Understanding Back-End Project Structures in Go: A Guide to Separate Concerns

Code on laptop with hands typing in the dark Free Photo When I first started writing Go to make a back-end API, I did what most people do — threw everything into one file. The handler, the business logic, the database calls, all of it crammed together. It worked, until it didn't. The moment I tried to refactor or write tests, three things broke. Sound familiar? The fix isn't complicated, but it does require a bit of upfront thinking about how you organize your code. In this article I'll walk through a project structure that I learned recently. Companies like Uber and Netflix use similar patterns to manage large systems. It allows for scaling while remaining resilient to failures. Why Bother Separating Concerns? Most developers have all written messy code at some point. But once things are separated, the breathing room allows for testing, changes and reuse. The idea behind separation of concerns is simple: each part of your code should have one job and one job only. When your handler is