Configuration for downloading non-public code ¶
The go command defaults to downloading modules from the public Go module mirror at proxy.golang.org. It also defaults to validating downloaded modules, regardless of source, against the public Go checksum database at sum.golang.org. These defaults work well for publicly available source code.

The GOPRIVATE environment variable controls which modules the go command considers to be private (not available publicly) and should therefore not use the proxy or checksum database. The variable is a comma-separated list of glob patterns (in the syntax of Go's path.Match) of module path prefixes. For example,

GOPRIVATE=*.corp.example.com,rsc.io/private
causes the go command to treat as private any module with a path prefix matching either pattern, including git.corp.example.com/xyzzy, rsc.io/private, and rsc.io/private/quux.

For fine-grained control over module download and validation, the GONOPROXY and GONOSUMDB environment variables accept the same kind of glob list and override GOPRIVATE for the specific decision of whether to use the proxy and checksum database, respectively.

For example, if a company ran a module proxy serving private modules, users would configure go using:

GOPRIVATE=*.corp.example.com
GOPROXY=proxy.example.com
GONOPROXY=none