Building Scalable REST API with CodeIgniter 4

Best practices for structuring a large-scale REST API using CodeIgniter 4, including service layers, repository pattern, and API versioning.

CodeIgniter 4 provides a solid foundation for building REST APIs. In this post, I'll share my experience structuring APIs that scale well and remain maintainable.

Service Layer Pattern

Instead of putting business logic in controllers, extract it into service classes. This keeps controllers thin and makes business logic testable.

Repository Pattern

Abstract database interactions behind repository interfaces. This makes it easy to switch data sources and mock in tests.

API Versioning

Use URL prefix versioning (/api/v1/, /api/v2/) to maintain backward compatibility.