Um, the twilio customer can be the spammer. They can send messages to anyone they want to target. Twilio IS running what is effectively an open rely.
To the degree twilio's business model depends on allowing its customers to send to whomever they want (which I assert it does), they CAN NOT let those customers send spam - full stop - end of discussion. If you don't understand why this is critical to twilio - I don't know what to say. MOST users do not want SMS spam.
Seriously, if you need to send SMS spam, use one of the "bulletproof" SMS spam players.
Even if we say customer is not a spammer, they are sending mail out to a wide variety of third party networks. In email land a closed SMTP server only forwards messages to an internal network or server under that admins control. As soon as you start blasting spam out to third party systems you are not a closed relay. That's literally how the verizon and other carrier systems will see this source of SMS spam and phishing.
The point about the reputation of IP or carrier / telephony origintion numbers / space remains. The use case here is prohibited by twilio's terms of service. Maybe just comply with those or find another provider.
An open relay is different from what you describe. My email account is not an open relay just because I can spam whomever I want from it, and neither is my twilio account.
And I don't need to send sms spam. If it was blocked on the way out, that'd be fine.
To the degree twilio's business model depends on allowing its customers to send to whomever they want (which I assert it does), they CAN NOT let those customers send spam - full stop - end of discussion. If you don't understand why this is critical to twilio - I don't know what to say. MOST users do not want SMS spam.
Seriously, if you need to send SMS spam, use one of the "bulletproof" SMS spam players.
Even if we say customer is not a spammer, they are sending mail out to a wide variety of third party networks. In email land a closed SMTP server only forwards messages to an internal network or server under that admins control. As soon as you start blasting spam out to third party systems you are not a closed relay. That's literally how the verizon and other carrier systems will see this source of SMS spam and phishing.
The point about the reputation of IP or carrier / telephony origintion numbers / space remains. The use case here is prohibited by twilio's terms of service. Maybe just comply with those or find another provider.