Twilio - Brings voice and messaging to your web and mobile applications.

Flowroute - Flowroute provides direct access to telephony resources - such as calling, messaging (SMS & MMS), call routing, SIP Trunking and Communication APIs.

Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.

Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates

Skyetel - We are a nation-wide SIP Trunk Provider that excels where it counts: high availability, awesome call quality, and powered entirely by renewable energy.

Podium - Podium helps your business get more customer reviews, manage customer feedback, customer interaction, and online review management from one software.