Architecture

Event-Driven Distributed Node.js Backend Architecture

System Flow Diagram

Client Request → NGINX Load Balancer → Node.js Cluster (PM2)
                                                      ↓
                                              Redis Pub/Sub
                                                      ↓
                                           BullMQ Async Workers

Request Workflow & Logic

API traffic is distributed by NGINX across multiple Node.js server nodes. Heavy processing jobs are offloaded to Redis-backed queues (BullMQ). Distributed workers process queue tasks asynchronously, notifying clients via WebSockets.

Engineering Considerations

Thread Management

Avoid processing heavy data calculation on the main single-thread loop. Offload to workers.

Cluster Mode

Configure PM2 cluster mode to run one process per CPU core, maximizing server resource use.

Connection Pools

Re-use database connections to avoid exhausting database ports under heavy load.

Recommended Infrastructure Stack

Service	Purpose / Role
AWS EC2 instances	Compute instances running Docker-packaged Node.js app containers.
Redis ElastiCache	Powers BullMQ task queues and WebSocket communication channels.
PostgreSQL RDS	Primary database for storing persistent application records.

Security Isolation Policy

Configure JWT validation checks in custom API middleware to reduce database load.

DevOps & Deployment Configuration

Automate container releases using Docker Compose and Docker Hub registries.