How the Go Module Proxy Works (GOPROXY)

GOPROXY is an environment variable that defines the list of servers the Go tool uses to download module dependencies, trying them in order until one succeeds. By default, it uses https://proxy.golang.org,direct, which fetches from the public proxy first and falls back to direct repository access if the proxy fails or is unavailable. You can change this list to use a private proxy or disable the public proxy entirely by setting the variable before running your Go commands.

export GOPROXY=https://your-private-proxy.example.com,direct
go get example.com/module@v1.0.0

GOPROXY tells Go where to look for external code libraries when you build your project. It works like a list of backup stores: Go checks the first one, and if it's empty or down, it tries the next one. This ensures your builds keep working even if the main public server is slow or blocked.