Answer
Common Web API design patterns improve maintainability, scalability, and testability:
- Repository Pattern – Abstracts data access; simplifies unit testing and business logic separation.
- Unit of Work – Groups operations under a single transaction for consistency.
- CQRS – Separates read and write operations for scalability and performance.
- Mediator / MediatR – Decouples request-handling logic using command/query handlers.
- Decorator Pattern – Adds logging, caching, or auditing without modifying core business logic.