gmc auth

Authenticate against the Merchant API. See Authentication for the credential resolution order and the service-account / ADC options.

gmc auth login

Sign in with your Google account in the browser (OAuth). The login is stored per profile.

gmc auth login
gmc auth login --no-browser   # print the authorization URL instead of opening a browser

Option	Description
--no-browser	Print the authorization URL instead of opening a browser (headless / remote)

gmc auth logout

Remove the stored OAuth login for the current profile.

gmc auth logout

gmc auth whoami

Show the resolved credential identity — no network call.

gmc auth whoami
gmc auth whoami --json   # { "email": "...", "projectId": "..." }

gmc auth test

Verify the credential by requesting an access token (network).

gmc auth test

A failure exits 3 (auth). For a full diagnosis including Merchant API reachability, use gmc doctor.