Twilio - Brings voice and messaging to your web and mobile applications.

ProTexting - ProTexting offers mobile marketing tools for businesses to communicate with their audience via SMS & MMS campaigns.

Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates

Clickatell - Simple, reliable mobile messaging cloud.

BulkSMS - SMS messaging service provider offering two-way SMS communication services.

ShoutOUT - All in one business texting tool to send personalized alerts, promotions, reminders, short links and marketing campaigns, for any SMEs (hotels, restaurants, education, non profits, Woocommerce, banks, healthcare, agencies, supermarkets, weddings)