '대표 명함 정하기' })
+  @ApiNoContentResponse({ description: '대표 명함으로 정함' })
+  @ApiErrorResponse('RES_001', '명함을 찾을 수 없음')
+  @ApiErrorResponse('VAL_001', '그 아이의 명함이 아님')
+  async set(
+    @CurrentUser() user: AuthUser,
+    @Param('petId', ParseUUIDPipe) petId: string,
+    @Body() dto: SetRepresentativeDto,
+  ): Promise<void> {
+    await this.cards.setRepresentative(user.userId, petId, dto.cardId);
+  }
+
+  @Delete(':petId/representative-card')
+  @HttpCode(HttpStatus.NO_CONTENT)
+  @SkipTransform() // 204 — 본문이 없다
+  @ApiOperation({ summary: '대표 명함 지정 풀기' })
+  @ApiNoContentResponse({ description: '지정을 풀었음' })
+  @ApiErrorResponse('RES_001', '아이를 찾을 수 없음')
+  async clear(
+    @CurrentUser() user: AuthUser,
+    @Param('petId', ParseUUIDPipe) petId: string,
+  ): Promise<void> {
+    await this.cards.clearRepresentative(user.userId, petId);
+  }
+}
diff --git a/flutter/lib/core/api/error_lexicon.g.dart b/flutter/lib/core/api/error_lexicon.g.dart
index 6cbe568..d27e14e 100644
--- a/flutter/lib/core/api/error_lexicon.g.dart
+++ b/flutter/lib/core/api/error_lexicon.g.dart
@@ -13,6 +13,7 @@ const Map<String, String> kErrorCodeMessages = {
   'FILE_002': '파일 크기가 허용 범위를 초과했습니다.',
   'DIARY_001': '다이어리는 최대 6권까지 만들 수 있어요.',
   'DIARY_002': '오늘 기록은 이미 남겼어요. 내일 다시 작성할 수 있어요.',
+  'CARD_001': '펫 명함은 최대 10장까지 만들 수 있어요.',
 };
 
 /// 매핑 실패 시 사용하는 폴백 코드
diff --git a/frontend/src/shared/constants/error-codes.generated.ts b/frontend/src/shared/constants/error-codes.generated.ts
index 9cf42b2..6fe83d5 100644
--- a/frontend/src/shared/constants/error-codes.generated.ts
+++ b/frontend/src/shared/constants/error-codes.generated.ts
@@ -13,6 +13,7 @@ export const ERROR_CODE_MESSAGES = {
   FILE_002: '파일 크기가 허용 범위를 초과했습니다.',
   DIARY_001: '다이어리는 최대 6권까지 만들 수 있어요.',
   DIARY_002: '오늘 기록은 이미 남겼어요. 내일 다시 작성할 수 있어요.',
+  CARD_001: '펫 명함은 최대 10장까지 만들 수 있어요.',
 } as const
 
 export type ErrorCode = keyof typeof ERROR_CODE_MESSAGES