Agora.io!

Twilio is a web-service API that lets you use your existing web languages and skills to build voice and SMS applications. We focus on building a simple, powerful, pay-as-you-go communications platform so that you can focus on what you do best.

Plivo is a voice and SMS API platform that enables developers and enterprises to build powerful apps with great features. With 24/7 free tech support and low prices, Plivo can help your business scale globally.

SightCall offers comprehensive real-time video APIs and Mobile SDKs that makes it simple to embed video calling and video conferencing into any application. SightCall provides a WebRTC Platform for healthcare, customer service and enterprise collaboration and has prepackaged integrations for Salesforce and Zimbra.

If your reps or customers are remote, you should check out Blitzz.co.

Sinch is a powerful voice and messaging SDK that lets you bring your apps to life with VoIP and WebRTC technology. Simplicity is at its core and you can get your first app up and running in a few lines of code and a matter of minutes.

Reach any customer on any mobile phone, anywhere, today!

SAAS, cloud based messaging (A2P-application to person), with SMS, email and fax as main channels, all reachable from the same sending simultaneously with answer back traceability and thread follow up. Link-SMS, Protected messages and signed messages using e-ID. Free trial.

In less than 5 minutes, your customers or site visitors can call you directly from your website with a simple click of a button. Talk to your customers before they leave.