Continue the story about system architecture and describe the request flow.

The system architecture uses a microservices approach. Each service is responsible for its own business logic and interacts with others via REST API or gRPC.

The request flow usually starts with an API Gateway, which receives external requests and routes them to the appropriate microservice. For example, a request to retrieve user data passes through authentication, then the API Gateway directs the request to the User Service, which accesses the database and returns the result. If data from other services is needed, the User Service can make internal calls to other microservices.

An example of a simplified flow:

1. Client -> API Gateway
2. API Gateway -> User Service
3. User Service -> Database
4. User Service -> Order Service (if needed)
5. The response is returned back through the chain to the client

This approach allows for scaling individual components and simplifies maintenance.