I spent some time figuring out how to integrate coder with Google Auth. It's as simple as this

CODER_OIDC_ISSUER_URL=https://accounts.google.com
CODER_OIDC_CLIENT_ID=
CODER_OIDC_CLIENT_SECRET=
CODER_OIDC_EMAIL_DOMAIN="example.com"
CODER_OIDC_SCOPES=openid,profile,email
CODER_OIDC_SIGN_IN_TEXT="Sign in with Google"
CODER_OIDC_ICON_URL=/icon/google.svg

https://coder.com/docs/admin/auth#provider-specific-guides