Twilio - Brings voice and messaging to your web and mobile applications.
Lets Chat - Open source self-hosted chat app for small teams
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.
Telegram API - We offer two kinds of APIs for developers. The Bot API allows you to easily create programs that use Telegram messages for…
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
TapTalk.io - TapTalk.io is a complete in-app chat SDK and messaging API - Easy integration and customizeable.