📘 MiniEdu Microservices – Backend Architecture Overview

MiniEdu is a modular, backend-focused microservices-based educational platform designed for scalability, security, and asynchronous communication.

• Docker – Containerization of microservices
• Kubernetes – Container orchestration and scaling
• AWS (planned) – Cloud hosting, S3 for media storage, SES for email delivery
• Redis – Distributed caching for tokens/sessions
• Apache Kafka – Asynchronous event-driven communication
• PostgreSQL – Relational database for persistent storage

• Java 17 – Primary language for microservices
• Spring Boot – Base framework for each microservice
• Spring Security – Secure access control using JWT
• gRPC – Fast inter-service communication
• Custom Security SDK – Shared JWT generation and validation
• Lombok & Java Records – Reduce boilerplate and ensure immutability

Handles:

• User registration
• Login
• Email verification (via isActive flag)
• JWT generation using Security SDK

Responsibilities:

• Password hashing
• Stores user details in PostgreSQL
• Sends UserRegisteredEvent to Kafka for triggering verification emails

Endpoints:

• POST /register
• POST /login
• GET /verify?token=...

Provides:

• generateToken(userDetails) – For issuing JWTs during login
• validateToken(token) – For authenticating API requests

Used by:

• User Microservice
• Enrollment Microservice
• Course Microservice

Integrated directly as a dependency in each service.

Handles:

• Sending verification emails upon user registration

Responsibilities:

• Listens to UserRegisteredEvent from Kafka
• Sends emails using SMTP or AWS SES
• Generates email verification links

Communication:

• Kafka subscriber
• Optional REST endpoint for internal testing

Handles:

• Enrolling users into available courses

Responsibilities:

• Validates JWT using Security SDK
• Stores user-course relationships
• May emit enrollment events for analytics

Endpoints:

• POST /enroll
• GET /my-enrollments

Handles:

• Managing and serving course metadata and materials

Responsibilities:

• CRUD operations for courses
• Streams content (PDFs, videos, etc.)
• Validates JWT before granting access

Endpoints:

• POST /courses
• GET /courses/:id
• GET /courses

• Occurs after successful login or registration
• Generated via Security SDK using user details

• Included in Authorization: Bearer <token> header
• Validated inside each microservice using Security SDK

Security SDK ensures:

• Token signature integrity
• Expiration and issuer validation

• Validates and stores user
• Sets isActive = false
• Emits UserRegisteredEvent to Kafka

• Generates a secure verification link
• Sends email to the user

• Verifies token from the link
• Sets isActive = true