SMS Plus - SMS Plus app offers features that let you forward text messages through internet connection as well as through other social media platforms.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
NetSfere Secure Messaging - NetSfere Secure Messaging is a secure messaging app that enables you to send messages by using 256-bit device-to-device encryption features.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Enigmail - Security extension to Mozilla Thunderbird and SeaMonkey
Plivo - Plivo simplifies your customer engagement.