A secure, real-time auction system with race-condition prevention, built with FastAPI, GraphQL, PostgreSQL, Redis, and WebSockets.

graph TB
    Client[Client Applications] --> |HTTP/WebSocket| API[FastAPI Server]
    API --> |GraphQL| GraphQL[Strawberry GraphQL]
    API --> |ORM| DB[(PostgreSQL)]
    API --> |Cache/PubSub| Redis[(Redis)]
    API --> |Background Tasks| Celery[Celery Workers]
    Celery --> |Task Monitoring| Flower[Flower Dashboard]
    API --> |Real-time Updates| WS[WebSocket Manager]
    WS --> |Bid Updates| Client
    GraphQL --> |Mutations/Queries| API

• Secure Bidding: Atomic operations with Redis locks
• Real-time Updates: WebSocket connections for live bid updates
• Race Condition Prevention: Optimistic locking and distributed locks
• Background Processing: Celery for auction end processing
• GraphQL API: Structured queries and mutations
• Caching: Redis for session management and caching
• Monitoring: Flower dashboard for task monitoring

• FastAPI - HTTP/WebSocket APIs
• Strawberry GraphQL - GraphQL schema and resolvers
• PostgreSQL - Relational storage with SQLAlchemy
• Redis - Caching, pub/sub, and distributed locks
• WebSockets - Real-time bid updates
• Celery + Flower - Background task processing
• Firebase Scheduled Functions - Periodic checks (coming soon)

• JWT authentication
• Rate limiting
• Input validation
• SQL injection prevention
• XSS protection
• CSRF protection
• Secure WebSocket connections