Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.

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

Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.

Plivo - Plivo simplifies your customer engagement.

Facebook Messenger - Facebook Messenger is a faster way to message.

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