TextBee
Free tierOpen sourceFrom the lab
Open-source SMS gateway that runs on your Android phone
Vonage
Paid
Communications APIs for SMS, voice, video and messaging
The gist
Vonage offers REST APIs to send and receive SMS worldwide, plus voice, video and messaging channels such as WhatsApp. It is for developers and businesses that add communication features to their applications.
Vonage alternatives
Compare all 3 →The Gist, weekly