📢 Distributed Notification and Alert System

📌 Overview

This project is a distributed backend system designed to process and deliver notifications across multiple channels (Email, SMS, Push). It supports real-time alerts, scheduled notifications, user preference handling, and query-driven delivery logic. The system is built for scalability, resilience, and extensibility, leveraging Node.js, Kafka, MongoDB, and Dockerized microservices.

---

🎯 Key Features

• Real‑Time & Scheduled Delivery: Immediate processing for urgent alerts, scheduled pipelines for deferred notifications.
• User Preferences: Configurable quiet hours, channel selection, and throttling limits.
• Advanced Query Logic:
  • Throttling to enforce per‑user limits.
  • Quiet Hours Filtering.
  • Deduplication of similar alerts.
  • Aggregation of low‑priority notifications.
  • Priority‑Based Delivery.
• Resilient Messaging: Kafka decouples ingestion, processing, and delivery for fault tolerance.
• Retry & Logging: Failed deliveries retried with logging into MongoDB.
• Analytics API: /analytics endpoint for delivery stats, retries, and engagement metrics.

---

🎯 Objectives

• Ingest and validate notification requests via APIs.
• Process notifications in real-time or schedule them for future delivery.
• Respect user preferences (quiet hours, channel selection, throttling limits).
• Support deduplication, aggregation, and prioritization of alerts.
• Deliver notifications reliably with retry logic and logging.
• Provide analytics and monitoring endpoints for system visibility.

---

⚙️ Implementation Details

• Backend Framework: Node.js, Express.js
• Messaging System: Apache Kafka
• Database: MongoDB (notifications, preferences, analytics)
• Job Scheduling: node-schedule
• ORM: Mongoose
• Containerization: Docker + Docker Compose

---

🏗️ System Components

1. Notification Ingestion & Validation Service

   • /notify API endpoint to receive requests.
   • Validates payload and publishes to Kafka topic notifications.

2. Notification Processing & Scheduling Engine

   • Real-time delivery for urgent/high-priority alerts.
   • Scheduled notifications stored in MongoDB and checked periodically.

3. User Preferences & Rules

   • Preferred channels (Email, SMS, Push).
   • Quiet hours (Do Not Disturb).
   • Notification limits (e.g., max 3/hour).

4. Query Logic

   • Throttling: Restrict notifications per user-defined limits.
   • Quiet Hours Filtering: Reschedule notifications outside quiet hours.
   • Deduplication: Suppress duplicate alerts within a time window.
   • Aggregation: Batch low-priority notifications into summaries.
   • Urgent Alerts: Immediate bypass of scheduling.

5. Notification Delivery Service

   • Channels: Email, SMS, Push (mock integrations).
   • Retry mechanism for failed deliveries.
   • Logging of statuses in MongoDB.

6. Analytics & Monitoring

   • /analytics endpoint for delivery stats, retries, and engagement metrics.

---

🛠️ Installation & Setup

# Clone the repository
git clone https://github.com/akshay931/distri_notification_and_alert_system.git
cd distri_notification_and_alert_system

# Install dependencies
npm install

# Start services with Docker Compose
docker-compose up -d