Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
Clearstream - Clearstream is a SMS marketing and online texting software.
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
E-goi - Email Marketing companies, SMS Marketing, software email marketing.
Ozeki NG SMS Gateway - Ozeki NG SMS Gateway is a powerful, reliable and flexible SMS Gateway application.
Maytapi - Serverless Whatsapp Api with Chat and Agent support.