[ss3000]

> Also some services straight up refuse to send SMS to cloud phone providers meaning you can't sign up for certain services that needed a verified phone number (unless they had an option to receive a call with the verification code which worked like 25% of the time).

I've ran into the same issue with this on Google Voice. Though sometimes I wonder if I could have gotten the best of both worlds by just porting a number from a traditional carrier to Google Voice/Twilio.

Are these kinds of checks only against the number itself? Or is there some kind of dynamic registry?

[anderspitman]

Google Voice has been my primary number for about 10 years and it usually works.

My main concern is what to do when Google kills it.

[rsync]

"Are these kinds of checks only against the number itself? Or is there some kind of dynamic registry?"

In general it is much simpler than that. These companies are sending you these SMS messages not from a "normal" phone number (xxx-yyy-zzzz) but from a shortcode (xxxxx). The "from" is a shortcode and only mobile numbers can receive SMS from shortcodes.

So if your number is not a "mobile" number, you might still receive SMS from other real phone numbers, but you cannot receive SMS from shortcodes.

Twilio, for instance, does not provide mobile numbers. Period. So even if you port a mobile number to twilio, as soon as it is theirs, you cannot receive SMS from shortcodes.

[_-___________-_]

Your assertion that only mobile phones can receive SMS from shortcodes is not true in general, and additionally many verification SMS are not sent from shortcodes.

[rsync]

Only true mobile phone numbers can receive SMS from shortcodes.

Here is a list of carriers that are properly registered to receive SMS from shortcodes:

https://usshortcodedirectory.com/faq/what-wireless-carriers-...

"... short code carriers have arrangements to exchange messages with mobile phone numbers only ..."[1]

[1] https://support.twilio.com/hc/en-us/articles/223133447-Not-R...

[_-___________-_]

I guess this is a US thing, then. It's definitely not true in general, as I said.

[skinnymuch]

I’m almost certain the check is against what the number is behind. Also the opposite situation - Google Voice to carrier would result in issues if carrier to GV was fine. Not the case however.

The number needs to be non-VoIP. Off the top of my head, Uber, Lyft, Craigslist all require non-voip which means no Google Voice.

[_-___________-_]

They have databases that they look up, but they're notoriously inaccurate. If you can use a number from another country (not always possible since some services require an in-country number, but a surprising number don't) you'll often find it works better, especially if you choose a country where the database provider might have less access to information about which ranges are assigned to which providers.

[wtdo]

I have a number in Google voice that I ported from a regular old T-Mobile SIM years ago. I haven't seen many that won't send me an SMS message, but when I do, they are usually banks. I don't think it much matters where the phone number originates.