🎯 Design Overview

🛠️ System Design Definition

System Overview:
A subscription management platform enabling users to extend EMI payment dates by paying a minimal charge. The platform is built using a microservices architecture that facilitates independent operation, resilience, and scalability.

Microservices:

1. User Service
   - Endpoint: /register
   - Database: users
   - RabbitMQ: Publishes to subscription_user_registration_queue and payment_user_registration_queue

   - Endpoint: /login, /profile
   - Database: users

2. Payment Service
   - Database: payment.users, payments
   - RabbitMQ:
     - Consumes user details from payment_user_registration_queue
     - Consumes payment details from subcription_queue
     - Publishes to notification_queue

3. Notification Service
   - RabbitMQ: Consumes from notification_queue
   - External: Email Service

4. Subscription Service
   - Endpoint: 
     - Create a subscription: POST /
     - Extend subscription due date: POST /:subscriptionId/extend
     - Get extension charges: POST /:subscriptionId/extensionCharges
     - Retrieve payment history for a subscription: GET /user/paymentHistory/:userId
     - Get all subscriptions for a user: GET /user/:userId
     - Update subscription status: PUT /:subscriptionId
     - Cancel a subscription: DELETE /:subscriptionId/cancel
   - RabbitMQ:
     - Publishes to payment_queue
     - Publishes to notification_queue
     - Consumes from payment_user_registration_queue

5. RabbitMQ
   - Queue: subscription_user_registration_queue
   - Queue: payment_user_registration_queue
   - Queue: payment_queue
   - Queue: notification_queue
   - Queue: update_payment_queue

6. Databases
   - User Service Database: users
   - Payment Service Database: payment.users, payments
   - Subcription Service Database: subscriptions, subscription.users, subscription.payments
   - Notification Service Database: notifications

🔄 Data Flow

1. User Registration:

   • The user registers via the User Service.
   • The User Service creates a user entry in the users database within its own microservice.
   • The User Service then publishes user data to two separate queues: subscription_user_registration_queue and payment_user_registration_queue.
   • The Subscription Service and Payment Service consume these messages to create entries in their respective subscriptionusers and paymentusers collections.

2. Subscription Management:

   • The user creates a subscription via the Subscription Service.
   • The Subscription Service handles the subscription creation based on the provided subscription type (e.g., one-time, 3-month, 6-month, 12-month).
   • It schedules payments by publishing messages to the payment_queue, which are then consumed by the Payment Service.
   • If the user chooses to extend a payment, the Subscription Service finds the nearest payment due date and publishes a message to the update_payment_queue to extend the payment date.
   • The Subscription Service also publishes relevant data to the notification_queue to inform the user of subscription creation or payment extensions.

3. Payment Processing:

   • The Payment Service consumes messages from the payment_queue (for scheduled payments) and update_payment_queue (for extended payments).
   • The Payment Service retrieves user details from the paymentusers collection.
   • On the scheduled payment day, the Payment Service processes the payment using stored card details through the Stripe payment gateway.
   • Payment details, whether successful or failed, are stored in the payments collection.
   • Upon processing a payment (whether successful or failed), the Payment Service publishes a notification to the notification_queue.

4. Notification Dispatch:

   • The Notification Service consumes messages from the notification_queue.
   • It sends out emails to users through an external email service regarding their payment status, subscription creation, or reminders.
   • The service also manages reminders for failed payments, sending notifications every 2 hours, and sending minimum balance alerts one day prior to the payment date.

🔍 API Endpoints

🚀⚡ Project: payment-subscription-api

📁 Collection: user-service

🔑 Register User

• Endpoint: POST /api/users/register
• URL: http://localhost:3005/api/users/register
• Body:

  {
      "name": "Abhishek Kumar",
      "email": "abhishekumar1404@gmail.com",
      "password": "abhishek@123"
  }

🔑 Login User

• Endpoint: POST /api/users/login
• URL: http://localhost:3005/api/users/login
• Body:

  {
      "email": "abhishekumar1402@gmail.com",
      "password": "abhishek@123"
  }

👤 Get User Profile

• Endpoint: GET /api/users/profile
• URL: http://localhost:3005/api/users/profile?userId=66c43f3a24855c2357123a82
• Headers:
  • Authorization: Bearer <your_token>

🔓 Forgot Password

• Endpoint: POST /api/users/forgot-password
• URL: http://localhost:3005/api/users/forgot-password
• Body:

  {
      "email": "abhishekumar1406@gmail.com"
  }

🔐 Verify OTP

• Endpoint: POST /api/users/verify-otp
• URL: http://localhost:3005/api/users/verify-otp
• Body:

  {
      "email": "abhishekumar1406@gmail.com",
      "otp": "12345"
  }

🔑 Reset Password

• Endpoint: POST /api/users/reset-password
• URL: http://localhost:3005/api/users/reset-password
• Body:

  {
      "email": "abhishekumar1406@gmail.com",
      "newPassword": "abhishek@123"
  }

💳 Set Default Payment Method

• Endpoint: POST /api/users/set-default-payment-method
• URL: http://localhost:3005/api/users/set-default-payment-method
• Headers:
  • Authorization: Bearer <your_token>
• Body:

  {
      "paymentMethodId": "pm_1PpqhOSHpa4aOdjUqJwWQ5KS",
      "userId": "66c43f3a24855c2357123a82"
  }

💳 Get Payment Methods

• Endpoint: GET /api/users/payment-methods
• URL: http://localhost:3005/api/users/payment-methods?userId=66c43f3a24855c2357123a82
• Headers:
  • Authorization: Bearer <your_token>

💳 Delete Payment Method

• Endpoint: DELETE /api/users/payment-methods
• URL: http://localhost:3005/api/users/payment-methods?userId=66c43f3a24855c2357123a82
• Headers:
  • Authorization: Bearer <your_token>
• Body:

  {
      "paymentMethodId": "pm_1PprQ2SHpa4aOdjUS533gSgG"
  }

---

📁 Collection: Subscription Service

📅 Create Subscription

• Endpoint: POST /api/subscriptions
• URL: http://localhost:3004/api/subscriptions
• Body:

  {
      "userId": "66c402654422fb46a000dc72",
      "amount": 1799,
      "subscriptionType": "onetime"
  }

📅 Extend Subscription

• Endpoint: POST /api/subscriptions/:subscriptionId/extend
• URL: http://localhost:5004/api/subscriptions/66b020293bc2a6af4b67917d/extend
• Body:

  {
      "extendPaymentDays": 20
  }

💰 Get Extension Charges

• Endpoint: POST /api/subscriptions/:subscriptionId/extensionCharges
• URL: http://localhost:5004/api/subscriptions/66b020293bc2a6af4b67917d/extensionCharges
• Body:

  {
      "extendPaymentDays": 15
  }

📝 Get User Subscriptions

• Endpoint: GET /api/subscriptions/user/:userId
• URL: http://localhost:5004/api/subscriptions/user/66b01ffe883eebfca00e8ab3

📝 Get Payment History

• Endpoint: GET /api/subscriptions/user/paymentHistory/:userId
• URL: http://localhost:5004/api/subscriptions/user/paymentHistory/66b020293bc2a6af4b67917d

🔄 Update Subscription Status

• Endpoint: PUT /api/subscriptions/:subscriptionId
• URL: http://localhost:5004/api/subscriptions/66a1af96566e040a19105d72
• Body:

  {
      "status": "active"
  }