The android SMS retrieval API  has been around for some time and it helps many app developers reduce the friction verifying phone numbers (which are used as an identity token, a communication channel and as a mechanism to reduce abuse in account creation / recover).
For the last few years, we’ve seen a growing number of web developers looking into a similar capability, so we started we exploring some early options/alternatives in a explainer .
There are a number of ways in which phone numbers are used , so we are looking into deliberately narrowing down the scope to phone number verification (e.g. we make an assumption that the phone number is already known).
We would love to get some early guidance, recommendations and developer interest if you are interested in this area here !
 [Proposal] Sign up API for Web  https://developers.google.com/identity/sms-retriever/overview  https://github.com/sso-google/sms-otp-retrieval  https://github.com/sso-google/sms-otp-retrieval/issues/new