Add password-free email & SMS authentication to your web app

Would you recommend this product?
No reviews yet
This is really cool and a trend I have been seeing a lot lately, like with Slack's "magic link". Curious to see where pricing ends up for this and how practical it will be for smaller web apps compared to the existing free method.
I like the native mobile APPS to authenticate more, but is an alternative, in Spain sending SMS its really expensive for example. I use Google Authenticator and Authy, but they are really costly. Any cheap or free friendly alternative?