Nexmo

Provides APIs for SMS, voice, and phone verifications, aiding navigation in communication.

HQ: San Francisco, USA
Founded: 2010
Focus: Communication APIs
Founders: Tony Jamous, Rami Essaid
Funding: Series C, $18M
Sources: https://www.nexmo.com/about, https://techcrunch.com/2016/01/12/nexmo-raises-18m-series-c-funding/