How to use custom packages in Golang?

I’m trying to create and use a custom package in Go. It’s probably something very obvious but I cannot find much information about this. Basically, I have these two files in the same folder:


package mylib

type SomeType struct {



package main

import (

func main() {


When I try to go run main.go , I get this error:

main.go:4:2: import "mylib": cannot find package

I’ve tried to run go build mylib.go first but it doesn’t seem to be doing anything (no file generated, no error message). So any idea how I could do this?

1 Like

First, be sure to read and understand the “How to write Go code” document.

The actual answer depends on the nature of your “custom package”.

If it’s intended to be of general use, consider employing the so-called “Github code layout”. Basically, you make your library a separate go get -table project.

If your library is for internal use, you could go like this:

  1. Place the directory with library files under the directory of your project.
  2. In the rest of your project, refer to the library using its path relative to the root of your workspace containing the project.

To demonstrate:


Now, in the top-level main.go , you could import "myproject/mylib" and it would work OK.