As of Go 1.13, Go Modules are the standard. Modules leverages both the Go proxy and Checksum Database for efficiently and securely fetching packages.
There is a Go environment variable called GOPROXY that you can check out on your environment using the command go env. This environment variable tells Go where to download modules from. Often times it is a comma separated list that ends in direct. Something like GOPROXY="https://proxy.golang.org,direct" is standard. This tells Go to reach out to https://proxy.golang.org for all modules first and if it can't find them there, then go straight to the VCS system (direct). **One caveat to the proxy is that all modules must be publicly accessible. This is not the case **