but so far at least I’m happy with the bandwidth.
Oh for sure, it’s boatloads and I love it… but I’m in the market for a /28. I want to hand them like $40 extra a month. LET ME PAY YOU QUANTUM/LUMEN/CENTURYLINK/LEVEL3. It’s effectively free money as once it’s setup there’s nothing that changes or goes down. There’s so little maintenance/upkeep cost to it that I just don’t understand why they don’t want to print free money.
TOTP is cheaper.
SMS is actually expensive at scale. An example would be Signal, the messenger app that doesn’t use SMS. They have overhead for sending backup codes/new account creation/Verification/etc… https://www.wired.com/story/signal-operating-costs/ 6 million a year. API integrations for SMS messages/codes are still like 1-5 cents per message.
TOTP’s requirements? A reasonably accurate clock on the server, and storing the shared secret in a database.