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Introduction

The backend of Comdeall is built using NestJS, a progressive Node.js framework designed for scalable and maintainable server-side applications. Comdeall is a comprehensive platform for child development and therapy management, serving as the backbone for assessment management, lesson planning, appointment scheduling, and therapist coordination across mobile and web platforms.

⚙️ Core Technologies & Tools​

CategoryStack / Tool
FrameworkNestJS (v11.x)
LanguageTypeScript
DatabasePostgreSQL with Hasura GraphQL engine
ORMPrisma for schema management
AuthenticationJWT + Firebase Admin SDK
Queue & JobsBullMQ + Redis
Monitoring & APMPrometheus, Grafana, Loki + Promtail
NotificationsFirebase Cloud Messaging (FCM) for push notifications
Payment ProcessingRazorpay integration + Appstore
Media & StorageAWS S3 + Cloudinary for file management
Realtime & EventsWebSockets (socket.io) + @nestjs/event-emitter
PDF GenerationPuppeteer for report generation

�� Authentication & Authorization​

  • JWT-based authentication with access/refresh token pattern
  • Firebase Admin SDK for user management and push notifications
  • Role-based access control (Parent, Therapist, Admin)
  • Social Login integration ready (Google, Facebook, Apple)
  • Sessionless API secured using token-based authentication

🧰 Development Scripts​

From the apps/backend directory, you can use the following scripts:

# Run dev server with watch mode
npm run start:dev

# Run e2e tests
npm run test:e2e

# Build the project
npm run build

# Spin up local Docker services (PostgreSQL, Redis, Hasura, etc.)
npm run local:up

# Database and Hasura setup
npm run hasura:setup
npm run prisma:setup

# Open development tools
npm run hasura:console    # Hasura GraphQL console
npm run prisma:studio     # Prisma Studio for database management

💡 The local:up script includes Prometheus configuration and starts all required services.

🗃️ Database & ORM​

  • PostgreSQL as the primary database
  • Hasura GraphQL engine for real-time GraphQL API
  • Prisma for:
    • Schema migrations and management
    • Type-safe database queries
    • Database introspection and studio access

Key database scripts:

npm run prisma:dbpull      # Pull schema changes from database
npm run prisma:generate    # Generate Prisma client
npm run prisma:studio      # Launch Prisma Studio
npm run hasura:console     # Open Hasura console
npm run hasura:migrate     # Apply Hasura migrations

📊 Monitoring & Observability​

  • Prometheus metrics collection via @willsoto/nestjs-prometheus
  • Grafana dashboards for metrics visualization
  • Loki + Promtail for centralized logging
  • Jaeger for distributed tracing
  • Winston for structured logging with daily rotation
  • OpenTelemetry integration for observability

🧩 Key Modules and Services​

Core Business Logic​

  • Assessment Management - Child development assessments and scoring
  • Lesson Plan System - Structured learning plans with progress tracking
  • Appointment Scheduling - Therapist-child appointment management
  • User Management - Parent, therapist, and admin user roles
  • Subscription Management - Plan-based access control
  • Payment Processing - Razorpay integration for subscriptions and appointments

Supporting Services​

  • Media Management - File uploads, storage, and retrieval
  • Notification System - Firebase push notifications
  • Background Jobs - Queue-based processing with BullMQ
  • Caching - Redis-based response caching
  • WebSocket Gateway - Real-time communication
  • Support System - Ticket management and resolution

📦 Testing & Code Quality​

  • Unit and E2E tests powered by jest
  • Code linting with ESLint + Prettier
  • TypeScript strict mode enabled
  • Comprehensive test coverage for business logic
npm run test
npm run test:watch
npm run test:coverage
npm run test:e2e

🚀 API & Documentation​

The backend exposes comprehensive APIs for:

  • RESTful endpoints with Swagger documentation
  • GraphQL API via Hasura for real-time queries
  • WebSocket connections for live updates
  • File upload/download endpoints
  • Authentication and authorization flows

Access Swagger documentation at: http://localhost:${PORT}/api

📄 Environment Setup​

Create .env file with required variables:

# Database
DATABASE_URL=postgresql://...
POSTGRES_HOST=localhost
POSTGRES_PORT=5432
POSTGRES_DB=comdeall
POSTGRES_USER=postgres
POSTGRES_PASSWORD=password

# Authentication
JWT_SECRET=...
FIREBASE_PROJECT_ID=...
FIREBASE_PRIVATE_KEY=...
FIREBASE_CLIENT_EMAIL=...

# External Services
RAZORPAY_KEY_ID=...
RAZORPAY_KEY_SECRET=...
SENDGRID_API_KEY=...

# Hasura
HASURA_GRAPHQL_ADMIN_SECRET=...
HASURA_GRAPHQL_ENDPOINT=http://localhost:8080/v1/graphql

# Monitoring
PROMETHEUS_PORT=9090
GRAFANA_PORT=3000
GRAFANA_ADMIN_PASSWORD=...

Refer to .env.example for the complete list of required environment variables.

🏗️ Architecture Highlights​

  • Modular Design - Clean separation of concerns with dedicated modules
  • GraphQL + REST - Hybrid API approach for optimal performance
  • Real-time Updates - WebSocket integration for live data
  • Background Processing - Queue-based job processing
  • Comprehensive Logging - Structured logging with multiple outputs
  • Health Checks - Built-in health monitoring endpoints
  • Rate Limiting - API protection with throttling
  • Caching Strategy - Multi-layer caching for performance

✅ Final Notes​

This backend is specifically designed for child development and therapy management, providing a robust foundation for:

  • Assessment tracking and progress monitoring
  • Lesson plan management with adaptive learning paths
  • Appointment coordination between therapists and families
  • Subscription-based access to premium features
  • Real-time communication and notifications
  • Comprehensive reporting and analytics

🚀 Built for scale. Ready for real-world child development applications. Let's explore the specific modules and their functionality.