Twilio - Brings voice and messaging to your web and mobile applications.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.
Invision - Prototyping and collaboration for design teams
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Sketch - Professional digital design for Mac.