Uhh, if you need a currently logged in device to bypass the phone number login, then I wouldn’t say it’s a “possible backup”. Phone number is the primary authentication mechanism for Authy.

If you have “Allow Multi-Device” enabled, your keys are stored on Authy’s servers. You simply download Authy on a new device, sign into your account and you are done.

How do you sign into your Authy account? For me, it asks to send an SMS to my phone.

Huh? I use Authy because it allows me to use TOTP codes, from multiple devices, including devices without cell service. I switched to it from Google Authenticator specifically for that reason.

Okay, so how do you sign in to Authy if you don’t have another signed in device handy? I believe the only options are phone call or sms.