> Have you tested that it works?

Yes. I wouldn't have mentioned it if it didn't work.

Here's a screenshot showing the Apple and PayPal 2FA codes I have received through Slack via Twilio...

https://i.imgur.com/bQYSbPZ.png

I also don't have any accounts with banks that are stupid enough to use SMS for 2FA [1] so I haven't needed to use my Twilio number for that purpose.

Using SMS for Gmail 2FA doesn't make any sense when Google supports U2F.

[1] https://motherboard.vice.com/en_us/article/mbzvxv/criminals-...

paypal also supports TOTP through an old trick. Look it up.

I tried to find the "old trick" but only end up on 404s or forum threads that end with "they must have closed that trick now".

Would you mind sharing a working source?

Perhaps they have close it now then. This was the source: https://medium.com/@dubistkomisch/set-up-2fa-two-factor-auth...

It's not shortcodes per se, those work fine for the most part.

Twilio/Google Voice (more generally, VOIP numbers) are explicitly being blocked (because it's possible to find out what type of number it is) at a number of services, likely to combat fraud.

I've found MSFT (Azure) and AWS to be recent examples of such services. Google itself does the same.

As further proof that I am not lying here's a screenshot from my Twilio messaging log...

https://i.imgur.com/6b3cg5L.png

62226 = PayPal and 51472 = Apple.