Go modules

Context

A Go module is a collection of related Go packages versioned together as a single unit. Modules replace the old GOPATH‑based workflow and provide:

Versioning – Semantic versions (v1.2.3) are enforced.
Dependency management – go.mod lists required modules and versions.
Reproducible builds – go.sum ensures integrity.

The module system was introduced in Go 1.11 and became the default in Go 1.16.

Core files

go.mod – Defines the module path (e.g., github.com/user/project) and its dependencies.
go.sum – Contains checksums of dependencies to verify integrity.

Basic commands

Command	Purpose
`go mod init <module>`	Create a new module in the current directory.
`go get <module>`	Add a dependency (or update it).
`go mod tidy`	Remove unused dependencies and add missing ones.
`go mod vendor`	Copy dependencies to a `vendor/` folder (optional).

Example

Create a new module named “hello”.

Code example

mkdir myproject
cd myproject
go mod init hello

Output

go: creating new go.mod: module hello

Now go.mod contains:

module hello

go 1.24

Adding a dependency

go get rsc.io/quote

This updates go.mod and downloads the module.