Financial SaaS : Automated Trading recommendation system - Secure Alpaca OAuth 2.0 Integration & Push Alerts

Build a "Trading Terminal" SaaS application where retail users can receive automated algorithmic trade alerts and manually authorize them with a single click. Or implement an automatic trigger in their own account. My AI tool has successfully built the frontend dashboard layout, user profiles, and standard database schema. I need a vetted human developer to cross the finish line by handling the critical integration, real-time networking, and security layers. Key Deliverables for This Job:     1    Alpaca Connect OAuth 2.0 Setup: Configure the formal OAuth handshake redirect via the backend using account:write and trading scopes.     2    Secure Token Storage: Implement robust backend encryption (AES-256) to store user access and refresh tokens at rest in our PostgreSQL database. Write an automated token-refresh function to handle 401 Unauthorized responses gracefully.     3    Real-Time Push Alerts : Connect a Python/FastAPI signal ingestion endpoint to a Node.js notification core. When an external algorithm hits our webhook, it must broadcast real-time pop-ups to the web UI (WebSockets) and dispatch native interactive push notifications via Firebase Cloud Messaging.     4    Order Routing Loop: Ensure that when a user taps "Approve" on the notification (via deep link or web UI), the system routes a secure execution order to Alpaca's /v2/orders API using that user's specific OAuth token. Testing Requirement: All execution routines must be fully validated and sandboxed inside the Alpaca Paper Trading environment before final hand-off.

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