Subscription Tracker API

A Node.js and Express.js-based REST API designed to manage user subscriptions, automate workflows, send email reminders, and enhance user experience with structured automation. The API is powered by MongoDB, secured using JWT authentication, and deployed using PM2 for efficient process management on an Azure Linux Server.

This API is designed for subscription-based businesses, workflow automation, and email reminder services. It ensures scalability, security, and performance in production environments.

---

📌 Key Features

✅ User Authentication & Authorization

• Secure login and registration with JWT-based authentication.
• Role-based access control (RBAC) for admin and users.

✅ Subscription Management

• Create, update, delete, and retrieve subscription details.
• Track subscription status (active, expired, cancelled).

✅ Automated Email Reminders

• Sends subscription renewal reminders via Nodemailer.
• Configurable reminder intervals (days before expiry).

✅ Workflow Automation

• Allows users to define custom workflows for actions like:
  • Automated subscription renewal.
  • Custom email notifications.
  • Trigger-based alerts.

✅ Error Handling Middleware

• Centralized error handling using Express middleware.

✅ MongoDB Integration with Mongoose

• Optimized data storage and schema validation.

✅ Logging & Debugging

• PM2 process management with real-time logging.

✅ Production-Ready Deployment

• Hosted on Azure Linux VM with port 3000 open.

---

📂 Project Structure

Subscription-API/
│── config/
│   ├── database.js          # MongoDB connection setup  
│── middleware/
│   ├── auth.middleware.js   # Authentication middleware  
│   ├── error.middleware.js  # Global error handling  
│   ├── arcjet.middleware.js # Custom middleware for additional processing  
│── models/
│   ├── user.model.js        # Mongoose schema for users  
│   ├── subscription.model.js # Subscription schema  
│   ├── workflow.model.js    # Workflow schema  
│── routes/
│   ├── auth.routes.js       # Routes for authentication  
│   ├── user.routes.js       # Routes for user management  
│   ├── subs.routes.js       # Routes for subscription management  
│   ├── workflow.routes.js   # Routes for workflows  
│── controllers/
│   ├── auth.controller.js   # Handles authentication logic  
│   ├── user.controller.js   # Handles user-related operations  
│   ├── subs.controller.js   # Handles subscription-related operations  
│   ├── email.controller.js  # Handles email reminder services  
│── utils/
│   ├── emailSender.js       # Email sending logic (Nodemailer)  
│   ├── responseHandler.js   # Utility function for API responses  
│── scripts/
│   ├── reminderWorker.js    # Cron job for scheduled reminders  
│── .env.example             # Environment variables sample  
│── index.js                 # Main server file  
│── package.json             # Project dependencies  
│── README.md                # Project documentation  

---

📧 Automated Email Reminders

The API uses Nodemailer to send automated email reminders for upcoming subscription renewals.

How It Works:

1. A cron job runs every 24 hours to check for subscriptions nearing expiration.
2. If a subscription is set to expire within the configured reminder period, an email is sent to the user.
3. The reminder email includes subscription details and a link to renew the subscription.

Configurable Reminder Settings

• Default reminder: 7 days before expiration.
• Users can customize reminder intervals via API.

Example Email Template

Subject: Subscription Expiry Reminder - Action Required

Hello [User Name],

Your subscription to [Service Name] is set to expire on [Expiry Date].

To continue enjoying uninterrupted service, please renew your subscription at:

[Renewal Link]

Thank you for choosing us!

Best Regards,  
Subscription Tracker Team

---

🔄 Workflow Automation

This API allows users to create custom workflows that automate repetitive tasks like:

✅ Subscription Renewal Automation

• Auto-renews a subscription when the expiry date is reached.

✅ Custom Email Notifications

• Sends emails for successful renewals, failed payments, etc.

✅ Trigger-Based Alerts

• Users can define custom triggers (e.g., notify admin on new user registration).

Example Workflow Request (JSON)

{
  "name": "Auto-renewal Workflow",
  "trigger": "subscription_expiring",
  "action": "renew_subscription",
  "parameters": {
    "days_before": 3
  }
}

Workflow Execution Process:

1. A trigger event (e.g., subscription expiry) is detected.
2. The corresponding workflow action is executed automatically.
3. The user is notified about the action via email or API response.

---

🖥️ Deployment on Azure VPS

Step 1: Install Node.js & PM2 on VPS

curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt install -y nodejs
npm install -g pm2

Step 2: Allow Port 3000 on Azure Firewall

Ensure your Azure Network Security Group (NSG) allows inbound traffic on port 3000:

1. Go to Azure Portal → Virtual Machines → Your VM → Networking.
2. Click "Add inbound port rule" and enter:
   • Port: 3000
   • Protocol: TCP
   • Action: Allow
3. Click "Save" and apply changes.

Step 3: Start API using PM2

pm2 start index.js --name subscription-api
pm2 save
pm2 startup

Step 4: Restart PM2 & Check Logs

pm2 restart subscription-api
pm2 logs subscription-api

---

📌 API Endpoints

🔐 Authentication

Method	Endpoint	Description
POST	/api/v1/auth/sign-up	Register a new user
POST	/api/v1/auth/sign-in	User login (JWT)

👤 User Management

Method	Endpoint	Description
GET	/api/v1/users	Get all users
GET	/api/v1/users/:id	Get user by ID

📄 Subscription Management

Method	Endpoint	Description
POST	/api/v1/subscriptions	Create a new subscription
GET	/api/v1/subscriptions	Get all subscriptions

🔄 Workflow Automation

Method	Endpoint	Description
POST	/api/v1/workflows	Create a workflow
GET	/api/v1/workflows	Get all workflows

---

🚀 Future Plans

🔹 Multi-Tier Subscription Plans (Basic, Premium, Enterprise)
🔹 Payment Gateway Integration (Stripe, Razorpay, PayPal)
🔹 AI-Powered Predictive Analytics for subscription trends
🔹 GraphQL Support for efficient data retrieval
🔹 Microservices Architecture for better scalability
🔹 Mobile App API Integration for native applications

---

Environment Variables (.env)

PORT=3000
SERVER_URL="http://localhost:3000"
#kiji
NODE_ENV='development'

DB_URI=""

JWT_SECRET=""
JWT_EXPIRES_IN="7d"

ARCJET_KEY=""
ARCJET_ENV="Development"


#upstash

QSTASH_URL=
QSTASH_TOKEN=""
QSTASH_CURRENT_SIGNING_KEY=""
QSTASH_NEXT_SIGNING_KEY=""


#nodemailer

EMAIL_PASSWORD=""

---

📜 License

This project is licensed under the MIT License.

---