brodygaudel/bank

1. This repository is a microservices monorepo. Each service is a separate Spring Boot application with its own Maven build, tests, and runtime configuration, so the architecture is deployment-unit oriented rather than a single shared application.

2. The edge layer is split into a discovery service and a reactive gateway. The discovery service is a Eureka registry; the gateway is the public entry point that routes requests to downstream services by service name, letting clients avoid talking to services directly.

3. The authentication service owns user identity and authorization. It models users, roles, and verification records, exposes REST endpoints for login and account/password management, and uses JWT-based security. Other services share the same JWT validation pattern through their own security filters/configs.

4. The customer service is a conventional CRUD service for customer master data. It persists a Customer entity through JPA, exposes REST endpoints, enforces domain validation such as minimum age, and returns DTOs for create/read flows. Other services consult it for customer existence and profile-related checks.

5. The account service is the most architecturally specialized part of the system. It implements CQRS and event sourcing with Axon Framework: command handling is separated from query handling, and account changes are emitted as domain events instead of being written directly to a single mutable model.

6. Inside the account service, the command side centers on an AccountAggregate plus command objects for create, activate, suspend, credit, debit, delete, and transfer. Commands pass through validation/interception, then the aggregate produces events such as AccountCreatedEvent or AccountDebitedEvent.

7. The account service query side builds a separate read model. Event handlers project account and operation events into JPA entities and repositories, and query handlers serve read requests from these materialized views. This means writes and reads are intentionally decoupled and can evolve independently.

8. Service-to-service communication is synchronous and client-based. The account and authentication services include REST clients for customer and notification interactions, so flows like “validate customer”, “send notification”, or “check account state” cross service boundaries through HTTP rather than shared database access.

9. The notification service is a dedicated outbound communication service. It accepts notification requests, renders email content using an HTML template, and centralizes messaging concerns so business services do not embed mail delivery logic.

10. Data ownership is service-scoped. Authentication manages users/roles/verifications, customer manages customers, account maintains both event-sourced command state and read-side projections, and notification is focused on delivery. Axon Server must be up first for the account service, while Docker support and the root Maven build indicate the repo is designed for containerized, independently runnable services.