Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
MyTask - MyTask is a centralized platform designed for office management, invoice management, and work management that allows a business to have the required service agility.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.