Nice job on authentication. A question arises for me, though. I can understand the cost of Yubikey and email authentication falls to the user. But how much d

Nice job on authentication. A question arises for me, though. I can understand the cost of Yubikey and email authentication falls to the user. But how much do you estimate the SMS will cost you as a fixed cost? Back-of-the-envelope calculation would say that the cost shouldn't be onerous, but I don't know how frequently your userbase logs in anew. Have you arranged a bundle or do you pay per message still? Pardon the questions and feel free to ignore them if I am prying. Thanks.