# Architecture Decision Record for Payment Boundary

## Context
In the context of our ongoing project, we are focused on defining clear boundaries for the payment services. This is crucial to ensure that our architecture remains clean, modular, and maintainable. We need to outline the responsibilities and interactions of various components involved in payment processing.

## Decision
To establish a clear payment boundary, we will:
1. Define the payment service as a separate module.
2. Use REST APIs for communication between the payment service and other microservices.
3. Ensure that any sensitive operations, like payment processing, are encapsulated within the payment service and not exposed directly to clients.
4. Implement service-level security to protect payment information.

## Alternatives
- **Monolithic Approach**: Keeping all payment processing logic within a single application. This is easier to manage initially but leads to tight coupling.
- **Event-Driven Architecture**: Using a messaging system for inter-service communication. This would add complexity in terms of managing events and message reliability, but would result in a more decoupled system.

## Consequences
By defining clear boundaries for payment processing:
- We achieve separation of concerns, which improves maintainability.
- We can independently scale the payment service based on demand.
- Security risks are minimized as sensitive operations are isolated.

This decision will guide the development and integration efforts moving forward, especially when considering transaction management and error handling.