Stop Over-Engineering: A Pragmatic Approach to Microservices with Go

Microservices are often sold as the silver bullet for scaling. In reality, they are often a recipe for "distributed monolith" nightmares. If you are starting a new project, how do you build modular systems that don't crumble under the weight of their own complexity?

The Philosophy: Start with Modules, Not Services

Instead of splitting your code into separate repositories and network boundaries on day one, start with a modular monolith. This allows you to enforce boundaries while keeping the deployment lifecycle simple.

Structure Your Code for Future Growth

Use a clean architecture approach to ensure that your business logic is decoupled from your infrastructure. Here is a recommended directory structure:

/cmd           # Entry points for your application
/internal      # Private application code
  /user        # User domain logic
  /order       # Order domain logic
/pkg           # Public library code
/api           # API definitions (Protobuf/OpenAPI)

Implementation Example: Decoupled Domain Logic

In Go, you can use interfaces to ensure that your services don't depend on implementation details. This makes it trivial to split them into separate microservices later if necessary.

// internal/user/service.go
package user

type Repository interface {
    GetByID(id string) (*User, error)
}

type Service struct {
    repo Repository
}

func (s *Service) GetUser(id string) (*User, error) {
    return s.repo.GetByID(id)
}

Why this works

1. Low Friction: You can iterate fast without updating network contracts or handling partial failures.
2. Easy Refactoring: Because your domains are separated by Go packages (not network calls), refactoring is as simple as moving a folder.
3. Deployment Ready: When the time comes to scale, you can extract a package into a standalone binary in an afternoon because your dependencies are already explicitly defined via interfaces.

Final Thoughts

Don't build a microservice architecture before you have a service worth micro-sizing. Build for modularity first, and scale your infrastructure only when the business requirements demand it.