Backend Architecture Map of Content

🎯 Overview

Central hub for all backend architecture documentation, API references, and technical implementation guides across Nimbly Compass. This MOC provides developers and architects with comprehensive access to backend system design, patterns, and best practices.

Quick Start

• New to the backend? Start with Architecture Overview
• API Development? Jump to API Documentation
• Database Design? Check Database Architecture
• Performance Issues? Visit Performance Optimization

🏗️ System Architecture

High-Level Architecture

graph TB
    A[Client Applications] --> B[API Gateway]
    B --> C[Load Balancer]
    C --> D[Application Servers]
    
    D --> E[Authentication Service]
    D --> F[Core Services]
    D --> G[Integration Services]
    
    F --> H[(MongoDB)]
    F --> I[(Redis Cache)]
    F --> J[File Storage]
    
    G --> K[External APIs]
    G --> L[Webhooks]
    
    style B fill:#f9f,stroke:#333,stroke-width:2px
    style F fill:#bbf,stroke:#333,stroke-width:2px

Technology Stack

• Runtime: Node.js (v16+)
• Framework: Express.js
• Database: MongoDB (v5+)
• Cache: Redis
• Queue: RabbitMQ
• Storage: AWS S3 / Cloud Storage
• Monitoring: Prometheus + Grafana

📡 API Documentation

Core APIs

Service-oriented architecture with RESTful APIs:

Feature APIs

• 👥 Users API - /api/v2/users
• 📍 Sites API - /api/v2/sites
• 🔍 Issues API - /api/v2/issues
• 📊 Reports API - /api/v2/reports
• 📈 Dashboard API - /api/v2/dashboard

System APIs

• Authentication API - /api/v2/auth
• Permissions API - /api/v2/permissions
• Notifications API - /api/v2/notifications
• Files API - /api/v2/files
• Analytics API - /api/v2/analytics

API Standards

// Standard Response Format
{
  success: boolean,
  data: object | array,
  meta: {
    pagination: {...},
    timestamp: ISO8601,
    version: "2.0"
  },
  error: {
    code: string,
    message: string,
    details: object
  }
}

Authentication & Security

• JWT-based authentication
• OAuth2 integration support
• API key management
• Rate limiting
• CORS configuration
• Request validation

🗄️ Database Architecture

MongoDB Schema Design

Collections Overview

// Core Collections
- users
- organizations
- sites
- departments
- roles
- permissions
 
// Feature Collections
- issues
- audits
- reports
- questionnaires
- notifications
 
// System Collections
- sessions
- audit_logs
- api_keys
- webhooks

Schema Patterns

• Embedded Documents Pattern
• Reference Pattern
• Subset Pattern
• Computed Pattern
• Tree Structure Pattern

Indexing Strategy

// Performance Indexes
db.users.createIndex({ email: 1 }, { unique: true })
db.users.createIndex({ organizationId: 1, status: 1 })
db.issues.createIndex({ siteId: 1, status: 1, createdAt: -1 })
db.audits.createIndex({ "location": "2dsphere" })

🔧 Core Services

Service Architecture

Authentication Service

class AuthService {
  // Core methods
  login(credentials)
  logout(token)
  refresh(refreshToken)
  verify(token)
  generateTokens(user)
  validatePermissions(user, resource, action)
}

Notification Service

• Email notifications (SendGrid/SES)
• Push notifications (FCM)
• In-app notifications
• SMS notifications (Twilio)
• Webhook notifications

File Service

• Upload handling
• Image processing
• Document storage
• CDN integration
• Access control

🚀 Performance Optimization

Caching Strategy

Redis Implementation

// Cache Layers
1. API Response Cache (5-60 min)
2. Database Query Cache (1-5 min)
3. Session Store (24 hours)
4. Rate Limiting (sliding window)
5. Real-time data (pub/sub)

Query Optimization

• Aggregation pipelines
• Projection optimization
• Index utilization
• Query profiling
• Connection pooling

Scaling Patterns

• Horizontal scaling
• Load balancing
• Database sharding
• Microservices migration
• Event-driven architecture

🔄 Integration Patterns

Event-Driven Architecture

graph LR
    A[Event Producer] --> B[Message Queue]
    B --> C[Event Consumer 1]
    B --> D[Event Consumer 2]
    B --> E[Event Consumer 3]
    
    C --> F[Update Cache]
    D --> G[Send Notification]
    E --> H[Update Analytics]
    
    style B fill:#f9f,stroke:#333,stroke-width:2px

Common Events

// Event Types
'user.created'
'user.updated'
'issue.created'
'issue.resolved'
'audit.completed'
'report.generated'

External Integrations

• REST API clients
• Webhook handlers
• OAuth providers
• Payment gateways
• Analytics services
• Cloud storage

🛡️ Security Architecture

Security Layers

1. Network Security

   • SSL/TLS encryption
   • VPC configuration
   • Firewall rules
   • DDoS protection

2. Application Security

   • Input validation
   • SQL injection prevention
   • XSS protection
   • CSRF tokens

3. Data Security

   • Encryption at rest
   • Encryption in transit
   • PII handling
   • GDPR compliance

Authentication Flow

sequenceDiagram
    participant Client
    participant API
    participant Auth
    participant DB
    
    Client->>API: Login Request
    API->>Auth: Validate Credentials
    Auth->>DB: Check User
    DB-->>Auth: User Data
    Auth->>Auth: Generate JWT
    Auth-->>API: Tokens
    API-->>Client: Access + Refresh Token

📊 Monitoring & Logging

Monitoring Stack

• Metrics: Prometheus
• Visualization: Grafana
• Logs: ELK Stack
• APM: New Relic / DataDog
• Uptime: Pingdom
• Errors: Sentry

Key Metrics

# Application Metrics
- Request rate
- Response time
- Error rate
- Active users
- API usage
 
# System Metrics
- CPU usage
- Memory usage
- Disk I/O
- Network traffic
- Database connections

🔧 Development Practices

Code Organization

src/
├── controllers/     # Request handlers
├── services/       # Business logic
├── models/         # Data models
├── middleware/     # Express middleware
├── utils/          # Helper functions
├── config/         # Configuration
├── routes/         # API routes
└── tests/          # Test files

Testing Strategy

• Unit tests (Jest)
• Integration tests
• API tests (Supertest)
• Load tests (K6)
• Security tests

CI/CD Pipeline

graph LR
    A[Git Push] --> B[Build]
    B --> C[Test]
    C --> D[Security Scan]
    D --> E[Deploy Staging]
    E --> F[Integration Tests]
    F --> G[Deploy Production]
    
    style C fill:#f9f,stroke:#333,stroke-width:2px
    style G fill:#bbf,stroke:#333,stroke-width:2px

📚 Backend Resources

Documentation

• API Reference Guide
• Database Design Guide
• Security Best Practices
• Performance Tuning Guide
• Deployment Guide

Developer Tools

• Postman collections
• Swagger documentation
• Database migrations
• Seed data scripts
• Performance profilers

Code Examples

// Service Pattern Example
class IssueService extends BaseService {
  async createIssue(data, userId) {
    // Validate input
    const validated = await this.validate(data);
    
    // Apply business rules
    const processed = this.applyBusinessRules(validated);
    
    // Save to database
    const issue = await Issue.create(processed);
    
    // Emit event
    EventBus.emit('issue.created', { issue, userId });
    
    // Clear cache
    await Cache.invalidate(`issues:*`);
    
    return issue;
  }
}

🏷️ Related MOCs

• Frontend Architecture
• DevOps & Infrastructure
• Security Architecture
• Data Architecture

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📊 Backend Documentation Coverage

Component	Documentation	Status	Priority
API Reference	✅ Complete	Active	High
Database Schema	✅ Complete	Active	High
Service Architecture	⏳ In Progress	Draft	High
Security Guide	✅ Complete	Active	Critical
Performance Guide	⏳ In Progress	Draft	Medium
Integration Patterns	📝 Planned	-	Medium

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This MOC is maintained by the Backend Team. Last review: 2024-01-25 For questions or improvements, contact: Backend Team Lead