System Architecture

Architecture Overview

HubNest CRM is built on a modern, decoupled service-oriented architecture designed to handle high concurrency, multi-tenant workspace isolation, and high-performance CRM operations.

graph TD
    Client[Next.js Client app] -->|HTTPS / WSS| Gateway[Nginx / API Gateway]
    Gateway -->|Auth & Routing| Server[Express.js App Server]
    Server -->|Read/Write Queries| DB[(PostgreSQL Database)]
    Server -->|Caching & Queues| Redis[(Redis InMemory cache)]
    Server -->|Transactional SMS| Twilio[Twilio SMS Gateway]
    Server -->|Transactional Mail| Mail[SMTP / Resend Gateway]

Core Components

1. Frontend Client (Next.js)

• Framework: Next.js 16 (Turbopack) & React 19.
• State Management: Zustand for global state, React Context for themes.
• Styling: Tailwind CSS v4 featuring premium dark-mode custom color overrides.
• Client Storage: Dexie (IndexedDB wrapper) for offline caching and high-availability operations.

2. Backend Server (Express.js)

• Engine: Node.js v20+ with Express.
• ORM / Query Builder: Knex / pg-pool for optimized connection pooling and migrations.
• Authentication: Stateless JSON Web Tokens (JWT) combined with Secure HTTPOnly Cookies.

3. Data Tier (PostgreSQL & Redis)

• PostgreSQL: Stores relational transactional data (Users, Tenants, Leads, Invoices, Departments).
• Redis: Handles session storage, rate limiting, and caching of high-frequency datasets (like active subscription parameters).

4. Event Processing

• BullMQ backed by Redis for background tasks, such as generating email campaigns and tracking webhook retries.