There have always been competitors in this space. There used to be bunch of companies, and there are still several, that offered various levels of telephony integration, especially in the SMS/MMS space. I kind of view Twilio as the Stripe of the telephony world. Twilio came along and made a developer-friendly API around a bundle of services, where before you may have to use one service for one thing and another for something else. Or one provider may only reach some carriers and not others. Twilio kept it basic, not really building anything on top of their API, just selling the API itself. Other companies tried to compete against their own clients. For example, many SMS/MMS providers would offer an API, but then compete against their clients by also selling campaign management platforms or mobile marketing services.