MERN Authentication Microservice

AuthWatch Secure. Scalable. Observable.

A robust authentication microservice for modern web applications, featuring JWT, email verification, password reset, and monitoring.

Features • Tech Stack • Getting Started • Architecture • Contributing

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📋 Overview

MERN Auth Microservice is a production-ready authentication backend for web and mobile apps. It provides secure user registration, login, JWT-based sessions, email verification, password reset, and exposes metrics for monitoring. Built with Node.js, Express, and MongoDB, it includes comprehensive test coverage with Jest and Supertest, and is containerized for easy deployment.

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📸 Screenshots

API Documentation Interactive Swagger UI for all endpoints
Prometheus & Grafana Dashboards Real-time monitoring endpoint	Authentication Flow JWT, Email Verification, Password Reset, Monitoring

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🌟 Features

Authentication

• JWT-based Login — Secure, stateless sessions
• User Registration — With hashed passwords
• Email Verification — OTP-based, with expiry
• Password Reset — Multi-step, OTP-protected
• Logout — Secure session termination

Security

• HTTP-only Cookies — Prevent XSS attacks
• Bcrypt Password Hashing — 10 salt rounds
• Environment-based Cookie Security — SameSite, Secure flags
• Input Validation — Required fields, email normalization

Monitoring & Observability

• Prometheus Metrics — System and custom HTTP request metrics
• Grafana Ready — For dashboard visualization

Testing

• Jest Test Suite — Comprehensive unit and integration tests
• Supertest — HTTP API endpoint testing
• MongoDB Memory Server — In-memory database for testing
• Test Coverage — Authentication flows and endpoints

Developer Experience

• Dockerized — Easy deployment anywhere
• Modular Codebase — Clean separation of concerns

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🎯 Use Cases

• User Authentication Service for any web/mobile app
• Microservice in a larger architecture
• API Gateway Auth Layer
• Production-ready Auth for SaaS
• Learning/Reference for secure Node.js auth

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🛠 Tech Stack

Backend

Technology	Purpose
Express.js	Backend Framework
MongoDB	NoSQL database
Mongoose	MongoDB ODM
JWT	Token-based authentication
bcryptjs	Password hashing
Nodemailer	Email sending (SMTP)
prom-client	Prometheus metrics

Testing

Technology	Purpose
Jest	Testing framework
Supertest	HTTP assertion library
MongoDB Memory Server	In-memory MongoDB for testing

DevOps

Technology	Purpose
Docker	Containerization
Prometheus	Monitoring
Grafana	Metrics visualization

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🏗 Architecture

┌──────────────────────────────────────────────┐
│                Client (Frontend)             │
│      (Any web/mobile app, Postman, etc.)     │
└──────────────────────────────────────────────┘
								│      HTTPS/REST
								▼
┌──────────────────────────────────────────────┐
│        MERN Auth Microservice (Node.js)      │
│ ┌──────────────┐  ┌──────────────┐           │
│ │  Express.js  │  │  Prometheus  │           │
│ │  API Server  │  │  Metrics     │           │
│ └──────────────┘  └──────────────┘           │
│        │                │                    │
│        ▼                ▼                    │
│   MongoDB Atlas   /metrics endpoint          │
└──────────────────────────────────────────────┘

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🚀 Getting Started

Prerequisites

• Node.js (v18 or higher)
• npm
• MongoDB (local or Atlas)

Installation

1. Clone the repository

   git clone https://github.com/karanhimadri/mern-authentication-microservice.git
   cd mern-authentication-microservice/server

2. Install dependencies

   npm install

3. Configure environment variables

   • Copy .env.example to .env and fill in your values:

     MONGO_URI=your_mongodb_connection_string
     JWT_SECRET=your_jwt_secret
     SMTP_USER=your_smtp_user
     SMTP_PASS=your_smtp_pass
     SENDER_EMAIL=your_email@example.com
     NODE_ENV=development
     PORT=4000

Running the Application

npm start
# Server runs on http://localhost:4000

Testing

Run the test suite to ensure everything is working correctly:

npm test
# Runs all tests with Jest

The test suite includes:

• Unit Tests: Authentication controller functions
• Integration Tests: API endpoint testing with Supertest
• Mocked Services: Email service, JWT, and database operations

Test files are located in the /test directory:

• auth.test.js - Authentication endpoint tests
• app.test.js - Application setup tests

Docker

docker build -t mern-auth-microservice .
docker run -p 8080:4000 --env-file .env mern-auth-microservice
# App will be available at http://localhost:8080

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👨‍💻 Developer Profile

Himadri Karan
Backend Developer & Business Solutions Specialist

• 📧 Email: Karanhimadri1234@gmail.com
• 💼 LinkedIn: linkedin.com/in/himadrikaran
• 🌐 Portfolio: Himadri.me
• 🐙 GitHub: github.com/karanhimadri

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Made with ❤️ and lots of ☕

If you found this project helpful, please give it a ⭐️!