Google voice numbers can be detected, even you have one ported from say AT&T. Twillio's API marks it as Google Voice. And for dual SIM phones: > An iPhone XS,

Google voice numbers can be detected, even you have one ported from say AT&T. Twillio's API marks it as Google Voice. And for dual SIM phones: > An iPhone XS, iPhone XS Max, iPhone XR, Source: https://support.apple.com/en-us/HT209044 https://support.apple.com/en-us/HT209044 That's 6 generations of iPhone that have dual SIM, in which there is at least 1 eSIM.