I have worked in this space - aside from WebAuthN, the spam/scam problem is tough for a SaaS Telco company because anti-spam/scam is directly at odds with a low

I have worked in this space - aside from WebAuthN, the spam/scam problem is tough for a SaaS Telco company because anti-spam/scam is directly at odds with a low-friction self-serve experience. You also have to realize that Twilio is not a Telco, they ride on top of big Telco company infrastructure and ultimately has to answer to big Telco, and big Telco is very risk averse and generally has to answer to regulators. So Twilio doesn't want spammers either because they get dinged, blocked, or marked as spam by the Telcos. Ultimately there's probably more that the underlying Telco infrastructure could do more to support anti-spam measures but these companies are dinosaurs that move very slowly. It's easy to deride them from the position of enlightened SaaS company employees, but they're the ones in the capital-intensive business of maintaining worldwide networks of copper wires in the ground, physical switches, systems designed in the 1980s or the 1950s and complying with incredibly complex and outdated regulatory structures. It's the "legacy system" of a developer's nightmare to the 100th power. Having a good flow for self-serve customers to sign up and get going is the cheapest way to get new business, and developers will not even look twice at you if it's hard to get going in a self-service manner on you platform. However, it's exactly that low friction that gets spammers going easily. So what do you do? You try to come up with heuristics and even ML models to identify bad actors early. It's an ongoing constant battle, a game of whack-a-mole where the moles have basically zero cost overhead, no legal entity associated with them, and can just keep popping up over and over and over forever. So you're staffing a fraud detection team of engineers, you have lawyers and finance people on this, you have customer service for customers who get caught as a false positive - it's all an extremely expensive pain in the ass.