[skrtskrt]

you can provision in API/IP-enabled "mobile" number through a provider like Twilio or competitors, do everything in software (or do nothing regarding custom software and just enable SMS forwarding in the provider's UI), and pay fractions of pennies per SMS, plus a monthly fee for the number like $1.50.

See my comments elsewhere in thread, but a "VOIP" number is a ridiculously tiny corner case in the world of telco, hence lack of support.

[rsync]

I wish this were the case - believe me, I have tried many different API provided phone number endpoints and they are discriminated against by banks, google, etc.

In fact, twilio even started offering special numbers that are flagged and "vouched for" that should be treated as non-VOIP ... but they aren't.

If you really need it to work, it needs to be a number from a physical SIM card.

[pxeboot]

Unfortunately, many services have started blocking any number not currently associated with AT&T, T-Mobile, Verizon or a major regional carrier. Even legitimate 'mobile' numbers from tiny carriers and MVNOs are getting blocked.

[vorpalhex]

Nope. I had a "burner" voip used for providing to retailers/etc who wanted a phone number for no reason. I would migrate the number yearly. Unfortunately those are now rejected.