How to use OTP MFA with gem CLI.

Multi-factor authentication (MFA) using OTP works by using an authenticator app on your phone to generate a one-time password (OTP) that you then enter at the command line. This documentation explains how to use OTP multi-factor authentication (MFA) if you have configured it. For WebAuthn instructions, see “Using WebAuthn multi-factor authentication in command line”.

When you have only enabled OTP MFA, and your MFA level is UI and API, we will ask to you to provide an OTP for gem signin, gem push, gem owner --add and gem owner --remove. Check setting up multi-factor authentication for enabling MFA.

This level requires a recent enough gem command as shipped with Ruby 2.6+, or RubyGems 3.0+.

You can preemptively pass an OTP code using --otp flag or else we will prompt for the OTP code when required:

$ gem signin
Enter your RubyGems.org credentials.
Don't have an account yet? Create one at https://rubygems.org/sign_up
Email:   gem_author@example
Password:

You have enabled multi-factor authentication. Please enter OTP code.
Code:   111111
Signed in.

Passing OTP as flag:

$ gem signin --otp 111111
Enter your RubyGems.org credentials.
Don't have an account yet? Create one at https://rubygems.org/sign_up
Email:   gem_author@example
Password:

Signed in.

Note that gem signin only fetches and stores your rubygems.org api key. gem signin is not equivalent to creating a user session. We will check for OTP code every time you use any of the commands mentioned above.

Publishing a gem after signing in from cli:

$ gem push hello-0.0.1.gem
Pushing gem to https://rubygems.org...
You have enabled multi-factor authentication. Please enter OTP code.
Code:   111111
Successfully registered gem: hello (0.0.1)