This is an example of implementing a microservice architecture based on Java technologies. The purpose is to show how I would handle different kinds of communications for microservices, looking for better performance and the perfect tools depending on the context.

This is not a product or application in itself; it is just a showcase of how Spring technologies could be implemented.

Api Gateway: It's the unique entry point for all users to the system. Use Spring Gateway to redirect all requests to the necessary microservice.

Common: Consist of different classes and services necessary for many microservices. It's used to avoid code duplication and can be imported as a dependency from any microservice.

Customer: Handle all customer and payment method information.

Docs: Contains all documentation and images used for any Design Doc.

Email Notification: Dedicated to all user's notification trough email. It isn't connected to API Gateway and use Kafka to communicate with other microservices.

Eureka Server: Use Spring Cloud Netflix Eureka to act like a discovery service and register all running microservice.

Loyalty: Handle all benefits for frequent customers.

Product: Handle product inventory classified by categories.

Security: Handle all service to create and validate JWT tokens, users, roles and permissions.

Shopping: Perform basic services for shopping modules like purchase.

Each purchase needs to handle product inventory, loyalty points and email notifications. So, it's necessary to use Grpc and Kafka to microservices interactions from a new microservice called Shopping.

The goals for this feature are:

Add a new microservice Shopping.

Use grpc and kafka for microservices communication.

Validate inventory and lot points.

Send email notification.

I've been implemented Spring Security and JWT to handle login workflow and validate access to public and private resources.

The goals for this feature are:

Handle access token with limited time to be used.

Handle refresh token flow.

Add authentication and authorization filters.