🚀 LinkUp: The Backend Engine

A high-performance, asynchronous REST and WebSocket API built with FastAPI. This backend powers the LinkUp ecosystem with real-time matching, secure authentication, and scalable messaging infrastructure.

  

🌟 Project Highlights & Technical Differentiators

This project demonstrates expertise in asynchronous Python development, complex database orchestration, and real-time event-driven architecture.

Feature	Technical Implementation	Engineering Value Demonstrated
Asynchronous Core	FastAPI + AsyncPG connection pooling	High-concurrency handling, non-blocking I/O, optimized throughput
Real-Time Events	WebSockets with polymorphic event validation via TypeAdapter	Robust real-time messaging, typing indicators, and read receipts
Low-Latency Caching	Redis integration for state management	Reduced database load, fast access to transient session data
Task Orchestration	APScheduler for cron-based background jobs	Reliable execution of periodic events (e.g., "Meet at 8" lobby)

🧱 Architecture Overview: Asynchronous Micro-services

The backend is structured to handle high-frequency swiping and messaging through a modern, modular design.

API Entry & Middleware (app/main.py)

• Orchestrates the app lifecycle, managing the database pool and background schedulers.
• Implements versioned routing (/api/v1) for seamless future updates.
• Serves static assets for legal and safety documentation.

Websocket Layer (app/routes/chats, app/routes/matches)

• Chat Socket — Manages persistent bi-directional connections for messaging, supporting text content, media metadata, and delivery states.
• Lobby Socket — Powers the synchronous matchmaking lobby with automated waiting periods.

Utility & Logic Layer (app/utilities)

• Security — Implements JWT-based authentication and secure password hashing.
• Data Validation — Leverages Pydantic for strict schema enforcement across all REST and WebSocket payloads.

⚙️ Core Modules & Components

Module	Purpose	Key Files
Auth Service	Multi-stage registration and secure login	auth_endpoints.py, auth_utilities.py
Match Engine	Location-based filtering and swipe logic	swipe_endpoint.py, matches_utilities.py
Chat Service	Persistence and delivery of real-time interactions	chat_websocket_endpoints.py, chat_utilities.py
Controller Layer	Interface for PostgreSQL, Redis, and Cloud Storage	db_controller.py, redis_controller.py

🛠️ Development Setup

Requires Python 3.11+.

1. Installation

  git clone https://github.com/olildu/linkup-backend.git
  cd linkup-backend
  pip install -r requirements.txt

2. Configuration

  DB_HOST=localhost
  DB_NAME=linkup
  REDIS_URL=redis://localhost:6379
  SECRET_KEY=your_secret_key

3. Running the Server

  uvicorn app.main:app --reload

📱 Ecosystem Logic

LinkUp Backend is designed to maintain high availability and data integrity through the following mechanisms:

• Connection Resilience:
  WebSocket connections handle disconnects gracefully, ensuring no messages are lost during network transitions or temporary network failures.

• Automated Maintenance:
  APScheduler manages the daily lifecycle of matching events, ensuring consistent engagement and timely updates for the user base.

• Data Protection:
  All user interactions are strictly validated using Pydantic models before reaching the persistence layer, preventing malformed or unsafe data from being stored.