Structuring your Golang app: Flat structure vs. layered architecture

Structuring a Go application is crucial to its development, and the choice largely depends on the project's complexity and requirements. Go doesn't prescribe a specific structure, leaving developers to choose between a flat structure and a layered architecture. A flat structure, where all files reside in the same directory, is simple and suitable for libraries, simple scripts, or CLI applications, but can become unwieldy as complexity grows. In contrast, a layered architecture, which separates files based on functionality (models, controllers, views), is better suited for complex projects like REST APIs, offering clear separation of concerns and scalability. The article illustrates these concepts through a practical example of building a note-taking API, showing how a flat structure can be transformed into a layered one. It concludes that while a flat structure works for straightforward tasks, a layered approach is more appropriate for larger, more complex applications, with other advanced structures like domain-driven development or hexagonal architecture also being viable for scaling applications.