diff --git a/src/app.controller.spec.ts b/src/app.controller.spec.ts
index d22f389..c46c13f 100644
--- a/src/app.controller.spec.ts
+++ b/src/app.controller.spec.ts
@@ -1,22 +1,29 @@
+import { ConflictException } from '@nestjs/common';
 import { Test, TestingModule } from '@nestjs/testing';
 import { AppController } from './app.controller';
-import { AppService } from './app.service';
+import { HiboutikService } from './services/hiboutik/hiboutik.service';
 
 describe('AppController', () => {
-  let appController: AppController;
+  let controller: AppController;
+  const hiboutikService = { startSync: jest.fn() };
 
   beforeEach(async () => {
-    const app: TestingModule = await Test.createTestingModule({
+    hiboutikService.startSync.mockReset();
+    const module: TestingModule = await Test.createTestingModule({
       controllers: [AppController],
-      providers: [AppService],
+      providers: [{ provide: HiboutikService, useValue: hiboutikService }],
     }).compile();
-
-    appController = app.get<AppController>(AppController);
+    controller = module.get(AppController);
   });
 
-  describe('root', () => {
-    it('should return "Hello World!"', () => {
-      expect(appController.getHello()).toBe('Hello World!');
-    });
+  it('starts a synchronization', () => {
+    hiboutikService.startSync.mockReturnValue(true);
+    expect(controller.hiboutikSync()).toEqual({ message: 'Hiboutik synchronization started' });
+    expect(hiboutikService.startSync).toHaveBeenCalledTimes(1);
+  });
+
+  it('rejects a synchronization when one is already running', () => {
+    hiboutikService.startSync.mockReturnValue(false);
+    expect(() => controller.hiboutikSync()).toThrow(ConflictException);
   });
 });
diff --git a/src/app.controller.ts b/src/app.controller.ts
index cce879e..345b0ed 100644
--- a/src/app.controller.ts
+++ b/src/app.controller.ts
@@ -1,12 +1,17 @@
-import { Controller, Get } from '@nestjs/common';
-import { AppService } from './app.service';
+import { ConflictException, Controller, HttpCode, HttpStatus, Post } from '@nestjs/common';
+import { HiboutikService } from './services/hiboutik/hiboutik.service';
 
 @Controller()
 export class AppController {
-  constructor(private readonly appService: AppService) {}
+  constructor(private readonly hiboutikService: HiboutikService) {}
 
-  @Get()
-  getHello(): string {
-    return this.appService.getHello();
+  /** Starts the synchronization in the background and answers immediately: 202, or 409 if one is already running. */
+  @Post('sync')
+  @HttpCode(HttpStatus.ACCEPTED)
+  hiboutikSync() {
+    if (!this.hiboutikService.startSync()) {
+      throw new ConflictException('A Hiboutik synchronization is already in progress');
+    }
+    return { message: 'Hiboutik synchronization started' };
   }
 }
diff --git a/src/app.module.ts b/src/app.module.ts
index 8662803..bb44aee 100644
--- a/src/app.module.ts
+++ b/src/app.module.ts
@@ -1,10 +1,67 @@
 import { Module } from '@nestjs/common';
 import { AppController } from './app.controller';
-import { AppService } from './app.service';
+import { ConfigModule } from '@nestjs/config';
+import { HiboutikService } from './services/hiboutik/hiboutik.service';
+import { CategoryHiboutikRepository } from './hiboutik/category.hiboutik.repository';
+import { CategoryConverter } from './models/converter/category.converter';
+import { ProductHiboutikRepository } from './hiboutik/product.hiboutik.repository';
+import { HttpModule } from '@nestjs/axios';
+import { CategoryDatabaseRepository } from './database/category.database.repository';
+import { PrismaModule } from '../prisma/prisma.module';
+import { HiboutikClient } from './hiboutik/hiboutik.client';
+import { BrandHiboutikRepository } from './hiboutik/brand.hiboutik.repository';
+import { BrandDatabaseRepository } from './database/brand.database.repository';
+import { BrandConverter } from './models/converter/brand.converter';
+import { SupplierHiboutikRepository } from './hiboutik/supplier.hiboutik.repository';
+import { SupplierDatabaseRepository } from './database/supplier.database.repository';
+import { SupplierConverter } from './models/converter/supplier.converter';
+import { StockHiboutikRepository } from './hiboutik/stock.hiboutik.repository';
+import { ProductConverter } from './models/converter/product.converter';
+import { ProductDatabaseRepository } from './database/product.database.repository';
+import { ProductVersionDatabaseRepository } from './database/productVersion.database.repository';
+import { CustomerHiboutikRepository } from './hiboutik/customer.hiboutik.repository';
+import { CustomerDatabaseRepository } from './database/customer.database.repository';
+import { CustomerConverter } from './models/converter/customer.converter';
+import { BrandHiboutikService } from './services/hiboutik/brand.hiboutik.service';
+import { CategoryHiboutikService } from './services/hiboutik/category.hiboutik.service';
+import { CustomerHiboutikService } from './services/hiboutik/customer.hiboutik.service';
+import { SupplierHiboutikService } from './services/hiboutik/supplier.hiboutik.service';
+import { ProductHiboutikService } from './services/hiboutik/product.hiboutik.service';
 
 @Module({
-  imports: [],
+  imports: [
+    ConfigModule.forRoot({
+      isGlobal: true,
+    }),
+    HttpModule.register({ timeout: 30_000 }),
+    PrismaModule,
+  ],
   controllers: [AppController],
-  providers: [AppService],
+  providers: [
+    BrandConverter,
+    BrandDatabaseRepository,
+    BrandHiboutikRepository,
+    BrandHiboutikService,
+    CategoryConverter,
+    CategoryDatabaseRepository,
+    CategoryHiboutikRepository,
+    CategoryHiboutikService,
+    CustomerHiboutikRepository,
+    CustomerDatabaseRepository,
+    CustomerConverter,
+    CustomerHiboutikService,
+    HiboutikClient,
+    HiboutikService,
+    ProductConverter,
+    ProductDatabaseRepository,
+    ProductHiboutikRepository,
+    ProductHiboutikService,
+    ProductVersionDatabaseRepository,
+    StockHiboutikRepository,
+    SupplierConverter,
+    SupplierDatabaseRepository,
+    SupplierHiboutikRepository,
+    SupplierHiboutikService,
+  ],
 })
 export class AppModule {}
diff --git a/src/app.service.ts b/src/app.service.ts
deleted file mode 100644
index 927d7cc..0000000
--- a/src/app.service.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { Injectable } from '@nestjs/common';
-
-@Injectable()
-export class AppService {
-  getHello(): string {
-    return 'Hello World!';
-  }
-}
diff --git a/src/main.ts b/src/main.ts
index f76bc8d..ff7d2ee 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -5,4 +5,4 @@ async function bootstrap() {
   const app = await NestFactory.create(AppModule);
   await app.listen(process.env.PORT ?? 3000);
 }
-bootstrap();
+void bootstrap();
diff --git a/src/services/hiboutik/brand.hiboutik.service.ts b/src/services/hiboutik/brand.hiboutik.service.ts
new file mode 100644
index 0000000..ce55ee2
--- /dev/null
+++ b/src/services/hiboutik/brand.hiboutik.service.ts
@@ -0,0 +1,38 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { BrandHiboutikRepository } from '../../hiboutik/brand.hiboutik.repository';
+import { BrandDatabaseRepository } from '../../database/brand.database.repository';
+import { BrandConverter } from '../../models/converter/brand.converter';
+import { forEachSafely } from '../../utils/sync';
+
+@Injectable()
+export class BrandHiboutikService {
+  private readonly logger = new Logger('BrandHiboutikService');
+
+  constructor(
+    private readonly brandHiboutikRepository: BrandHiboutikRepository,
+    private readonly brandDatabaseRepository: BrandDatabaseRepository,
+    private readonly brandConverter: BrandConverter,
+  ) {}
+
+  /** Mirrors Hiboutik brands: upserts each of them, then deletes the brands missing from Hiboutik. */
+  async syncBrands() {
+    const hiboutikBrands = await this.brandHiboutikRepository.getBrands();
+    // One upsert per brand: an invalid brand must not prevent the others from being saved
+    const nbFailed = await forEachSafely(
+      this.brandConverter.fromHiboutikList(hiboutikBrands),
+      (brand) => this.brandDatabaseRepository.upsert(brand),
+      this.logger,
+      (brand) => `Hiboutik brand ${brand.hiboutikId}`,
+    );
+
+    // Safety net: an empty answer from Hiboutik most likely means an API issue
+    if (hiboutikBrands.length === 0) {
+      this.logger.warn('Hiboutik returned no brands: deletion skipped.');
+      return;
+    }
+    const nbDeleted = await this.brandDatabaseRepository.deleteMissing(hiboutikBrands.map((dto) => Number(dto.brand_id)));
+    this.logger.log(
+      `Brands sync ended: ${hiboutikBrands.length - nbFailed}/${hiboutikBrands.length} synced, ${nbFailed} failed, ${nbDeleted} deleted.`,
+    );
+  }
+}
diff --git a/src/services/hiboutik/category.hiboutik.service.spec.ts b/src/services/hiboutik/category.hiboutik.service.spec.ts
new file mode 100644
index 0000000..7d1dcdb
--- /dev/null
+++ b/src/services/hiboutik/category.hiboutik.service.spec.ts
@@ -0,0 +1,89 @@
+import { Logger } from '@nestjs/common';
+import { CategoryHiboutikService } from './category.hiboutik.service';
+import { CategoryConverter } from '../../models/converter/category.converter';
+import { CategoryHiboutikDto } from '../../models/hiboutikDTO/category.hiboutik.dto';
+
+const hiboutikCategory = (id: number, parentId: number, overrides: Partial<CategoryHiboutikDto> = {}): CategoryHiboutikDto =>
+  ({
+    category_id: id,
+    category_name: `Category ${id}`,
+    category_id_parent: parentId,
+    category_enabled: 1,
+    category_enabled_www: 0,
+    category_position: 3,
+    ...overrides,
+  }) as CategoryHiboutikDto;
+
+describe('CategoryHiboutikService', () => {
+  const categoryHiboutikRepository = { getCategories: jest.fn() };
+  const categoryDatabaseRepository = { upsert: jest.fn(), setParent: jest.fn(), deleteMissing: jest.fn() };
+  let service: CategoryHiboutikService;
+  let calls: string[];
+
+  beforeAll(() => {
+    jest.spyOn(Logger.prototype, 'log').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'warn').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'error').mockImplementation(() => undefined);
+  });
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    calls = [];
+    categoryDatabaseRepository.upsert.mockImplementation((category: { hiboutikId: number }) => {
+      calls.push(`upsert ${category.hiboutikId}`);
+      return Promise.resolve({});
+    });
+    categoryDatabaseRepository.setParent.mockImplementation((id: number) => {
+      calls.push(`parent ${id}`);
+      return Promise.resolve({});
+    });
+    categoryDatabaseRepository.deleteMissing.mockResolvedValue(0);
+    service = new CategoryHiboutikService(
+      categoryHiboutikRepository as never,
+      categoryDatabaseRepository as never,
+      new CategoryConverter(),
+    );
+  });
+
+  it('stores position and web visibility', async () => {
+    categoryHiboutikRepository.getCategories.mockResolvedValue([hiboutikCategory(1, 0)]);
+
+    await service.syncCategories();
+
+    expect(categoryDatabaseRepository.upsert).toHaveBeenCalledWith({
+      hiboutikId: 1,
+      name: 'Category 1',
+      enabled: true,
+      position: 3,
+      webEnabled: false,
+    });
+  });
+
+  it('links parents once every category is saved, a child being listed before its parent', async () => {
+    categoryHiboutikRepository.getCategories.mockResolvedValue([hiboutikCategory(2, 3), hiboutikCategory(3, 0)]);
+
+    await service.syncCategories();
+
+    expect(calls).toEqual(['upsert 2', 'upsert 3', 'parent 2', 'parent 3']);
+    expect(categoryDatabaseRepository.setParent).toHaveBeenCalledWith(2, 3);
+    expect(categoryDatabaseRepository.setParent).toHaveBeenCalledWith(3, null);
+  });
+
+  it('keeps syncing the other categories when one fails, then deletes the missing ones', async () => {
+    categoryHiboutikRepository.getCategories.mockResolvedValue([hiboutikCategory(1, 0), hiboutikCategory(2, 0)]);
+    categoryDatabaseRepository.upsert.mockRejectedValueOnce(new Error('boom'));
+
+    await expect(service.syncCategories()).resolves.toBeUndefined();
+
+    expect(categoryDatabaseRepository.upsert).toHaveBeenCalledTimes(2);
+    expect(categoryDatabaseRepository.deleteMissing).toHaveBeenCalledWith([1, 2]);
+  });
+
+  it('does not delete anything when Hiboutik returns no categories', async () => {
+    categoryHiboutikRepository.getCategories.mockResolvedValue([]);
+
+    await service.syncCategories();
+
+    expect(categoryDatabaseRepository.deleteMissing).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/services/hiboutik/category.hiboutik.service.ts b/src/services/hiboutik/category.hiboutik.service.ts
new file mode 100644
index 0000000..e1454d5
--- /dev/null
+++ b/src/services/hiboutik/category.hiboutik.service.ts
@@ -0,0 +1,51 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { CategoryHiboutikRepository } from '../../hiboutik/category.hiboutik.repository';
+import { CategoryDatabaseRepository } from '../../database/category.database.repository';
+import { CategoryConverter } from '../../models/converter/category.converter';
+import { forEachSafely } from '../../utils/sync';
+
+@Injectable()
+export class CategoryHiboutikService {
+  private readonly logger = new Logger('CategoryHiboutikService');
+
+  constructor(
+    private readonly categoryHiboutikRepository: CategoryHiboutikRepository,
+    private readonly categoryDatabaseRepository: CategoryDatabaseRepository,
+    private readonly categoryConverter: CategoryConverter,
+  ) {}
+
+  /**
+   * Mirrors Hiboutik categories and their tree: upserts each of them, links them to their parent,
+   * then deletes the categories missing from Hiboutik.
+   */
+  async syncCategories() {
+    const hiboutikCategories = await this.categoryHiboutikRepository.getCategories();
+
+    // Pass 1: categories themselves. One upsert per category: an invalid category must not prevent the others from being saved
+    const nbFailed = await forEachSafely(
+      this.categoryConverter.fromHiboutikList(hiboutikCategories),
+      (category) => this.categoryDatabaseRepository.upsert(category),
+      this.logger,
+      (category) => `Hiboutik category ${category.hiboutikId}`,
+    );
+
+    // Pass 2: parent links, once every category exists (a child can come before its parent in Hiboutik's list)
+    const nbParentsFailed = await forEachSafely(
+      hiboutikCategories,
+      (dto) => this.categoryDatabaseRepository.setParent(Number(dto.category_id), Number(dto.category_id_parent) || null),
+      this.logger,
+      (dto) => `parent of Hiboutik category ${dto.category_id}`,
+    );
+
+    // Safety net: an empty answer from Hiboutik most likely means an API issue
+    if (hiboutikCategories.length === 0) {
+      this.logger.warn('Hiboutik returned no categories: deletion skipped.');
+      return;
+    }
+    const nbDeleted = await this.categoryDatabaseRepository.deleteMissing(hiboutikCategories.map((dto) => Number(dto.category_id)));
+    this.logger.log(
+      `Categories sync ended: ${hiboutikCategories.length - nbFailed}/${hiboutikCategories.length} synced, ${nbFailed} failed, ` +
+        `${nbParentsFailed} parent links failed, ${nbDeleted} deleted.`,
+    );
+  }
+}
diff --git a/src/services/hiboutik/customer.hiboutik.service.spec.ts b/src/services/hiboutik/customer.hiboutik.service.spec.ts
new file mode 100644
index 0000000..b15648a
--- /dev/null
+++ b/src/services/hiboutik/customer.hiboutik.service.spec.ts
@@ -0,0 +1,51 @@
+import { Logger } from '@nestjs/common';
+import { CustomerHiboutikService } from './customer.hiboutik.service';
+
+describe('CustomerHiboutikService', () => {
+  const customerHiboutikRepository = { getCustomers: jest.fn(), getCustomerById: jest.fn() };
+  const customerDatabaseRepository = { upsert: jest.fn(), deleteMissing: jest.fn() };
+  const customerConverter = { fromHiboutik: jest.fn() };
+  let service: CustomerHiboutikService;
+
+  beforeAll(() => {
+    jest.spyOn(Logger.prototype, 'log').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'warn').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'error').mockImplementation(() => undefined);
+  });
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    customerHiboutikRepository.getCustomers.mockResolvedValue([]);
+    customerHiboutikRepository.getCustomerById.mockResolvedValue({});
+    customerDatabaseRepository.deleteMissing.mockResolvedValue(0);
+    service = new CustomerHiboutikService(
+      customerHiboutikRepository as never,
+      customerDatabaseRepository as never,
+      customerConverter as never,
+    );
+  });
+
+  it('deletes customers missing from Hiboutik', async () => {
+    customerHiboutikRepository.getCustomers.mockResolvedValue([{ customers_id: 1 }, { customers_id: '2' }]);
+
+    await service.syncCustomers();
+
+    expect(customerDatabaseRepository.deleteMissing).toHaveBeenCalledWith([1, 2]);
+    expect(customerDatabaseRepository.upsert).toHaveBeenCalledTimes(2);
+  });
+
+  it('does not delete customers when Hiboutik returns none', async () => {
+    await service.syncCustomers();
+
+    expect(customerDatabaseRepository.deleteMissing).not.toHaveBeenCalled();
+  });
+
+  it('keeps syncing the other customers when one fails', async () => {
+    customerHiboutikRepository.getCustomers.mockResolvedValue([{ customers_id: 1 }, { customers_id: 2 }]);
+    customerHiboutikRepository.getCustomerById.mockRejectedValueOnce(new Error('boom'));
+
+    await expect(service.syncCustomers()).resolves.toBeUndefined();
+
+    expect(customerDatabaseRepository.upsert).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/services/hiboutik/customer.hiboutik.service.ts b/src/services/hiboutik/customer.hiboutik.service.ts
new file mode 100644
index 0000000..90c19a9
--- /dev/null
+++ b/src/services/hiboutik/customer.hiboutik.service.ts
@@ -0,0 +1,49 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { CustomerHiboutikRepository } from '../../hiboutik/customer.hiboutik.repository';
+import { CustomerDatabaseRepository } from '../../database/customer.database.repository';
+import { CustomerConverter } from '../../models/converter/customer.converter';
+
+@Injectable()
+export class CustomerHiboutikService {
+  private readonly logger = new Logger('CustomerHiboutikService');
+
+  constructor(
+    private readonly customerHiboutikRepository: CustomerHiboutikRepository,
+    private readonly customerDatabaseRepository: CustomerDatabaseRepository,
+    private readonly customerConverter: CustomerConverter,
+  ) {}
+
+  /**
+   * Mirrors Hiboutik customers: deletes the customers missing from Hiboutik, then fetches and upserts each of them
+   * (one API call per customer, as the list endpoint lacks addresses and sales).
+   */
+  async syncCustomers() {
+    const hiboutikCustomers = await this.customerHiboutikRepository.getCustomers();
+
+    // Safety net: an empty answer from Hiboutik most likely means an API issue
+    let nbDeleted = 0;
+    if (hiboutikCustomers.length === 0) {
+      this.logger.warn('Hiboutik returned no customers: deletion skipped.');
+    } else {
+      nbDeleted = await this.customerDatabaseRepository.deleteMissing(hiboutikCustomers.map((dto) => Number(dto.customers_id)));
+    }
+
+    let nbFailed = 0;
+    for (const hiboutikCustomer of hiboutikCustomers) {
+      try {
+        const hiboutikFullCustomer = await this.customerHiboutikRepository.getCustomerById(hiboutikCustomer.customers_id);
+        await this.customerDatabaseRepository.upsert(this.customerConverter.fromHiboutik(hiboutikFullCustomer));
+        // retreive addresses DTOs
+        // save addresses
+        // retreive orders DTOs
+        // save orders
+      } catch (error) {
+        nbFailed++;
+        this.logger.error(`Failed to sync Hiboutik customer ${hiboutikCustomer.customers_id}`, (error as Error)?.stack);
+      }
+    }
+    this.logger.log(
+      `Customers sync ended: ${hiboutikCustomers.length - nbFailed}/${hiboutikCustomers.length} synced, ${nbFailed} failed, ${nbDeleted} deleted.`,
+    );
+  }
+}
diff --git a/src/services/hiboutik/hiboutik.service.spec.ts b/src/services/hiboutik/hiboutik.service.spec.ts
new file mode 100644
index 0000000..55eed97
--- /dev/null
+++ b/src/services/hiboutik/hiboutik.service.spec.ts
@@ -0,0 +1,68 @@
+import { Logger } from '@nestjs/common';
+import { HiboutikService } from './hiboutik.service';
+
+describe('HiboutikService', () => {
+  const brandService = { syncBrands: jest.fn() };
+  const categoryService = { syncCategories: jest.fn() };
+  const supplierService = { syncSuppliers: jest.fn() };
+  const productService = { syncProducts: jest.fn() };
+  const customerService = { syncCustomers: jest.fn() };
+  let service: HiboutikService;
+
+  beforeAll(() => {
+    jest.spyOn(Logger.prototype, 'log').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'warn').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'error').mockImplementation(() => undefined);
+  });
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    brandService.syncBrands.mockResolvedValue(undefined);
+    categoryService.syncCategories.mockResolvedValue(undefined);
+    supplierService.syncSuppliers.mockResolvedValue(undefined);
+    productService.syncProducts.mockResolvedValue(undefined);
+    customerService.syncCustomers.mockResolvedValue(undefined);
+    service = new HiboutikService(
+      brandService as never,
+      categoryService as never,
+      customerService as never,
+      productService as never,
+      supplierService as never,
+    );
+  });
+
+  it('runs the steps in dependency order', async () => {
+    const order: string[] = [];
+    brandService.syncBrands.mockImplementation(() => Promise.resolve(order.push('brands')));
+    categoryService.syncCategories.mockImplementation(() => Promise.resolve(order.push('categories')));
+    supplierService.syncSuppliers.mockImplementation(() => Promise.resolve(order.push('suppliers')));
+    productService.syncProducts.mockImplementation(() => Promise.resolve(order.push('products')));
+    customerService.syncCustomers.mockImplementation(() => Promise.resolve(order.push('customers')));
+
+    await service.syncAll();
+
+    expect(order).toEqual(['brands', 'categories', 'suppliers', 'products', 'customers']);
+  });
+
+  it('continues with the next steps when one fails', async () => {
+    brandService.syncBrands.mockRejectedValue(new Error('boom'));
+
+    await service.syncAll();
+
+    expect(productService.syncProducts).toHaveBeenCalled();
+    expect(customerService.syncCustomers).toHaveBeenCalled();
+  });
+
+  it('refuses a second synchronization while one is running, and unlocks at the end', async () => {
+    let finishBrands: () => void = () => undefined;
+    brandService.syncBrands.mockReturnValue(new Promise<void>((resolve) => (finishBrands = resolve)));
+
+    expect(service.startSync()).toBe(true);
+    expect(service.isSyncInProgress).toBe(true);
+    expect(service.startSync()).toBe(false);
+
+    finishBrands();
+    await new Promise((resolve) => setImmediate(resolve));
+    expect(service.isSyncInProgress).toBe(false);
+  });
+});
diff --git a/src/services/hiboutik/hiboutik.service.ts b/src/services/hiboutik/hiboutik.service.ts
new file mode 100644
index 0000000..5578c48
--- /dev/null
+++ b/src/services/hiboutik/hiboutik.service.ts
@@ -0,0 +1,69 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { BrandHiboutikService } from './brand.hiboutik.service';
+import { CategoryHiboutikService } from './category.hiboutik.service';
+import { CustomerHiboutikService } from './customer.hiboutik.service';
+import { SupplierHiboutikService } from './supplier.hiboutik.service';
+import { ProductHiboutikService } from './product.hiboutik.service';
+
+/** Entry point of the Hiboutik → database synchronization: runs each entity sync in dependency order. */
+@Injectable()
+export class HiboutikService {
+  private readonly logger = new Logger('HiboutikService');
+  /** In-memory lock: only valid while the app runs as a single instance. */
+  private syncInProgress = false;
+
+  constructor(
+    private readonly brandHiboutikService: BrandHiboutikService,
+    private readonly categoryHiboutikService: CategoryHiboutikService,
+    private readonly customerHiboutikService: CustomerHiboutikService,
+    private readonly productHiboutikService: ProductHiboutikService,
+    private readonly supplierHiboutikService: SupplierHiboutikService,
+  ) {}
+
+  get isSyncInProgress(): boolean {
+    return this.syncInProgress;
+  }
+
+  /**
+   * Starts a full synchronization in the background.
+   * @returns false if a synchronization is already running (nothing is started).
+   */
+  startSync(): boolean {
+    if (this.syncInProgress) return false;
+
+    this.syncInProgress = true;
+    void this.syncAll()
+      .catch((error) => this.logger.error('Global Hiboutik synchronization crashed', (error as Error)?.stack))
+      .finally(() => (this.syncInProgress = false));
+    return true;
+  }
+
+  /** Runs every sync step in order. A failing step is logged and does not stop the next ones. */
+  async syncAll() {
+    this.logger.log('Starting global Hiboutik synchronization');
+    // Order matters: products connect to brands, categories and suppliers by hiboutikId.
+    const steps: [string, () => Promise<void>][] = [
+      ['brands', () => this.brandHiboutikService.syncBrands()],
+      ['categories', () => this.categoryHiboutikService.syncCategories()],
+      ['suppliers', () => this.supplierHiboutikService.syncSuppliers()],
+      ['products', () => this.productHiboutikService.syncProducts()],
+      ['customers', () => this.customerHiboutikService.syncCustomers()],
+    ];
+
+    const failedSteps: string[] = [];
+    for (const [name, step] of steps) {
+      try {
+        await step();
+      } catch (error) {
+        failedSteps.push(name);
+        this.logger.error(`Hiboutik ${name} sync failed`, (error as Error)?.stack);
+      }
+    }
+
+    if (failedSteps.length > 0) {
+      this.logger.warn(`Global Hiboutik synchronization ended with errors (failed steps: ${failedSteps.join(', ')})`);
+    } else {
+      this.logger.log('Global Hiboutik synchronization ended successfully');
+    }
+  }
+}
diff --git a/src/services/hiboutik/product.hiboutik.service.spec.ts b/src/services/hiboutik/product.hiboutik.service.spec.ts
new file mode 100644
index 0000000..ecbf373
--- /dev/null
+++ b/src/services/hiboutik/product.hiboutik.service.spec.ts
@@ -0,0 +1,162 @@
+import { Logger } from '@nestjs/common';
+import { ProductHiboutikService } from './product.hiboutik.service';
+import { ProductConverter } from '../../models/converter/product.converter';
+import { ProductHiboutikDto } from '../../models/hiboutikDTO/product.hiboutik.dto';
+import { StockHiboutikDto } from '../../models/hiboutikDTO/stock.hiboutik.dto';
+
+const hiboutikProduct = (id: number, overrides: Partial<ProductHiboutikDto> = {}): ProductHiboutikDto => ({
+  product_id: id,
+  product_model: `Product ${id}`,
+  product_barcode: `barcode-${id}`,
+  product_brand: 0,
+  product_supplier: 0,
+  product_price: '10.00',
+  product_discount_price: '0.00',
+  product_supply_price: '5.00',
+  product_category: 0,
+  product_display_www: 1,
+  product_arch: 0,
+  products_desc: '',
+  updated_at: '2026-06-28 17:02:55',
+  product_specific_rules: [],
+  ...overrides,
+});
+
+const stock = (productId: number, size: number, available: string): StockHiboutikDto => ({
+  product_id: productId,
+  product_size: size,
+  stock_available: available,
+  product_barcode: '',
+  product_supplier_reference: '',
+});
+
+describe('ProductHiboutikService', () => {
+  let service: ProductHiboutikService;
+  let calls: string[];
+  const productHiboutikRepository = { getProducts: jest.fn() };
+  const stockHiboutikRepository = { getStocks: jest.fn() };
+  const productDatabaseRepository = { getAll: jest.fn(), upsert: jest.fn(), deleteAll: jest.fn() };
+  const productVersionDatabaseRepository = { upsert: jest.fn(), deleteMissing: jest.fn() };
+
+  beforeAll(() => {
+    jest.spyOn(Logger.prototype, 'log').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'warn').mockImplementation(() => undefined);
+    jest.spyOn(Logger.prototype, 'error').mockImplementation(() => undefined);
+  });
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    calls = [];
+    stockHiboutikRepository.getStocks.mockResolvedValue([]);
+    productDatabaseRepository.getAll.mockResolvedValue([]);
+    productDatabaseRepository.deleteAll.mockImplementation((ids: string[]) => {
+      calls.push('deleteProducts');
+      return Promise.resolve(ids.length);
+    });
+    // the saved product mirrors what was upserted, like the database would
+    productDatabaseRepository.upsert.mockImplementation((product: { hiboutikId: number }) => {
+      calls.push('upsertProduct');
+      return Promise.resolve({ ...product, id: `uuid-${product.hiboutikId}` });
+    });
+    productVersionDatabaseRepository.deleteMissing.mockImplementation(() => {
+      calls.push('deleteVersions');
+      return Promise.resolve(0);
+    });
+    productVersionDatabaseRepository.upsert.mockImplementation(() => {
+      calls.push('upsertVersion');
+      return Promise.resolve({});
+    });
+
+    service = new ProductHiboutikService(
+      productHiboutikRepository as never,
+      productDatabaseRepository as never,
+      productVersionDatabaseRepository as never,
+      new ProductConverter(),
+      stockHiboutikRepository as never,
+    );
+  });
+
+  it('deletes products missing from Hiboutik, before upserting', async () => {
+    productHiboutikRepository.getProducts.mockResolvedValue([hiboutikProduct(1)]);
+    productDatabaseRepository.getAll.mockResolvedValue([
+      { id: 'uuid-1', hiboutikId: 1 },
+      { id: 'uuid-2', hiboutikId: 2 },
+    ]);
+
+    await service.syncProducts();
+
+    expect(productDatabaseRepository.deleteAll).toHaveBeenCalledWith(['uuid-2']);
+    expect(calls[0]).toBe('deleteProducts');
+  });
+
+  it('does not delete anything when Hiboutik returns no products', async () => {
+    productHiboutikRepository.getProducts.mockResolvedValue([]);
+    productDatabaseRepository.getAll.mockResolvedValue([{ id: 'uuid-1', hiboutikId: 1 }]);
+
+    await service.syncProducts();
+
+    expect(productDatabaseRepository.deleteAll).not.toHaveBeenCalled();
+  });
+
+  it('creates a single version for a product without sizes', async () => {
+    productHiboutikRepository.getProducts.mockResolvedValue([hiboutikProduct(1)]);
+    stockHiboutikRepository.getStocks.mockResolvedValue([stock(1, 0, '4'), stock(2, 0, '99')]);
+
+    await service.syncProducts();
+
+    expect(productDatabaseRepository.upsert).toHaveBeenCalledWith(expect.objectContaining({ hiboutikId: 1, globalStock: 4 }));
+    expect(productVersionDatabaseRepository.deleteMissing).toHaveBeenCalledWith('uuid-1', [0]);
+    expect(productVersionDatabaseRepository.upsert).toHaveBeenCalledTimes(1);
+    expect(productVersionDatabaseRepository.upsert).toHaveBeenCalledWith(
+      'uuid-1',
+      expect.objectContaining({ hiboutikSizeId: 0, barcode: 'barcode-1', stock: 4, versionName: 'Product 1', discountPrice: null }),
+    );
+  });
+
+  it('creates one version per size, with specific rules and stocks, after deleting removed sizes', async () => {
+    productHiboutikRepository.getProducts.mockResolvedValue([
+      hiboutikProduct(1, {
+        product_size_details: [
+          { size_id: 10, size_name: 'S', barcode: 'b-s' },
+          { size_id: 11, size_name: 'M', barcode: '' },
+        ],
+        product_specific_rules: [{ size_id: 10, barcode: 'b-s', product_price: '12.00', product_discount_price: '0.00' }],
+      }),
+    ]);
+    stockHiboutikRepository.getStocks.mockResolvedValue([stock(1, 10, '3'), stock(1, 11, '2')]);
+
+    await service.syncProducts();
+
+    expect(productDatabaseRepository.upsert).toHaveBeenCalledWith(expect.objectContaining({ globalStock: 5 }));
+    expect(productVersionDatabaseRepository.deleteMissing).toHaveBeenCalledWith('uuid-1', [10, 11]);
+    expect(calls).toEqual(['deleteProducts', 'upsertProduct', 'deleteVersions', 'upsertVersion', 'upsertVersion']);
+    expect(productVersionDatabaseRepository.upsert).toHaveBeenNthCalledWith(1, 'uuid-1', {
+      barcode: 'b-s',
+      discountPrice: null,
+      hiboutikSizeId: 10,
+      price: '12.00',
+      product: { connect: { id: 'uuid-1' } },
+      stock: 3,
+      versionName: 'S',
+    });
+    expect(productVersionDatabaseRepository.upsert).toHaveBeenNthCalledWith(2, 'uuid-1', {
+      barcode: null,
+      discountPrice: null,
+      hiboutikSizeId: 11,
+      price: null,
+      product: { connect: { id: 'uuid-1' } },
+      stock: 2,
+      versionName: 'M',
+    });
+  });
+
+  it('keeps syncing the other products when one fails', async () => {
+    productHiboutikRepository.getProducts.mockResolvedValue([hiboutikProduct(1), hiboutikProduct(2)]);
+    productDatabaseRepository.upsert.mockRejectedValueOnce(new Error('boom'));
+
+    await expect(service.syncProducts()).resolves.toBeUndefined();
+
+    expect(productDatabaseRepository.upsert).toHaveBeenCalledTimes(2);
+    expect(productVersionDatabaseRepository.upsert).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/services/hiboutik/product.hiboutik.service.ts b/src/services/hiboutik/product.hiboutik.service.ts
new file mode 100644
index 0000000..2a64ca2
--- /dev/null
+++ b/src/services/hiboutik/product.hiboutik.service.ts
@@ -0,0 +1,131 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { ProductHiboutikRepository } from '../../hiboutik/product.hiboutik.repository';
+import { ProductDatabaseRepository } from '../../database/product.database.repository';
+import { ProductVersionDatabaseRepository } from '../../database/productVersion.database.repository';
+import { ProductConverter } from '../../models/converter/product.converter';
+import { StockHiboutikRepository } from '../../hiboutik/stock.hiboutik.repository';
+import { ProductHiboutikDto } from '../../models/hiboutikDTO/product.hiboutik.dto';
+import { StockHiboutikDto } from '../../models/hiboutikDTO/stock.hiboutik.dto';
+import { Product } from '../../../prisma/generated/client';
+import { ProductVersionCreateInput } from '../../../prisma/generated/models/ProductVersion';
+import { parseOptionalHiboutikPrice } from '../../utils/price';
+
+/** Version id used for products that have no sizes in Hiboutik. */
+const NO_SIZE_ID = 0;
+
+@Injectable()
+export class ProductHiboutikService {
+  private readonly logger = new Logger('ProductHiboutikService');
+
+  constructor(
+    private readonly productHiboutikRepository: ProductHiboutikRepository,
+    private readonly productDatabaseRepository: ProductDatabaseRepository,
+    private readonly productVersionDatabaseRepository: ProductVersionDatabaseRepository,
+    private readonly productConverter: ProductConverter,
+    private readonly stockHiboutikRepository: StockHiboutikRepository,
+  ) {}
+
+  /** Mirrors Hiboutik products, their versions (sizes) and stocks. Products missing from Hiboutik are deleted. */
+  async syncProducts() {
+    this.logger.log('Starting products sync');
+    const [productsHiboutik, hiboutikStocks, existingProducts] = await Promise.all([
+      this.productHiboutikRepository.getProducts(),
+      this.stockHiboutikRepository.getStocks(),
+      this.productDatabaseRepository.getAll(),
+    ]);
+
+    // Deletion happens before upserts so that a product recreated in Hiboutik (new id, same barcode)
+    // does not collide with the old one on the unique barcode.
+    const nbDeleted = await this.deleteMissingProducts(productsHiboutik, existingProducts);
+
+    let nbFailed = 0;
+    for (const productHiboutik of productsHiboutik) {
+      const hiboutikProductStocks = hiboutikStocks.filter((stock) => stock.product_id === Number(productHiboutik.product_id));
+      try {
+        await this.updateProduct(productHiboutik, hiboutikProductStocks);
+      } catch (error) {
+        nbFailed++;
+        this.logger.error(`Failed to sync Hiboutik product ${productHiboutik.product_id}`, (error as Error)?.stack);
+      }
+    }
+
+    this.logger.log(
+      `Products sync ended: ${productsHiboutik.length - nbFailed}/${productsHiboutik.length} synced, ${nbFailed} failed, ${nbDeleted} deleted.`,
+    );
+  }
+
+  /** @returns the number of deleted products. */
+  private async deleteMissingProducts(productsHiboutik: ProductHiboutikDto[], existingProducts: Product[]): Promise<number> {
+    // Safety net: an empty answer from Hiboutik most likely means an API issue, not an empty catalog
+    if (productsHiboutik.length === 0 && existingProducts.length > 0) {
+      this.logger.warn(`Hiboutik returned no products while ${existingProducts.length} exist in database: deletion skipped.`);
+      return 0;
+    }
+
+    const hiboutikIds = new Set(productsHiboutik.map((product) => Number(product.product_id)));
+    const missingProductIds = existingProducts.filter((product) => !hiboutikIds.has(product.hiboutikId)).map((product) => product.id);
+    return this.productDatabaseRepository.deleteAll(missingProductIds);
+  }
+
+  /** Upserts a product with its global stock, then replaces its versions. */
+  private async updateProduct(productHiboutik: ProductHiboutikDto, productStocks: StockHiboutikDto[]): Promise<void> {
+    const newProduct = this.productConverter.fromHiboutik(productHiboutik);
+    newProduct.globalStock = productStocks.map((stock) => Number(stock.stock_available)).reduce((sum, stock) => sum + stock, 0);
+
+    const savedProduct: Product = await this.productDatabaseRepository.upsert(newProduct);
+    const versions = this.buildVersions(productHiboutik, productStocks, savedProduct);
+
+    // Same reason as for products: delete removed versions first to free their barcodes
+    await this.productVersionDatabaseRepository.deleteMissing(
+      savedProduct.id,
+      versions.map((version) => version.hiboutikSizeId),
+    );
+    for (const version of versions) {
+      await this.productVersionDatabaseRepository.upsert(savedProduct.id, version);
+    }
+  }
+
+  /**
+   * Builds the versions of a product: one per Hiboutik size, or a single {@link NO_SIZE_ID} version
+   * copying the product's barcode, prices and stock when it has no sizes.
+   */
+  private buildVersions(
+    productHiboutik: ProductHiboutikDto,
+    productStocks: StockHiboutikDto[],
+    savedProduct: Product,
+  ): ProductVersionCreateInput[] {
+    const specificRules = productHiboutik.product_specific_rules ?? [];
+    const sizesDetails = productHiboutik.product_size_details ?? [];
+
+    if (sizesDetails.length === 0) {
+      return [
+        {
+          barcode: savedProduct.barcode,
+          discountPrice: savedProduct.discountPrice,
+          hiboutikSizeId: NO_SIZE_ID,
+          price: savedProduct.price,
+          product: { connect: { id: savedProduct.id } },
+          stock: savedProduct.globalStock,
+          versionName: savedProduct.name,
+        },
+      ];
+    }
+
+    return sizesDetails.map((sizeDetails) => {
+      const sizeId = Number(sizeDetails.size_id);
+      const specificRule = specificRules.find((rule) => Number(rule.size_id) === sizeId);
+      const stock = productStocks.find((stock) => stock.product_size === sizeId);
+      // Values are always set explicitly (null / 0 rather than undefined), otherwise Prisma would keep
+      // the previous value on update when a rule or a stock is removed in Hiboutik.
+      return {
+        barcode: sizeDetails.barcode || null,
+        discountPrice: parseOptionalHiboutikPrice(specificRule?.product_discount_price),
+        hiboutikSizeId: sizeId,
+        price: parseOptionalHiboutikPrice(specificRule?.product_price),
+        product: { connect: { id: savedProduct.id } },
+        stock: stock ? Number(stock.stock_available) : 0,
+        versionName: sizeDetails.size_name,
+      };
+    });
+  }
+}
diff --git a/src/services/hiboutik/supplier.hiboutik.service.ts b/src/services/hiboutik/supplier.hiboutik.service.ts
new file mode 100644
index 0000000..5a5673b
--- /dev/null
+++ b/src/services/hiboutik/supplier.hiboutik.service.ts
@@ -0,0 +1,38 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { SupplierHiboutikRepository } from '../../hiboutik/supplier.hiboutik.repository';
+import { SupplierDatabaseRepository } from '../../database/supplier.database.repository';
+import { SupplierConverter } from '../../models/converter/supplier.converter';
+import { forEachSafely } from '../../utils/sync';
+
+@Injectable()
+export class SupplierHiboutikService {
+  private readonly logger = new Logger('SupplierHiboutikService');
+
+  constructor(
+    private readonly supplierHiboutikRepository: SupplierHiboutikRepository,
+    private readonly supplierDatabaseRepository: SupplierDatabaseRepository,
+    private readonly supplierConverter: SupplierConverter,
+  ) {}
+
+  /** Mirrors Hiboutik suppliers: upserts each of them, then deletes the suppliers missing from Hiboutik. */
+  async syncSuppliers() {
+    const hiboutikSuppliers = await this.supplierHiboutikRepository.getSuppliers();
+    // One upsert per supplier: an invalid supplier must not prevent the others from being saved
+    const nbFailed = await forEachSafely(
+      this.supplierConverter.fromHiboutikList(hiboutikSuppliers),
+      (supplier) => this.supplierDatabaseRepository.upsert(supplier),
+      this.logger,
+      (supplier) => `Hiboutik supplier ${supplier.hiboutikId}`,
+    );
+
+    // Safety net: an empty answer from Hiboutik most likely means an API issue
+    if (hiboutikSuppliers.length === 0) {
+      this.logger.warn('Hiboutik returned no suppliers: deletion skipped.');
+      return;
+    }
+    const nbDeleted = await this.supplierDatabaseRepository.deleteMissing(hiboutikSuppliers.map((dto) => Number(dto.supplier_id)));
+    this.logger.log(
+      `Suppliers sync ended: ${hiboutikSuppliers.length - nbFailed}/${hiboutikSuppliers.length} synced, ${nbFailed} failed, ${nbDeleted} deleted.`,
+    );
+  }
+}
diff --git a/src/utils/sync.ts b/src/utils/sync.ts
new file mode 100644
index 0000000..4477887
--- /dev/null
+++ b/src/utils/sync.ts
@@ -0,0 +1,24 @@
+import { Logger } from '@nestjs/common';
+
+/**
+ * Runs `action` on each item, one at a time: a failing item is logged and skipped, the others are still processed.
+ * @param describe label of an item in the error log, e.g. "Hiboutik brand 12".
+ * @returns the number of failed items.
+ */
+export async function forEachSafely<T>(
+  items: T[],
+  action: (item: T) => Promise<unknown>,
+  logger: Logger,
+  describe: (item: T) => string,
+): Promise<number> {
+  let nbFailed = 0;
+  for (const item of items) {
+    try {
+      await action(item);
+    } catch (error) {
+      nbFailed++;
+      logger.error(`Failed to sync ${describe(item)}`, (error as Error)?.stack);
+    }
+  }
+  return nbFailed;
+}
diff --git a/test/app.e2e-spec.ts b/test/app.e2e-spec.ts
index a767839..07f5664 100644
--- a/test/app.e2e-spec.ts
+++ b/test/app.e2e-spec.ts
@@ -3,24 +3,37 @@ import { INestApplication } from '@nestjs/common';
 import request from 'supertest';
 import { App } from 'supertest/types';
 import { AppModule } from './../src/app.module';
+import { HiboutikService } from './../src/services/hiboutik/hiboutik.service';
+import { PrismaService } from './../prisma/prisma.service';
 
+// Boots the real AppModule wiring, without database nor Hiboutik calls
 describe('AppController (e2e)', () => {
   let app: INestApplication<App>;
+  const hiboutikService = { startSync: jest.fn() };
 
   beforeEach(async () => {
+    hiboutikService.startSync.mockReset();
     const moduleFixture: TestingModule = await Test.createTestingModule({
       imports: [AppModule],
-    }).compile();
+    })
+      .overrideProvider(PrismaService)
+      .useValue({})
+      .overrideProvider(HiboutikService)
+      .useValue(hiboutikService)
+      .compile();
 
     app = moduleFixture.createNestApplication();
     await app.init();
   });
 
-  it('/ (GET)', () => {
-    return request(app.getHttpServer())
-      .get('/')
-      .expect(200)
-      .expect('Hello World!');
+  it('POST /sync starts a synchronization (202)', () => {
+    hiboutikService.startSync.mockReturnValue(true);
+    return request(app.getHttpServer()).post('/sync').expect(202).expect({ message: 'Hiboutik synchronization started' });
+  });
+
+  it('POST /sync answers 409 when a synchronization is already running', () => {
+    hiboutikService.startSync.mockReturnValue(false);
+    return request(app.getHttpServer()).post('/sync').expect(409);
   });
 
   afterEach(async () => {