# Technology Stack Document
Generated: Tuesday, September 16, 2025

## Frontend Technologies

* **Framework:** **Angular**. The boilerplate is built on the latest stable version of the Angular framework, chosen for its robustness, component-based architecture, and suitability for large-scale, enterprise applications.
* **Language:** **TypeScript**. As a superset of JavaScript, TypeScript is used for its strong typing, which improves code quality, maintainability, and developer productivity.
* **Styling:** **SCSS**. SCSS is used for its advanced features over standard CSS, such as variables, nesting, and mixins, allowing for more organized and maintainable stylesheets.
* **UI Framework:** **VMware Clarity Design System**. This comprehensive design system provides a set of accessible, high-quality UI components and a consistent visual language, which accelerates UI development.
* **Core Libraries:**
    * **RxJS:** Used extensively throughout Angular for reactive programming and managing asynchronous operations.
    * **Zone.js:** A signaling mechanism that enables Angular's automatic change detection.

## Backend Technologies

* **Backend Agnostic:** This is a frontend-only boilerplate and is not tied to any specific backend technology. It is designed to communicate with any backend that exposes a RESTful or GraphQL API.

## Database Technologies

* **Not Applicable:** As a frontend project, the boilerplate does not include a database.

## Infrastructure & Deployment

* **Web Server:** The built application consists of static files that can be served by any modern web server (e.g., **Nginx**, **Apache**, **Caddy**).
* **Hosting:** The project can be deployed to any static site hosting provider, such as **Firebase Hosting**, **Netlify**, **Vercel**, **AWS S3**, or **GitHub Pages**.
* **Containerization (Optional):** The application can be easily containerized using **Docker** for consistent deployment environments.

## Development & Build Tools

* **Build Tool:** **Angular CLI**. The command-line interface for Angular is used for creating, building, testing, and deploying the application.
* **Package Manager:** **npm**. The Node Package Manager is used for managing all project dependencies.
* **Version Control:** **Git**. Git is the standard for version control and source code management.
* **Testing:**
    * **Unit Testing:** **Jasmine** (framework) and **Karma** (test runner) are the default tools for unit testing in Angular.
    * **End-to-End (E2E) Testing:** The project can be configured to use **Protractor** or more modern alternatives like **Cypress** or **Playwright**.
* **Code Formatting/Linting:**
    * **ESLint:** Used for identifying and reporting on patterns in ECMAScript/JavaScript code.
    * **Prettier:** An opinionated code formatter that enforces a consistent style.
    * **EditorConfig:** Helps maintain consistent coding styles for multiple developers working on the same project across various editors and IDEs.

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## TECH STACK UPDATE - 2025-10-10 04:19:30


# Technology Stack Document
Generated: 2025-10-10T04:04:10.080488

## Frontend Technologies - 2025-10-10T04:04:10.080488
-   **Framework:** Angular (v16+). Leverages the existing Angular Clarity Boilerplate.
-   **UI Library:** VMware Clarity Design System (already integrated in boilerplate).
-   **Reactive Programming:** RxJS for managing asynchronous data streams and events.
-   **State Management:** Angular Services + RxJS for local component state; NgRx (Store, Effects) if global, complex state management becomes necessary for advanced features.
-   **HTTP Client:** Angular `HttpClient` for REST API interactions.
-   **Real-time Client:** Custom Angular service leveraging native `WebSocket` API or a library wrapper (e.g., `ngx-socket-io`) for WebSocket communication.

## Backend Technologies - 2025-10-10T04:04:10.080488
-   **Language:** Python 3.9+.
-   **Framework:** FastAPI (for REST API services) and Starlette/websockets library (for WebSocket Gateway) due to its high performance, async capabilities, and excellent developer experience. Alternatively, Django Channels could be considered if a more monolithic Python backend is preferred, but FastAPI with dedicated WebSocket handling offers better microservice alignment.
-   **API Type:** RESTful API for standard operations; WebSocket for real-time communication.
-   **Authentication:** `PyJWT` for JSON Web Token handling. `Passlib` for password hashing (bcrypt).
-   **ORM/Database Client:** SQLAlchemy 2.0 with Alembic for migrations, or Tortoise ORM for async support with FastAPI.
-   **Message Broker Client:** `Pika` (for RabbitMQ) or `confluent-kafka-python` (for Kafka).

## Database Technologies - 2025-10-10T04:04:10.080488
-   **Primary Database:** PostgreSQL (v14+) for its robustness, advanced features (JSONB), and strong support for relational data and scalability. Suitable for `User`, `Conversation`, `ConversationParticipant`, and `Message` entities.
-   **Caching/Real-time Data Store:** Redis (v7+) for user presence, session management, Pub/Sub for WebSocket scaling, and general-purpose caching. Crucial for low-latency real-time features.
-   **Object Storage (Future for Media Sharing):** Amazon S3, Google Cloud Storage, or a compatible MinIO instance for storing image and file attachments (`FR-017`).

## Infrastructure - 2025-10-10T04:04:10.080488
-   **Containerization:** Docker for packaging all frontend and backend services into isolated containers.
-   **Orchestration (Development/Local):** Docker Compose for defining and running multi-container Docker applications locally.
-   **Orchestration (Production):** Kubernetes (e.g., AWS EKS, Azure AKS, GCP GKE) for scalable, fault-tolerant deployment of microservices, or AWS ECS/Fargate for managed container orchestration for simpler deployments.
-   **Hosting:** Cloud provider like AWS, Azure, or GCP.
-   **Load Balancer/Reverse Proxy:** Nginx for HTTP/HTTPS load balancing and SSL termination for REST API and WebSocket connections.
-   **CI/CD:** GitHub Actions or GitLab CI/CD for automated testing, building, and deployment pipelines.

## Development Tools - 2025-10-10T04:04:10.080488
-   **Version Control:** Git (GitHub/GitLab/Bitbucket).
-   **IDE:** Visual Studio Code with relevant Angular, Python, Docker extensions.
-   **Frontend Testing:** Jest/Karma (Unit testing), Cypress/Playwright (E2E testing).
-   **Backend Testing:** Pytest (Unit/Integration testing).
-   **API Documentation:** OpenAPI/Swagger UI (FastAPI provides this automatically).
-   **Linting/Formatting:** ESLint/Prettier (Frontend), Black/Flake8/isort (Backend).



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## TECH STACK UPDATE - 2025-10-10 04:20:49


# Technology Stack Document Update: Messaging App
Generated: 2025-10-10T[timestamp]

## Frontend Technologies
-   **Framework:** Angular (v12+), leveraging the existing Angular Clarity Boilerplate structure and tools.
-   **Styling:** VMware Clarity Design System (CSS components and styles).
-   **State Management:** RxJS for reactive programming and managing application state, Angular Services for shared data logic. Potentially NgRx for more complex global state management in later phases if needed.
-   **Real-time Client:** Native WebSocket API through Angular services, potentially using `ngx-web-socket` or a similar wrapper for streamlined integration.

## Backend Technologies
-   **Language:** Python 3.9+ (Chosen for its robust ecosystem, excellent asynchronous capabilities, and developer productivity, making it suitable for a real-time application).
-   **Framework:** FastAPI (High-performance web framework for building APIs with Python 3.7+ based on standard Python type hints. Ideal for RESTful APIs and seamless integration with WebSockets due to its ASGI nature).
-   **API:**
    -   **RESTful API:** Implemented with FastAPI for authentication, user management, and historical data retrieval.
    -   **WebSocket API:** Implemented using FastAPI's built-in Starlette WebSocket capabilities for real-time messaging and presence.
-   **ORM/Database Client:** SQLAlchemy with Alembic for migrations (for PostgreSQL interaction, offering robust ORM capabilities and database schema management).
-   **Password Hashing:** `bcrypt` library.
-   **JWT Handling:** `python-jose` or `PyJWT` for token generation and validation.

## Database Technologies
-   **Primary Database:** PostgreSQL (Chosen for its reliability, advanced features like JSONB, robust transaction support, and strong scalability for relational data. Suitable for storing user, conversation, and message data).
-   **Caching/Message Broker:** Redis (Used for storing user presence data, serving as a Pub/Sub message broker for real-time event distribution across WebSocket instances, and for general-purpose caching).

## Infrastructure
-   **Deployment:**
    -   **Containerization:** Docker (All frontend and backend services will be containerized).
    -   **Orchestration (Local/Dev):** Docker Compose (For defining and running multi-container Docker applications for local development and staging environments).
    -   **Orchestration (Production):** Kubernetes or AWS ECS/Fargate (Future consideration for highly scalable and resilient production deployments, allowing for horizontal scaling of backend and WebSocket services).
-   **Hosting:** Cloud-agnostic design, with potential deployment on AWS, Azure, or GCP. For media storage (Phase 2), cloud-native object storage like AWS S3 or Google Cloud Storage will be utilized.
-   **Reverse Proxy/Load Balancer:** Nginx (To serve the Angular frontend, proxy API requests to backend services, and manage WebSocket connections, handling SSL termination).

## Development Tools
-   **Version Control:** Git (GitHub/GitLab/Bitbucket for repository hosting).
-   **Testing:**
    -   **Frontend:** Jest / Karma & Jasmine (For Angular unit and integration tests).
    -   **Backend:** Pytest (For Python backend unit, integration, and API tests).
-   **CI/CD:** GitHub Actions / GitLab CI / Jenkins (To automate testing, building, and deployment pipelines).
-   **Code Quality:** Prettier, ESLint (Frontend); Black, Flake8 (Backend) for code formatting and linting.
-   **API Documentation:** FastAPI's automatic OpenAPI (Swagger UI/ReDoc) generation for backend API documentation.



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## TECH STACK UPDATE - 2025-10-10 04:21:29



# Technology Stack Document Update
Generated: 2025-10-10T04:20:00.000000

## Monitoring & Logging Tools
To address NFR-005 (Reliability) and NFR-006 (Maintainability) and provide crucial operational insights, the following tools will be integrated:

*   **Metrics & Dashboards:** Prometheus (for time-series data collection from backend services, database, Redis) and Grafana (for visualizing metrics and creating interactive dashboards). FastAPI's `Prometheus-FastAPI-Instrumentator` can be used for easy integration.
*   **Centralized Logging:** Loki (for log aggregation) with Promtail (for shipping logs from containers) or Elasticsearch, Logstash, Kibana (ELK Stack) for comprehensive log management, search, and analysis.
*   **Error Tracking:** Sentry (or similar) for real-time error tracking and alerting in both frontend (Angular) and backend (FastAPI) applications.

## CI/CD Pipeline Details
Building on the mention of GitHub Actions/GitLab CI, a more detailed workflow will include:

*   **Linting & Formatting:** Automatic checks (Prettier, ESLint, Black, Flake8) on every pull request or commit to ensure code quality and consistency.
*   **Automated Testing:**
    *   **Unit Tests:** Run Jest/Karma & Jasmine for Angular, Pytest for FastAPI.
    *   **Integration Tests:** API-level tests for backend endpoints and WebSocket interactions.
*   **Container Image Building:** Docker images for frontend (Nginx serving Angular build) and backend (FastAPI application) are built and tagged.
*   **Vulnerability Scanning:** Scan Docker images for known vulnerabilities using tools like Trivy or Clair.
*   **Deployment to Staging:** Automated deployment of new container images to a staging environment for further testing and review.
*   **Production Deployment:** Manual or automated (after successful staging) deployment to the production environment, potentially using Kubernetes deployment manifests or AWS ECS service definitions.

## API Gateway / Reverse Proxy Configuration
Elaborating on Nginx's role in Infrastructure, it will be configured for:

*   **SSL Termination:** Handling HTTPS/WSS encryption and decryption, offloading this CPU-intensive task from backend services.
*   **Load Balancing:** Distributing incoming HTTP and WebSocket traffic across multiple instances of the FastAPI backend and WebSocket services to ensure high availability and scalability (NFR-003, NFR-006).
*   **Request Routing:** Routing `/api/*` requests to the backend services and `/ws/chat` requests to the WebSocket Service, while serving static files for the Angular frontend.
*   **Rate Limiting:** Implementing basic rate limiting policies to protect backend endpoints from abuse and DDoS attacks, directly supporting NFR-002 (Security).

## Future Technology Considerations (Phase 2 & Beyond)

*   **Media Storage:** AWS S3, Google Cloud Storage, or Azure Blob Storage (already mentioned but emphasized for its scalability with FR-017, FR-018).
*   **Background Task Queue:** Celery with Redis for asynchronous task processing, especially for heavy operations like media resizing/processing or complex notification delivery for Phase 2 features.

