As far as I know, Twilio doesn't distinguish between SMS messages coming from within Twilio and those sent from other networks. If that's true, all messages wo

As far as I know, Twilio doesn't distinguish between SMS messages coming from within Twilio and those sent from other networks. If that's true, all messages would still need to go out and traverse the SMS network and leave Twilio's infrastructure before landing on the other side. I think this should provide reliable insights into message success/failure at the network level. It wouldn't show any localized issues like if a cell tower is down, though. All that being said, I haven't done any serious research into how SMS are sent and what the network looks like. Would be an interesting thing to look into!