Internal packages

Context

An internal/ directory is a special convention. Code inside internal/ can only be imported by other code inside the same module (or its parent directories). This enforces encapsulation and prevents external usage of internal implementation details.

Example

Project structure with an internal package.

Code example

myproject/
├── go.mod
├── internal/
│   └── helper/
│       └── helper.go   // package helper
└── cmd/
    └── myapp/
        └── main.go      // can import internal/helper

// internal/helper/helper.go
package helper

func Help() string {
    return "internal help"
}

// cmd/myapp/main.go
package main

import (
    "fmt"
    "myproject/internal/helper"
)

func main() {
    fmt.Println(helper.Help())
}

Output

internal help

Useful links

• Go internal packages design
• Internal packages documentation