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Technical Architecture

Overview

The Conference Expo Portal v2.0 will be built as a modern web application using a monolithic backend architecture with a separate frontend application. This approach provides a good balance between development efficiency and scalability for our current needs. The system consists of:

  • A NestJS-based backend API that handles all business logic, data processing, and external service integrations
  • A Nuxt.js frontend application that provides the user interface
  • Managed services for database, caching, and file storage

This document outlines the technical architecture, technology choices, and infrastructure design.

System Architecture

The system will be built on DigitalOcean's infrastructure, comprising:

  • Frontend: Nuxt.js application
  • Backend: NestJS API
  • Database: Managed PostgreSQL
  • Cache/Queue: Managed Valkey
  • Storage: DigitalOcean Spaces
  • Load Balancing: DigitalOcean Load Balancer

Technology Stack

Frontend

  • Framework: Nuxt.js 4.x

    • Vue.js 3.x
    • TypeScript
    • Tailwind CSS 4.x
    • Composition API

  • Key Features

    • Server-side rendering
    • Type safety with auto-generated TypeScript SDK (Orval)
    • Component-based architecture
    • Responsive design
    • State management
    • Form handling
    • File upload management, including chunking of large (1 GB+) files
    • Type-safe API client with full IntelliSense

Backend

  • Framework: NestJS 11.x

    • Node.js 22.x LTS
    • TypeScript
    • REST API architecture
    • OAuth 2.0 authentication
    • TypeORM
    • Swagger/OpenAPI auto-generation

  • Key Features

    • Business logic implementation
    • Data validation with class-validator
    • Authentication with Passport
    • File processing
    • Background jobs with Bull
    • External service integration
    • Automatic API documentation generation

Database

  • Technology: DigitalOcean Managed PostgreSQL
    • High availability
    • Automated backups
    • Query optimisation
    • Database migrations with TypeORM
    • JSON/JSONB support for flexible data structures
    • Full-text search capabilities

Infrastructure

  • Hosting: DigitalOcean

    • App Platform for frontend
    • Droplets for backend
    • Managed services
    • Load balancer
    • CDN integration

  • Deployment

    • Automated CI/CD
    • Zero-downtime deployments
    • Environment-based configuration
    • Health monitoring

Security Architecture

Authentication

  • OAuth 2.0 via Passport.js
    • Password grant for first-party Nuxt.js application
    • Authorization code grant for third-party API clients
    • Client credentials grant for server-to-server integrations
  • Token-based authentication
    • JWT tokens for stateless authentication
    • Short-lived access tokens (15 minutes) for API requests
    • Long-lived refresh tokens (30 days) for session persistence
    • Refresh tokens stored in HttpOnly cookies (XSS protection)
    • Access tokens used in Authorization headers
  • Stateless API design
    • No server-side session storage
    • Token validation on each request
    • Token introspection for permission checks
  • Token management
    • Automatic token refresh via Nuxt middleware
    • Token revocation on logout
    • Immediate invalidation when account status changes
  • Role-based access control
    • User roles: administrator, organiser, sponsor
    • Permission scopes for third-party applications
    • Granular API endpoint protection using NestJS Guards
  • Security measures
    • Rate limiting on authentication endpoints using @nestjs/throttler
    • Progressive delays after failed login attempts
    • Temporary account lockout after excessive failures
    • Audit logging of all authentication events

Data Protection

  • SSL/TLS encryption
  • Database encryption
  • File encryption
  • Secure headers
  • DDoS protection

Integration Points

External Services

  • Stripe

    • Payment processing using hosted Checkout

  • Nimlogix API

    • Stand design integration
    • Artwork requirements
    • Artwork review and approval/rejection

Development Approach

Code Organisation

  • Domain-driven design within monolithic structure
    • Clear separation of business domains (events, stands, artwork, payments)
    • Domain-specific models, services, and controllers
    • Shared infrastructure and utilities
  • Type definitions
  • API client generation
    • Swagger/OpenAPI documentation auto-generated by NestJS
    • TypeScript SDK auto-generated for frontend using Orval
    • Type-safe API calls with full IntelliSense support
    • Automatic synchronization between backend and frontend types
  • Automated testing

Deployment Strategy

  • Continuous integration
  • Automated testing
  • Environment-based deployments
    • Development environment for active development
    • Staging environment for pre-production testing
    • Production environment with zero-downtime deployments
  • Environment-specific configuration
  • Monitoring and logging

Performance Considerations

  • Caching strategy
  • Database optimisation
  • CDN integration
  • Load balancing
  • Background job processing

Monitoring and Observability

  • Application monitoring
  • Error tracking
  • Performance metrics
  • Database monitoring
  • Alert management

Future-Proofing

  • Domain-driven design implementation
    • Business domains (events, stands, artwork, payments) as separate modules within the monolithic application
    • Clear boundaries between domains using interfaces and service classes
    • Domain-specific models and repositories
    • Shared infrastructure for cross-domain concerns
    • Preparation for potential future service extraction
  • API versioning
    • Versioned API routes (e.g., /api/v1/stands, /api/v2/stands)
    • Backward compatibility for existing clients
    • Deprecation strategy for old versions
  • Extensible architecture
    • Service interfaces for external integrations
    • Event-driven architecture for domain communication
    • Plugin system for extending functionality
  • Scalable infrastructure
    • Horizontal scaling of application servers
    • Database read replicas
    • Caching strategy
  • Maintainable codebase
    • Comprehensive documentation
    • Automated testing
    • Code quality tools
    • Regular dependency updates

For detailed API specifications, see the API Documentation. For database schema details, refer to the Database Schema.