One of the big barriers to entry in the space is spam whitelisting. Every time you send an SMS message, there's a chance the carrier flags it as spam and doesn'

One of the big barriers to entry in the space is spam whitelisting. Every time you send an SMS message, there's a chance the carrier flags it as spam and doesn't deliver it. Twilio and others try to give customers a higher chance of successful delivery. That comes with direct carrier relationships and stuff.