Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Plivo - Plivo simplifies your customer engagement.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.