Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Plivo - Plivo simplifies your customer engagement.
Newton Mail - Newton is a fully featured mail client available for Android, iOS, macOS and Windows.