Twilio

Twilio is the world's leading cloud communications platform, enabling developers to embed SMS, voice calls, video, WhatsApp, email, and authentication into any application via APIs. Its "programmable communications" model has powered two-factor authentication, delivery notifications, telehealth calls, and customer engagement at companies like Airbnb, Netflix, Lyft, and countless others. Twilio went public in June 2016 and acquired SendGrid for $2B in 2019.