diff --git a/ApiCore-Backend/src/app.module.ts b/ApiCore-Backend/src/app.module.ts
index 8a2944d..2aee6be 100644
--- a/ApiCore-Backend/src/app.module.ts
+++ b/ApiCore-Backend/src/app.module.ts
@@ -17,6 +17,7 @@ import { FeedingsModule } from './feedings/feedings.module';
 import { HarvestsModule } from './harvests/harvests.module';
 import { ExtractionsModule } from './extractions/extractions.module';
 import { HoneyBatchesModule } from './honey-batches/honey-batches.module';
+import { StorageModule } from './storage/storage.module';
 import { JwtAuthGuard } from './auth/guards/jwt-auth.guard';
 import { RolesGuard } from './auth/guards/roles.guard';
 
@@ -39,6 +40,7 @@ import { RolesGuard } from './auth/guards/roles.guard';
     HarvestsModule,
     ExtractionsModule,
     HoneyBatchesModule,
+    StorageModule,
   ],
   controllers: [],
   providers: [
diff --git a/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts b/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts
new file mode 100644
index 0000000..f64f1ed
--- /dev/null
+++ b/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts
@@ -0,0 +1,32 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsEnum, IsNumber, IsOptional, IsString } from 'class-validator';
+import { StockCategory } from '../../../generated/prisma';
+
+export class CreateStockItemDto {
+  @ApiProperty()
+  @IsString()
+  name!: string;
+
+  @ApiProperty({ enum: StockCategory })
+  @IsEnum(StockCategory)
+  category!: StockCategory;
+
+  @ApiProperty()
+  @IsString()
+  unit!: string;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsNumber()
+  quantity?: number;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsNumber()
+  minThreshold?: number;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  notes?: string;
+}
diff --git a/ApiCore-Backend/src/storage/dto/create-stock-movement.dto.ts b/ApiCore-Backend/src/storage/dto/create-stock-movement.dto.ts
new file mode 100644
index 0000000..3974133
--- /dev/null
+++ b/ApiCore-Backend/src/storage/dto/create-stock-movement.dto.ts
@@ -0,0 +1,28 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsEnum, IsNumber, IsOptional, IsString } from 'class-validator';
+import { StockMovementType } from '../../../generated/prisma';
+
+export class CreateStockMovementDto {
+  @ApiProperty({ enum: StockMovementType })
+  @IsEnum(StockMovementType)
+  type!: StockMovementType;
+
+  @ApiProperty()
+  @IsNumber()
+  quantity!: number;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  relatedType?: string;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  relatedId?: string;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  notes?: string;
+}
diff --git a/ApiCore-Backend/src/storage/dto/create-storage-container.dto.ts b/ApiCore-Backend/src/storage/dto/create-storage-container.dto.ts
new file mode 100644
index 0000000..c6259e8
--- /dev/null
+++ b/ApiCore-Backend/src/storage/dto/create-storage-container.dto.ts
@@ -0,0 +1,23 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsNumber, IsOptional, IsString } from 'class-validator';
+
+export class CreateStorageContainerDto {
+  @ApiProperty()
+  @IsString()
+  code!: string;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  containerType?: string;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsNumber()
+  capacity?: number;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  location?: string;
+}
diff --git a/ApiCore-Backend/src/storage/storage.controller.ts b/ApiCore-Backend/src/storage/storage.controller.ts
new file mode 100644
index 0000000..5a2c849
--- /dev/null
+++ b/ApiCore-Backend/src/storage/storage.controller.ts
@@ -0,0 +1,60 @@
+import { Body, Controller, Get, Param, Post } from '@nestjs/common';
+import { ApiBearerAuth, ApiTags } from '@nestjs/swagger';
+import { Role } from '../../generated/prisma';
+import { Roles } from '../auth/decorators/roles.decorator';
+import { CurrentUser } from '../auth/decorators/current-user.decorator';
+import type { AuthenticatedUser } from '../auth/types/authenticated-user';
+import { CreateStorageContainerDto } from './dto/create-storage-container.dto';
+import { CreateStockItemDto } from './dto/create-stock-item.dto';
+import { CreateStockMovementDto } from './dto/create-stock-movement.dto';
+import { StorageService } from './storage.service';
+
+@ApiTags('storage')
+@ApiBearerAuth()
+@Controller()
+export class StorageController {
+  constructor(private readonly storageService: StorageService) {}
+
+  @Get('storage-containers')
+  findAllContainers() {
+    return this.storageService.findAllContainers();
+  }
+
+  @Roles(Role.ADMIN, Role.BEEKEEPER)
+  @Post('storage-containers')
+  createContainer(
+    @Body() dto: CreateStorageContainerDto,
+    @CurrentUser() actor: AuthenticatedUser,
+  ) {
+    return this.storageService.createContainer(dto, actor.id);
+  }
+
+  @Get('stock-items')
+  findAllStockItems() {
+    return this.storageService.findAllStockItems();
+  }
+
+  @Get('stock-items/:id')
+  findStockItem(@Param('id') id: string) {
+    return this.storageService.findStockItemById(id);
+  }
+
+  @Roles(Role.ADMIN, Role.BEEKEEPER)
+  @Post('stock-items')
+  createStockItem(
+    @Body() dto: CreateStockItemDto,
+    @CurrentUser() actor: AuthenticatedUser,
+  ) {
+    return this.storageService.createStockItem(dto, actor.id);
+  }
+
+  @Roles(Role.ADMIN, Role.BEEKEEPER)
+  @Post('stock-items/:id/movements')
+  addMovement(
+    @Param('id') id: string,
+    @Body() dto: CreateStockMovementDto,
+    @CurrentUser() actor: AuthenticatedUser,
+  ) {
+    return this.storageService.addMovement(id, dto, actor.id);
+  }
+}
diff --git a/ApiCore-Backend/src/storage/storage.module.ts b/ApiCore-Backend/src/storage/storage.module.ts
new file mode 100644
index 0000000..2ba2abd
--- /dev/null
+++ b/ApiCore-Backend/src/storage/storage.module.ts
@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { StorageController } from './storage.controller';
+import { StorageService } from './storage.service';
+
+@Module({
+  controllers: [StorageController],
+  providers: [StorageService],
+  exports: [StorageService],
+})
+export class StorageModule {}
diff --git a/ApiCore-Backend/src/storage/storage.service.spec.ts b/ApiCore-Backend/src/storage/storage.service.spec.ts
new file mode 100644
index 0000000..cb93a02
--- /dev/null
+++ b/ApiCore-Backend/src/storage/storage.service.spec.ts
@@ -0,0 +1,95 @@
+import { NotFoundException } from '@nestjs/common';
+import { StorageService } from './storage.service';
+import { PrismaService } from '../prisma/prisma.service';
+import { AuditLogService } from '../audit/audit-log.service';
+
+describe('StorageService', () => {
+  let service: StorageService;
+  let prisma: {
+    storageContainer: { findMany: jest.Mock; create: jest.Mock };
+    stockItem: {
+      findMany: jest.Mock;
+      findUnique: jest.Mock;
+      create: jest.Mock;
+    };
+    $transaction: jest.Mock;
+  };
+  let auditLog: { record: jest.Mock };
+  let tx: {
+    stockMovement: { create: jest.Mock };
+    stockItem: { update: jest.Mock };
+  };
+
+  const stockItem = { id: 'item-1', name: 'Zuckerlösung', quantity: 10 };
+  const movement = {
+    id: 'movement-1',
+    stockItemId: 'item-1',
+    type: 'IN',
+    quantity: 5,
+  };
+
+  beforeEach(() => {
+    tx = {
+      stockMovement: { create: jest.fn().mockResolvedValue(movement) },
+      stockItem: { update: jest.fn() },
+    };
+    prisma = {
+      storageContainer: { findMany: jest.fn(), create: jest.fn() },
+      stockItem: {
+        findMany: jest.fn(),
+        findUnique: jest.fn(),
+        create: jest.fn(),
+      },
+      $transaction: jest.fn((callback: (txArg: typeof tx) => unknown) =>
+        callback(tx),
+      ),
+    };
+    auditLog = { record: jest.fn() };
+    service = new StorageService(
+      prisma as unknown as PrismaService,
+      auditLog as unknown as AuditLogService,
+    );
+  });
+
+  it('findStockItemById throws NotFoundException when missing', async () => {
+    prisma.stockItem.findUnique.mockResolvedValue(null);
+    await expect(service.findStockItemById('missing')).rejects.toBeInstanceOf(
+      NotFoundException,
+    );
+  });
+
+  it('addMovement increments quantity for an IN movement', async () => {
+    prisma.stockItem.findUnique.mockResolvedValue(stockItem);
+
+    await service.addMovement('item-1', { type: 'IN', quantity: 5 }, 'user-1');
+
+    const [[updateArg]] = tx.stockItem.update.mock.calls as [
+      [{ where: { id: string }; data: { quantity: { increment: number } } }],
+    ];
+    expect(updateArg.where.id).toBe('item-1');
+    expect(updateArg.data.quantity.increment).toBe(5);
+  });
+
+  it('addMovement decrements quantity for an OUT movement', async () => {
+    prisma.stockItem.findUnique.mockResolvedValue(stockItem);
+
+    await service.addMovement('item-1', { type: 'OUT', quantity: 3 }, 'user-1');
+
+    const [[updateArg]] = tx.stockItem.update.mock.calls as [
+      [{ data: { quantity: { increment: number } } }],
+    ];
+    expect(updateArg.data.quantity.increment).toBe(-3);
+  });
+
+  it('addMovement leaves quantity untouched for a TRANSFER movement', async () => {
+    prisma.stockItem.findUnique.mockResolvedValue(stockItem);
+
+    await service.addMovement(
+      'item-1',
+      { type: 'TRANSFER', quantity: 3 },
+      'user-1',
+    );
+
+    expect(tx.stockItem.update).not.toHaveBeenCalled();
+  });
+});
diff --git a/ApiCore-Backend/src/storage/storage.service.ts b/ApiCore-Backend/src/storage/storage.service.ts
new file mode 100644
index 0000000..4a625e4
--- /dev/null
+++ b/ApiCore-Backend/src/storage/storage.service.ts
@@ -0,0 +1,101 @@
+import { Injectable, NotFoundException } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+import { AuditLogService } from '../audit/audit-log.service';
+import { StockItem, StorageContainer } from '../../generated/prisma';
+import { CreateStorageContainerDto } from './dto/create-storage-container.dto';
+import { CreateStockItemDto } from './dto/create-stock-item.dto';
+import { CreateStockMovementDto } from './dto/create-stock-movement.dto';
+
+@Injectable()
+export class StorageService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly auditLog: AuditLogService,
+  ) {}
+
+  async findAllContainers(): Promise<StorageContainer[]> {
+    return this.prisma.storageContainer.findMany({ orderBy: { code: 'asc' } });
+  }
+
+  async createContainer(
+    dto: CreateStorageContainerDto,
+    actingUserId: string,
+  ): Promise<StorageContainer> {
+    const container = await this.prisma.storageContainer.create({
+      data: { ...dto },
+    });
+    await this.auditLog.record({
+      entityType: 'StorageContainer',
+      entityId: container.id,
+      action: 'CREATE',
+      userId: actingUserId,
+      afterData: container,
+    });
+    return container;
+  }
+
+  async findAllStockItems(): Promise<StockItem[]> {
+    return this.prisma.stockItem.findMany({ orderBy: { name: 'asc' } });
+  }
+
+  async findStockItemById(id: string) {
+    const stockItem = await this.prisma.stockItem.findUnique({
+      where: { id },
+      include: { movements: { orderBy: { date: 'desc' } } },
+    });
+    if (!stockItem) {
+      throw new NotFoundException('Stock item not found');
+    }
+    return stockItem;
+  }
+
+  async createStockItem(
+    dto: CreateStockItemDto,
+    actingUserId: string,
+  ): Promise<StockItem> {
+    const stockItem = await this.prisma.stockItem.create({ data: { ...dto } });
+    await this.auditLog.record({
+      entityType: 'StockItem',
+      entityId: stockItem.id,
+      action: 'CREATE',
+      userId: actingUserId,
+      afterData: stockItem,
+    });
+    return stockItem;
+  }
+
+  async addMovement(
+    id: string,
+    dto: CreateStockMovementDto,
+    actingUserId: string,
+  ) {
+    await this.findStockItemById(id);
+    const delta =
+      dto.type === 'IN' || dto.type === 'ADJUSTMENT'
+        ? dto.quantity
+        : dto.type === 'OUT'
+          ? -dto.quantity
+          : 0;
+
+    const movement = await this.prisma.$transaction(async (tx) => {
+      const created = await tx.stockMovement.create({
+        data: { ...dto, stockItemId: id, userId: actingUserId },
+      });
+      if (delta !== 0) {
+        await tx.stockItem.update({
+          where: { id },
+          data: { quantity: { increment: delta } },
+        });
+      }
+      return created;
+    });
+    await this.auditLog.record({
+      entityType: 'StockMovement',
+      entityId: movement.id,
+      action: 'CREATE',
+      userId: actingUserId,
+      afterData: movement,
+    });
+    return this.findStockItemById(id);
+  }
+}
diff --git a/ApiCore-Backend/test/storage.e2e-spec.ts b/ApiCore-Backend/test/storage.e2e-spec.ts
new file mode 100644
index 0000000..bee00d3
--- /dev/null
+++ b/ApiCore-Backend/test/storage.e2e-spec.ts
@@ -0,0 +1,108 @@
+import { INestApplication } from '@nestjs/common';
+import * as bcrypt from 'bcryptjs';
+import request from 'supertest';
+import { App } from 'supertest/types';
+import { PrismaService } from '../src/prisma/prisma.service';
+import { createTestApp } from './utils/create-test-app';
+import { login } from './utils/api';
+
+interface StockItemBody {
+  id: string;
+  quantity: number;
+}
+
+describe('Storage (e2e)', () => {
+  let app: INestApplication<App>;
+  let prisma: PrismaService;
+  const beekeeperEmail = `storage-e2e-beekeeper-${Date.now()}@example.com`;
+  const staffEmail = `storage-e2e-staff-${Date.now()}@example.com`;
+  const password = 'SuperSecret123!';
+  let beekeeperId: string;
+  let staffId: string;
+  let beekeeperToken: string;
+  let staffToken: string;
+  let stockItemId: string;
+
+  beforeAll(async () => {
+    app = await createTestApp();
+    prisma = app.get(PrismaService);
+
+    const passwordHash = await bcrypt.hash(password, 12);
+    const beekeeper = await prisma.user.create({
+      data: {
+        email: beekeeperEmail,
+        passwordHash,
+        name: 'Beekeeper',
+        role: 'BEEKEEPER',
+      },
+    });
+    beekeeperId = beekeeper.id;
+    const staff = await prisma.user.create({
+      data: { email: staffEmail, passwordHash, name: 'Staff', role: 'STAFF' },
+    });
+    staffId = staff.id;
+    beekeeperToken = (await login(app, beekeeperEmail, password)).accessToken;
+    staffToken = (await login(app, staffEmail, password)).accessToken;
+  });
+
+  afterAll(async () => {
+    if (stockItemId) {
+      await prisma.stockMovement.deleteMany({ where: { stockItemId } });
+      await prisma.stockItem.deleteMany({ where: { id: stockItemId } });
+    }
+    await prisma.refreshToken.deleteMany({
+      where: { userId: { in: [beekeeperId, staffId] } },
+    });
+    await prisma.auditLog.deleteMany({
+      where: { userId: { in: [beekeeperId, staffId] } },
+    });
+    await prisma.user.deleteMany({
+      where: { id: { in: [beekeeperId, staffId] } },
+    });
+    await app.close();
+  });
+
+  it('rejects create for a STAFF user', () => {
+    return request(app.getHttpServer())
+      .post('/api/v1/stock-items')
+      .set('Authorization', `Bearer ${staffToken}`)
+      .send({ name: 'Zuckerlösung', category: 'CONSUMABLE', unit: 'l' })
+      .expect(403);
+  });
+
+  it('lets a BEEKEEPER user create a stock item', async () => {
+    const response = await request(app.getHttpServer())
+      .post('/api/v1/stock-items')
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .send({
+        name: 'Zuckerlösung',
+        category: 'CONSUMABLE',
+        unit: 'l',
+        quantity: 10,
+      })
+      .expect(201);
+    const stockItem = response.body as StockItemBody;
+    stockItemId = stockItem.id;
+    expect(stockItem.quantity).toBe(10);
+  });
+
+  it('increments quantity on an IN movement', async () => {
+    const response = await request(app.getHttpServer())
+      .post(`/api/v1/stock-items/${stockItemId}/movements`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .send({ type: 'IN', quantity: 5 })
+      .expect(201);
+    const stockItem = response.body as StockItemBody;
+    expect(stockItem.quantity).toBe(15);
+  });
+
+  it('decrements quantity on an OUT movement', async () => {
+    const response = await request(app.getHttpServer())
+      .post(`/api/v1/stock-items/${stockItemId}/movements`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .send({ type: 'OUT', quantity: 4 })
+      .expect(201);
+    const stockItem = response.body as StockItemBody;
+    expect(stockItem.quantity).toBe(11);
+  });
+});
diff --git a/TASKS.md b/TASKS.md
index 4054618..b1744e8 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -106,7 +106,7 @@ Abgeleitet aus [`docs/lastenheft.md`](docs/lastenheft.md) Abschnitt 26. Reihenfo
 - Backend: `StorageModule` (StorageContainer, StockItem, StockMovement)
 - Endpunkte: `GET/POST /api/v1/storage-containers`, `GET/POST /api/v1/stock-items`, `POST /api/v1/stock-items/:id/movements`
 - Frontend: `/storage`
-- [ ] Backend-Modul fertig, getestet, grün, committet
+- [x] Backend-Modul fertig, getestet, grün, committet
 - [ ] Frontend-Views fertig, getestet, grün, committet
 
 ### 13. Dashboard