| > How, specifically, do other services detect this? I don't actually know specifically. I assume there are two different ways: - The service is using Verify / Authy, which is owned by Twilio so likely Twilio themselves discourage it - Looking up the number either through Twilio or some sort of central subscriber database. All virtual numbers are described as virtual numbers. > Are you aware of mechanisms to avoid this detection/blocking that don't require using a "real" number. Definitely gets into ethically gray areas since that would be super useful to nefarious people. I don't actually know for sure. I know from the recent Blizzard mobile 2FA controversy that this issue expands to also prepaid phone numbers. So I don't know of a definitive way to get around it beyond using a postpaid number. Somewhat related, near the end of my above mentioned service, I had pivoted into trying to launch a "21st century phone service" complete with SIM cards provided by Twilio. The issue? They were still considered virtual numbers. At the time, in Twilio's defense, I was somewhat misusing their service because their SIMs were intended for IoT purposes not actual cellphone usage. That's all to say, it's likely provider / subscriber level vs something you can individually spoof. |