How to do SMS verifications for 100 users without spending absurd amounts of money?

I often run into the issue that I need to create accounts for 20+ users and it becomes more and more common that you can’t get around SMS verification. Unfortunately there is no budget to buy a SIM card for every user, not to mention that it would be a pain in the ass to insert these cards one by one into a cellphone, in order to do all the verifications.

I’ve been wondering for a while if you can’t just buy one SIM card with an arbitrary amount of extension numbers that all go to the same phone, but I can’t find anything the like.
I also have not been able to find a provider that simply skips the need for SIM cards entirely, doing everything over the Internet.

I have tried some services that offer receiving SMS online and I’ve also tried some services that are specifically designed around SMS verification, but they were either expensive or very shady and unreliable.

Is there no cheap way to do this?

I mean I can buy a standard landline and have as many phone numbers as I want using extension numbers. Do I really have to pay for every for every single cellphone number?

Twilio is $1.15/month per number and less than a cent for each SMS. They have a nice API that you can automate provisioning and sending/receiving with. However, services that require SMS verification know about these type of services and often refuse using phone numbers from them.

Maybe there’s another way to create the user accounts? I know of several cloud service providers that require SMS verification for some types of user accounts, but creating any number of other types of user accounts can be done after verifying a domain name.

$1.15/month is definitely better than most offers I have seen, but it still seems rather expensive considering that I only need to receive an SMS 3 times a year or so.

I wonder how cellphone numbers even work. Is it like with IPv4 addresses where there is only a very limited amount available?

The most recent example for accounts that required SMS verification was ChatGPT. If you know any ways around that I’d be happy to hear it, but I don’t think it’s possible.

I haven’t tried it, but ChatGPT has a sign-in with Google option, and you can create 50 Google user accounts with Cloud Identity Free if you verify a domain name (add a DNS TXT record).

Edit: tested it, ChatGPT still wanted a phone number.

What is it called when a website is passwordless, but just sends you a code to login? I think Uber and Lyft do it that way. They just have an account tied to your phone number.

that is 2 VERY different examples. your ‘landline’ example is a NAT, where your ‘cellphone’ example is purchasing individual public IP addresses.

yes, you must pay for every publicly available number, extension numbers after dialing are handled internally. regardless of Cellular or POTS.

Asterisk supports SMS to some degree, you could build an on-prem asterisk server and give it 1 public number and have it do what you need, maybe. there are some IFs there.

Managing SMS verification for a bunch of users can be a real headache, especially when you’re on a budget and don’t want to deal with dozens of SIM cards. I ran into something similar when setting up test accounts for a project. Instead of trying to juggle physical SIM cards, I found that using phone numbers for verification from services like Tardigrada made things so much easier. It’s all online, so no swapping SIMs or using a phone over and over. Plus, it’s reliable and not one of those sketchy options. It definitely helped keep costs down and kept the whole process a lot more manageable.

I agree that there are a lot of online SMS confirmation services that don’t work and aren’t reliable, but the one I’ve found and have been using for some time is https://anonymsms.com/.
They offer temporary phone numbers based on real SIMs that can be used to receive SMS codes. What I like most is that their numbers actually work, as they are frequently replaced with new ones.

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Watch this and skip SMS verification alltogether.

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