# Payment Boundary Decision Record

## Context
In developing the architecture for the payment processing system, our objective is to ensure a clear separation between the application logic and the payment gateways. This boundary will help maintain a clean architecture and allow for easier testing and maintainability.

## Decision
We have decided to implement a port and adapter pattern where the payment gateway is accessed via a defined interface (port) rather than being directly referenced in the domain model. This ensures that our domain logic remains agnostic of the specific implementations of payment gateways.

## Alternatives
1. Direct coupling with the payment gateway: This approach could lead to tight coupling and hinder maintainability and testability.
2. Abstracting payment logic into a service layer: While this maintains separation, it increases complexity and could introduce overhead. 

## Consequences
- By adhering to the port and adapter pattern, we ensure our domain model remains clean and focused on business logic.
- Changes in payment gateway implementations can be managed without affecting the domain logic, leading to improved agility.