Notification Service

Microservice for sending notifications via email with RabbitMQ event consumption and retry mechanisms.

Tech Stack

Tech Stack

Category	Technology
Runtime	Node.js 24 LTS
Language	TypeScript
Framework	Express.js
Email	Nodemailer
Messaging	RabbitMQ
Validation	Joi
Testing	Jest + Supertest

Ports

Service	Port
HTTP API	3003

Quick Start

Docker (Recommended)

docker-compose up -d

Local Development

# Install dependencies
pnpm install

# Start dev server
pnpm dev:local

API Endpoints

REST API

Method	Endpoint	Description
GET	/api/v1/health	Health check
POST	/api/v1/test-email	Send test email

Events Consumed

Event	Source	Action
task.assigned	Task Service	Send assignment email
user.created	User Service	Send welcome email
project.member.added	Project Service	Send invite email

Environment Variables

# Server
NODE_ENV=development
PORT=3003
SERVICE_NAME=notification-service

# RabbitMQ
RABBITMQ_URL=amqp://admin:admin123@localhost:5672

# Email (SMTP)
SMTP_HOST=smtp.gmail.com
SMTP_PORT=587
SMTP_SECURE=false
SMTP_USER=your-email@gmail.com
SMTP_PASSWORD=your-app-password
EMAIL_FROM=noreply@example.com
EMAIL_FROM_NAME=Task Management System

Project Structure

src/
├── config/           # Configuration
├── controllers/      # HTTP handlers
├── services/         # Business logic (email, notification, failureTracking)
├── routes/           # API routes
├── validations/      # Joi schemas
├── messaging/        # RabbitMQ EventBus
├── middlewares/      # Express middleware
├── utils/            # Utilities (logger, ApiError, catchAsync, retry)
└── __tests__/        # Tests (unit + integration)

Scripts

Command	Description
pnpm dev	Start with Docker
pnpm dev:local	Start locally with hot reload
pnpm build	Build TypeScript
pnpm start	Start production
pnpm test	Run tests
pnpm lint	Lint code

Features

Retry Mechanism

Failed email deliveries are automatically retried with exponential backoff:

• Max retries: 3
• Backoff: 1s, 2s, 4s

Failure Tracking

Failed notifications are tracked and can be monitored for:

• Bounce detection
• Rate limiting
• Error patterns

Testing

# Run all tests
pnpm test

# With coverage
pnpm test:coverage

# Watch mode
pnpm test:watch

License

ISC