Full-Stack Real-Time Crypto Pricing Monitor

A production-ready proof-of-concept demonstrating modern .NET and Angular patterns with full persistence, user management, and alerting capabilities.

Architecture Overview

This project implements a real-time cryptocurrency price monitoring system using a decoupled, event-driven architecture. It leverages .NET Aspire for orchestration and features a high-performance .NET backend paired with a reactive, zoneless Angular frontend.

┌─────────────────────────────────────────────────────────────────────────────────────────┐
│                                   .NET Aspire AppHost                                   │
│  ┌──────────────┐  ┌──────────────┐  ┌─────────────────────────────┐  ┌──────────────┐  │
│  │    Redis     │  │  PostgreSQL  │  │     Backend API (NET 9)     │  │ Angular SPA  │  │
│  │  (caching)   │  │ (persistence)│  │   Clean Architecture + CQRS │  │  (Zoneless)  │  │
│  └──────┬───────┘  └──────┬───────┘  └──────────────┬──────────────┘  └──────┬───────┘  │
└─────────┼─────────────────┼─────────────────────────┼────────────────────────┼──────────┘
          └─────────────────┴───────────┬─────────────┘                        │
                                        ▼                                      │
                                 [ SignalR / REST ] ◄──────────────────────────┘

Tech Stack

Backend (.NET 9 / Aspire)

• Clean Architecture - Domain, Application, Infrastructure, API layers.
• ASP.NET Core Identity - Secure JWT-based authentication with Refresh Token support for user management.
• EF Core + Npgsql - Relational persistence with PostgreSQL for users, watchlists, and price history.
• Redis - High-performance caching for real-time alerts and state management.
• CQRS with MediatR - Clean separation of read and write operations for scalability.
• System.Threading.Channels - Bounded backpressure management for resilient price streams.
• SignalR - Real-time WebSocket broadcasting of market data to connected clients.
• Polly - Advanced resilience with Retry and Circuit Breaker policies for external dependencies.

Frontend (Angular 19 Zoneless)

• Zoneless Bootstrap - Zero Zone.js overhead for peak rendering performance.
• Angular Signals - Fine-grained reactive state management across all components.
• Signal Store - Structured state management using @ngrx/signals for Auth and Price modules.
• Atomic Design - Highly structured and reusable component architecture (Atoms -> Molecules -> Organisms).

How to Run

Prerequisites

• .NET 9.0 SDK or later
• Bun (https://bun.sh)
• Docker (for PostgreSQL and Redis containers via Aspire)

Quick Start

1. Install Bun dependencies for the Angular frontend:

   cd frontend
   bun install

2. Run via .NET Aspire (recommended):

   cd backend/CryptoSimulator.AppHost
   dotnet run

3. Open the Aspire Dashboard (URL shown in console)

Solution Structure

CryptoSimulator/
├── backend/
│   ├── CryptoSimulator.AppHost/         # Aspire orchestration & dependency wiring
│   ├── CryptoSimulator.ServiceDefaults/ # Shared telemetry & resilience config
│   └── src/
│       ├── CryptoSimulator.Domain/      # Aggregates (User, WatchlistItem, CryptoPrice), Value Objects, Events
│       ├── CryptoSimulator.Application/ # CQRS Commands, Queries, Logic Handlers
│       ├── CryptoSimulator.Infrastructure/ # Persistence (EF Core), Caching (Redis), Workers
│       └── CryptoSimulator.Api/         # Minimal APIs, Endpoints, Middleware
│
└── frontend/                            # Angular Zoneless SPA
    └── src/
        └── app/
            ├── core/                    # Global Services, Stores (Auth, Price), Interceptors
            ├── features/                # Auth & Watchlist functional modules
            └── ui/                      # UI Components (Atoms, Molecules, Organisms)

Key Architectural Patterns

Pattern	Location	Why
Backpressure	PriceChannel.cs	Prevents producer from overwhelming consumers in the price stream.
CQRS	Application handlers	Decouples read and write logic, enabling independent scaling and optimization.
Identity	AddIdentityCore	Provides standardized, secure user management and token-based auth.
Persistence	ApplicationDbContext	Ensures reliable data storage and history tracking using EF Core and PostgreSQL.
Caching	RedisAlertCacheService	Enables low-latency access and distributed state for real-time alerting.
Resilience	PollyPolicies.cs	Handles transient failures and external service outages gracefully.
Zoneless	app.config.ts	Eliminates change detection overhead by removing Zone.js dependencies.

Endpoints

Authentication

Method	Endpoint	Description
POST	/api/auth/register	Register a new user
POST	/api/auth/login	Authenticate and get JWT/Refresh tokens
POST	/api/auth/refresh	Refresh an expired access token

Prices

Method	Endpoint	Description
GET	/api/prices	Get current prices for all tracked assets
GET	/api/prices/{symbol}	Get detailed historical and current data for a specific asset
WS	/hubs/prices	SignalR hub for real-time market updates

Watchlist

Method	Endpoint	Description
GET	/api/watchlist	Get current user's personalized watchlist
POST	/api/watchlist	Add a specific cryptocurrency symbol to the watchlist
DELETE	/api/watchlist/{symbol}	Remove a symbol from the watchlist

License

MIT License - Built for learning purposes and demonstration of high-performance web architecture.