# Architecture Document
Generated: Tuesday, September 16, 2025

## System Overview
The Angular Clarity Boilerplate is a frontend-only, single-page application (SPA) template. It is designed to serve as a foundational starting point for developing enterprise-grade web applications. The system provides a pre-configured, modular, and scalable architecture using the Angular framework and is visually styled with the VMware Clarity Design System. Its primary purpose is to accelerate development by providing a structured and feature-rich starting point.

## Architecture Pattern
The boilerplate is built upon a **Component-Based Architecture**, which is fundamental to the Angular framework. The UI is composed of a tree of reusable and encapsulated components.

The overall architectural pattern follows best practices for scalable Angular applications, emphasizing a **Modular Design**. The application is segregated into a `CoreModule`, a `SharedModule`, and is designed for the addition of multiple `FeatureModules`. This structure promotes separation of concerns, reusability, and maintainability.

## Component Design (Frontend)

- **AppModule:** The root module of the application, responsible for bootstrapping the `AppComponent` and importing essential modules like the `CoreModule` and `AppRoutingModule`.

- **AppComponent:** The main application shell component. It contains the primary layout, including the Clarity header, sidebar navigation, and the main content area where routed components are displayed via `<router-outlet>`.

- **CoreModule:** This module is designed to be imported only once by the `AppModule`. It contains singleton services, route guards, and other one-time setup logic (e.g., HTTP interceptors). This pattern prevents services from being provided multiple times across the application.

- **SharedModule:** This module contains commonly used components, directives, and pipes that can be reused across different feature modules. It is imported by feature modules whenever they need access to these shared elements. It primarily exports common Angular modules (like `CommonModule`, `FormsModule`) and Clarity UI modules.

- **Feature Modules (Conceptual):** The architecture is designed for developers to create new feature modules (e.g., `DashboardModule`, `AdminModule`). These modules encapsulate all the components, services, and routing related to a specific business domain. They are typically **lazy-loaded** to improve initial application load performance.

## Data Architecture

### Primary Database
- Not applicable. As a frontend-only boilerplate, this project does not include a database. It is designed to connect to any backend with a data persistence layer.

### Data Model (Client-Side)
- Data models will be defined using **TypeScript interfaces or classes** within feature modules. These models will represent the structure of data objects retrieved from or sent to the backend API.
- **Example `User` model:**
  ```typescript
  export interface User {
    id: number;
    name: string;
    email: string;
    role: 'admin' | 'user';
  }

  Of course. Here is the architecture_document.md for the Angular Clarity boilerplate project, presented in a single code block for easy copying.

Markdown

# Architecture Document
Generated: Tuesday, September 16, 2025

## System Overview
The Angular Clarity Boilerplate is a frontend-only, single-page application (SPA) template. It is designed to serve as a foundational starting point for developing enterprise-grade web applications. The system provides a pre-configured, modular, and scalable architecture using the Angular framework and is visually styled with the VMware Clarity Design System. Its primary purpose is to accelerate development by providing a structured and feature-rich starting point.

## Architecture Pattern
The boilerplate is built upon a **Component-Based Architecture**, which is fundamental to the Angular framework. The UI is composed of a tree of reusable and encapsulated components.

The overall architectural pattern follows best practices for scalable Angular applications, emphasizing a **Modular Design**. The application is segregated into a `CoreModule`, a `SharedModule`, and is designed for the addition of multiple `FeatureModules`. This structure promotes separation of concerns, reusability, and maintainability.

## Component Design (Frontend)

- **AppModule:** The root module of the application, responsible for bootstrapping the `AppComponent` and importing essential modules like the `CoreModule` and `AppRoutingModule`.

- **AppComponent:** The main application shell component. It contains the primary layout, including the Clarity header, sidebar navigation, and the main content area where routed components are displayed via `<router-outlet>`.

- **CoreModule:** This module is designed to be imported only once by the `AppModule`. It contains singleton services, route guards, and other one-time setup logic (e.g., HTTP interceptors). This pattern prevents services from being provided multiple times across the application.

- **SharedModule:** This module contains commonly used components, directives, and pipes that can be reused across different feature modules. It is imported by feature modules whenever they need access to these shared elements. It primarily exports common Angular modules (like `CommonModule`, `FormsModule`) and Clarity UI modules.

- **Feature Modules (Conceptual):** The architecture is designed for developers to create new feature modules (e.g., `DashboardModule`, `AdminModule`). These modules encapsulate all the components, services, and routing related to a specific business domain. They are typically **lazy-loaded** to improve initial application load performance.

## Data Architecture

### Primary Database
- Not applicable. As a frontend-only boilerplate, this project does not include a database. It is designed to connect to any backend with a data persistence layer.

### Data Model (Client-Side)
- Data models will be defined using **TypeScript interfaces or classes** within feature modules. These models will represent the structure of data objects retrieved from or sent to the backend API.
- **Example `User` model:**
  ```typescript
  export interface User {
    id: number;
    name: string;
    email: string;
    role: 'admin' | 'user';
  }
Data Flow
API Call: A component's method calls a function in its corresponding service (e.g., userService.getUsers()).

Service Layer: The service uses Angular's HttpClient to make an HTTP request to the backend API.

Data Retrieval: The service receives the HTTP response and typically returns an Observable of the data, typed with the appropriate TypeScript interface.

Component Update: The component subscribes to the Observable. Once the data is received, it updates its local state, triggering Angular's change detection to re-render the template and display the new data.

API Design (Backend Communication)
This boilerplate is backend-agnostic. It is designed to communicate with any backend that exposes a RESTful or GraphQL API.

Communication Protocol
HTTP/HTTPS: Communication is handled via standard HTTP requests using Angular's HttpClient service.

Example Service Implementation
An example of a service making API calls:
// in user.service.ts
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';
import { User } from '../models/user.model';
import { environment } from '../../environments/environment';

@Injectable({
  providedIn: 'root'
})
export class UserService {
  private apiUrl = `${environment.apiBaseUrl}/users`;

  constructor(private http: HttpClient) { }

  getUsers(): Observable<User[]> {
    return this.http.get<User[]>(this.apiUrl);
  }

  getUserById(id: number): Observable<User> {
    return this.http.get<User>(`${this.apiUrl}/${id}`);
  }
}

Error Handling
HTTP interceptors can be provided in the CoreModule to handle API errors globally (e.g., logging errors, redirecting on 401 Unauthorized responses).

Security Architecture
Authentication: Authentication logic (e.g., handling JWTs, interacting with OAuth providers) should be encapsulated within an AuthService provided in the CoreModule.

Authorization (Route Guards): The architecture uses Angular's Route Guards to protect routes. An AuthGuard can be implemented to prevent unauthorized users from accessing certain parts of the application.

Client-Side Security: The boilerplate does not inherently protect against all client-side vulnerabilities. Developers should follow best practices for preventing XSS and CSRF attacks.

Scalability Considerations
Lazy Loading: The architecture strongly encourages the use of lazy-loaded feature modules. This ensures that the initial application bundle size remains small, leading to faster load times. As new features are added, they do not impact the initial load performance.

Modular Design: The strict separation of concerns into Core, Shared, and Feature modules makes the codebase easier to manage, test, and scale as the application grows in complexity.

State Management: For applications with complex state, a state management library like NgRx or Akita can be easily integrated into this architecture without requiring significant refactoring.

---

## ARCHITECTURE UPDATE - 2025-10-15 12:34:13

## Component Design Refinements
Generated: 2025-10-15T12:35:00.000000
### Backend Service Interactions
-   **Internal Communication (Modular Monolith):** Initially, services (Product, Order, User/Auth, Audit) will communicate directly within the FastAPI application through shared data models and service calls, leveraging dependency injection for clear boundaries.
-   **Future Microservices Communication:** If services are decoupled into distinct microservices, inter-service communication will shift to asynchronous messaging (e.g., RabbitMQ, Kafka) for event-driven updates (e.g., Order Placed event triggers Inventory Update) and synchronous REST calls for direct data lookups.

### Frontend Module Breakdown
-   **AuthModule:** Will handle user authentication flows (login, registration, password reset), JWT token management (storage, refresh), and expose authentication state and user roles to other modules.
-   **CoreModule:** Will provide global services like logging, API interceptors (for JWT and error handling), and configuration management.
-   **SharedModule:** Reusable UI components (e.g., loading spinners, pagination controls, custom form elements), directives, and pipes that are presentation-agnostic.

## Data Architecture Enhancements
Generated: 2025-10-15T12:35:00.000000
### Database Indexing Strategy
-   **Primary Keys:** All primary keys (`id`) will have clustered indexes by default.
-   **Foreign Keys:** Indexes will be created on all foreign key columns (e.g., `user_id` in Order, `product_id` in OrderItem, `category_id` in Product, `user_id` in AuditLog) to optimize join operations.
-   **Frequently Queried Fields:** Non-clustered indexes will be created on frequently queried fields, such as:
    -   `username`, `email` in `User` table.
    -   `name`, `category_id`, `is_active` in `Product` table.
    -   `order_date`, `status` in `Order` table.
    -   `timestamp`, `action`, `entity_type` in `AuditLog` table.
-   **Search Optimization:** Consider `GIN` or `BRIN` indexes on `JSONB` columns if structured product attributes or order metadata are stored in JSONB. PostgreSQL's full-text search capabilities will be used for efficient product and order searching.

## API Design Standards
Generated: 2025-10-15T12:35:00.000000
### Error Response Standard
-   All API error responses will follow a consistent JSON structure, including:
    ```json
    {
      "code": "string_error_code",
      "message": "Human-readable error description",
      "details": { /* Optional: specific field errors or additional context */ }
    }
    ```
    Examples: `400 Bad Request`, `401 Unauthorized`, `403 Forbidden`, `404 Not Found`, `422 Unprocessable Entity` (for validation errors), `500 Internal Server Error`.
### API Versioning
-   API endpoints will be versioned using path-based versioning (e.g., `/api/v1/products`). This ensures backward compatibility as the API evolves.
### Pagination and Filtering
-   All list endpoints (e.g., `GET /api/products`, `GET /api/orders`, `GET /api/admin/audit-logs`) will support pagination parameters (`limit`, `offset` or `page`, `pageSize`) and filtering parameters (e.g., `?status=pending`, `?category_id=uuid`).

## Security Architecture Refinements
Generated: 2025-10-15T12:35:00.000000
-   **JWT Token Refresh:** Implement a mechanism for refreshing access tokens using longer-lived refresh tokens to enhance security and user experience without frequent re-authentication. Refresh tokens will be stored securely (e.g., HTTP-only cookies).
-   **Rate Limiting:** Implement rate limiting on critical endpoints (e.g., login, registration, password reset) to mitigate brute-force attacks and prevent API abuse.
-   **Content Security Policy (CSP):** Implement a robust CSP on the frontend to prevent cross-site scripting (XSS) and other content injection attacks.
-   **OWASP Top 10 Protections:** Beyond input validation, implement specific protections against common vulnerabilities such as broken authentication, sensitive data exposure, security misconfiguration, and insufficient logging and monitoring.

## Scalability and Performance Enhancements
Generated: 2025-10-15T12:35:00.000000
-   **Database Connection Pooling:** Utilize a robust connection pooler (e.g., PgBouncer alongside SQLAlchemy) to efficiently manage database connections, reducing overhead and improving database performance under heavy load.
-   **Caching Strategy (Redis):** Implement a cache-aside pattern where application logic first checks Redis for data before querying the primary database. This is particularly effective for read-heavy operations like fetching product listings or popular items. Cache invalidation strategies will be employed to ensure data freshness.
-   **Asynchronous Task Queue (Celery/RabbitMQ):** For computationally intensive or time-consuming operations (e.g., bulk product imports, complex report generation, sending mass notifications, processing large orders), integrate an asynchronous task queue like Celery with RabbitMQ (or Kafka) to offload these tasks from the main request-response cycle. This improves API responsiveness and overall system throughput.


---

## ARCHITECTURE UPDATE - 2025-10-15 12:35:15


# Architecture Document
Generated: 2025-10-15T12:31:51.000000

## System Overview
The system will evolve the existing Angular Clarity Boilerplate into a full-featured e-commerce application. It comprises a decoupled frontend Single-Page Application (SPA) built with Angular and the Clarity Design System, and a robust backend API service. The application supports both customer-facing functionalities (product browsing, cart, checkout, user profiles) and secure administrator functionalities (product, order, user management, audit logging).

## Architecture Pattern
*   **Frontend:** Single-Page Application (SPA) using Angular, adhering to the established modular architecture (Core, Shared, Feature modules) from the boilerplate. This promotes maintainability, reusability, and clear separation of concerns.
*   **Backend:** A **Layered Monolithic Architecture** will be adopted for the backend service. This pattern provides a clear separation of concerns (Presentation, Application, Domain, Infrastructure layers), facilitates structured development, and allows for scalability while keeping deployment manageable initially. It also provides a solid foundation for future transition to microservices if the application's scale demands it.

## Component Design
### Frontend (Angular - Extending Boilerplate)
*   **AppModule:** Root module, orchestrating main application components and routing.
*   **CoreModule:** (Extended) Provides singleton services (e.g., `AuthService`, `ErrorHandlingService`, `NotificationService`), HTTP interceptors for authentication and error handling, and guard services for route protection (e.g., `AuthGuard`, `AdminGuard`).
*   **SharedModule:** (Extended) Declares and exports reusable UI components (e.g., custom form controls, data display components, loading indicators using Clarity components), pipes, and directives, ensuring consistency across feature modules.
*   **AuthModule (Feature Module):** Handles user registration, login, logout, password reset flows. Interacts with backend authentication APIs.
*   **ProductCatalogModule (Feature Module):** Responsible for browsing products, displaying product details, search functionality, and filtering options. Uses Clarity Datagrid for product listings in Admin UI.
*   **CartModule (Feature Module):** Manages shopping cart state, adding/removing items, updating quantities, and displaying cart contents.
*   **CheckoutModule (Feature Module):** Guides users through the checkout process, including shipping information, payment integration, and order confirmation.
*   **UserProfileModule (Feature Module):** Allows users to view and manage their profile information, shipping addresses, and review past orders.
*   **AdminModule (Lazy-loaded Feature Module):** Dedicated module for administrator functionalities, protected by `AdminGuard`.
    *   `AdminDashboardComponent`: Provides an overview of key e-commerce metrics (e.g., recent orders, product inventory alerts) using Clarity cards/widgets.
    *   `ProductManagementComponent`: Offers a comprehensive interface for CRUD operations on products, categories, and inventory. Utilizes Clarity Datagrid for product listings and forms for detailed editing/creation.
    *   `OrderManagementComponent`: Enables administrators to view, filter, search, and update the status of customer orders. Displays order details using Clarity layouts.
    *   `UserManagementComponent`: A basic interface to view and manage registered user accounts and roles.

### Backend (Layered Monolith)
*   **Presentation Layer (API Endpoints):** RESTful API endpoints (e.g., Django Views/ViewSets with Django REST Framework) for handling HTTP requests, input validation, and serialization/deserialization of data. Responsible for routing requests to the appropriate application services.
*   **Application Layer (Services):** Contains application-specific business logic and orchestrates domain operations. Examples include `ProductService` (managing product CRUD), `OrderService` (processing orders, updating status), `UserService` (user authentication, profile management, role assignment), and `AuditService` (logging administrative actions).
*   **Domain Layer (Models & Business Rules):** Defines the core business entities (`User`, `Product`, `Order`, `Category`, `AuditLog`, `OrderItem`, `ShippingAddress`) and encapsulates domain-specific business rules (e.g., order status transitions, inventory checks, user role validations).
*   **Infrastructure Layer (Persistence & External Services):** Handles interactions with external systems. This includes database access via ORM (Object-Relational Mapper), integration with third-party payment gateways, email services, and logging frameworks.

## Data Architecture
### Primary Database (PostgreSQL - Relational)
*   **Users Table:** Stores user credentials and profile information.
    *   `id` (PK, UUID), `email` (unique), `password_hash`, `first_name`, `last_name`, `role` (enum: 'customer', 'administrator', default 'customer'), `created_at`, `updated_at`.
*   **Products Table:** Stores product details.
    *   `id` (PK, UUID), `name`, `description`, `price`, `stock_quantity`, `category_id` (FK to Categories), `image_url`, `is_active` (boolean), `created_at`, `updated_at`.
*   **Categories Table:** Stores product categories.
    *   `id` (PK, UUID), `name` (unique), `description`.
*   **Orders Table:** Stores customer order information.
    *   `id` (PK, UUID), `user_id` (FK to Users), `order_date`, `total_amount`, `status` (enum: 'pending', 'processing', 'shipped', 'delivered', 'cancelled'), `shipping_address_id` (FK to ShippingAddresses), `payment_status` (enum: 'pending', 'paid', 'refunded'), `created_at`, `updated_at`.
*   **OrderItems Table:** Stores individual items within an order.
    *   `id` (PK, UUID), `order_id` (FK to Orders), `product_id` (FK to Products), `quantity`, `unit_price` (price at time of order).
*   **ShippingAddresses Table:** Stores shipping addresses for users and orders.
    *   `id` (PK, UUID), `user_id` (FK to Users, nullable), `recipient_name`, `address_line1`, `address_line2` (optional), `city`, `state`, `zip_code`, `country`, `is_default` (boolean).
*   **AuditLogs Table:** Records significant administrative actions (per NFR-006, NFR-007).
    *   `id` (PK, UUID), `user_id` (FK to Users, specifically administrators), `action` (string, e.g., 'PRODUCT_UPDATED', 'ORDER_STATUS_CHANGED'), `entity_type` (string, e.g., 'Product', 'Order', 'User'), `entity_id` (UUID, ID of the affected entity), `old_value` (JSON/Text, optional), `new_value` (JSON/Text, optional), `timestamp`.

### Caching
*   A distributed cache (e.g., Redis) will be used to store frequently accessed, less volatile data such as product lists, category data, and potentially user sessions, reducing database load and improving response times.

### Data Flow
*   The Angular frontend communicates with the backend via RESTful API calls over HTTPS.
*   The backend processes these requests, performs business logic, and interacts with the PostgreSQL database for data persistence and retrieval. Cache is consulted before hitting the database for read operations.
*   Payment processing is offloaded to a third-party gateway, with the backend only storing transaction references and status, not sensitive card details (Assumption 1).

## API Design
All APIs will be RESTful, returning JSON payloads, and accessible via HTTPS.

### Authentication & User Management
*   `POST /api/auth/register`: Register a new customer user.
*   `POST /api/auth/login`: Authenticate user, return JWT token.
*   `POST /api/auth/logout`: Invalidate JWT token (if applicable for server-side token management).
*   `GET /api/users/me`: Retrieve current user's profile (authenticated only).
*   `PUT /api/users/me`: Update current user's profile (authenticated only).

### Product Catalog (Public)
*   `GET /api/products`: Retrieve a list of active products (supports pagination, filtering by category, search by name/description).
*   `GET /api/products/{id}`: Retrieve details of a specific product.
*   `GET /api/categories`: Retrieve a list of product categories.

### Shopping Cart
*   `GET /api/cart`: Retrieve the current user's shopping cart contents (authenticated only).
*   `POST /api/cart`: Add a product to the cart (authenticated only).
*   `PUT /api/cart/{item_id}`: Update quantity of an item in the cart (authenticated only).
*   `DELETE /api/cart/{item_id}`: Remove an item from the cart (authenticated only).

### Order Management (Customer)
*   `POST /api/orders`: Create a new order from the current cart (authenticated only, idempotent per NFR-007).
*   `GET /api/orders`: Retrieve a list of current user's orders (authenticated only).
*   `GET /api/orders/{id}`: Retrieve details of a specific order (authenticated only).
*   `PATCH /api/orders/{id}/cancel`: Request to cancel an order (only if status is 'Pending' or 'Processing' per Business Rule 8).

### Admin Interfaces (Protected by Admin Role)
*   **Product Management:**
    *   `GET /api/admin/products`: List all products (supports pagination, filtering, search).
    *   `POST /api/admin/products`: Create a new product.
    *   `GET /api/admin/products/{id}`: Retrieve product details.
    *   `PUT /api/admin/products/{id}`: Update product details.
    *   `DELETE /api/admin/products/{id}`: Delete a product.
*   **Order Management:**
    *   `GET /api/admin/orders`: List all orders (supports pagination, filtering by status, search by customer/order ID).
    *   `GET /api/admin/orders/{id}`: Retrieve detailed order information.
    *   `PATCH /api/admin/orders/{id}/status`: Update order status (e.g., to 'processing', 'shipped', 'delivered', 'cancelled').
*   **User Management:**
    *   `GET /api/admin/users`: List all users.
    *   `GET /api/admin/users/{id}`: Retrieve user details.
    *   `PATCH /api/admin/users/{id}/role`: Update user roles (e.g., promote to admin).
*   **Audit Logging:**
    *   `GET /api/admin/auditlogs`: Retrieve audit trail of administrative actions.

### API Characteristics
*   **Versioning:** Implicitly `/api/v1` for initial development.
*   **Validation:** Robust input validation for all POST/PUT/PATCH requests (per NFR-007).
*   **Error Handling:** Consistent JSON error responses with appropriate HTTP status codes.
*   **Pagination, Filtering, Sorting:** Supported on all list endpoints (e.g., `/api/products`, `/api/admin/orders`) (per Interface Requirements 4).

## Security Architecture
*   **Authentication:** JWT (JSON Web Tokens) will be used for stateless authentication. Upon successful login, the backend issues a JWT, which the frontend stores (e.g., in `localStorage` or `sessionStorage`) and includes in the `Authorization: Bearer <token>` header for all subsequent API requests.
*   **Authorization (RBAC):** Role-Based Access Control will be implemented.
    *   Backend middleware/decorators will verify user roles ('customer', 'administrator') for accessing specific API endpoints. Admin-specific endpoints (`/api/admin/*`) will be strictly protected to ensure only authenticated users with the 'administrator' role can access them (Business Rules - Admin & Operations).
    *   Frontend route guards will prevent unauthorized navigation to admin sections.
*   **Data Protection:**
    *   All communication between frontend and backend will be secured using HTTPS (SSL/TLS).
    *   User passwords will be stored as securely hashed values (e.g., using bcrypt) in the database.
    *   Input validation on both frontend and backend to prevent common vulnerabilities like XSS, SQL injection, and buffer overflows.
*   **Auditability & Logging:** Per NFR-006 and NFR-007, all critical administrative actions (product CRUD, order status changes, user role updates) will be logged to the `AuditLogs` table, including timestamp, administrator ID, and details of the change. System errors and security-sensitive events (failed logins) will also be logged.
*   **Payment Security:** Integration with a PCI DSS compliant third-party payment gateway (e.g., Stripe, PayPal) to offload sensitive credit card information handling and minimize the application's PCI scope (Assumption 1).

## Scalability Considerations
*   **Frontend Scaling:** Angular application bundles will be optimized for production (tree-shaking, minification, AOT compilation). Can be served via CDN for global performance.
*   **Backend Horizontal Scaling:** The backend services will be designed to be stateless, allowing multiple instances to run concurrently behind a load balancer. This enables horizontal scaling to handle increased traffic.
*   **Database Scaling:** Initially, a single PostgreSQL instance. For increased read loads, read replicas can be added. For extreme scale, database sharding or specialized services may be considered.
*   **Caching Layer:** Redis will act as a distributed cache to reduce the load on the database for frequently accessed data (e.g., product catalog, popular items).
*   **Load Balancing:** An Application Load Balancer (ALB) will distribute incoming requests across multiple backend service instances, enhancing availability and performance.
*   **Asynchronous Processing:** For non-critical, time-consuming tasks (e.g., sending order confirmation emails, processing inventory updates), message queues (e.g., RabbitMQ, AWS SQS) can be introduced to decouple services and improve API responsiveness.
*   **Containerization:** Docker will containerize both frontend and backend applications, ensuring consistent environments from development to production and facilitating orchestration with tools like Kubernetes for auto-scaling and high availability.


---

## ARCHITECTURE UPDATE - 2025-10-15 12:36:01


# Architecture Document Update
Generated: 2025-10-15T12:40:00.000000

## API Design Refinement
Building on the existing API design, specific attention is drawn to the idempotency of critical write operations. As per the `requirements_document.md` under "Interface Requirements" -> "4. API Interface (Backend) Enhancements", `POST /api/orders` and other state-changing operations will be designed to be idempotent. This ensures that repeated identical requests, due to network issues or user error, do not lead to unintended duplicate resource creation or state changes, thereby enhancing data integrity and user experience.

## Security Architecture Enhancements
Further emphasizing data protection, the design adheres to `analysis_document.md` Assumption 1 by ensuring that sensitive payment card information is **never** processed, stored, or transmitted by the application itself. The application strictly relies on PCI DSS compliant third-party payment gateways (e.g., Stripe, PayPal), significantly minimizing the application's PCI compliance scope and reducing security risks. This clear separation of payment concerns is a critical design choice.

## Scalability Considerations for E-commerce Traffic
To further address scalability, especially for an e-commerce application prone to seasonal spikes or promotional events, the asynchronous processing capability (e.g., via Celery with Redis/RabbitMQ as mentioned in the Tech Stack) will be leveraged for non-critical, time-consuming tasks such as order confirmation email delivery, inventory reconciliation after order fulfillment, and potentially report generation. This ensures that the primary API endpoints remain highly responsive to user requests, aligning with the "Shoppers (End-Users)" stakeholder interest in a seamless experience.

