What are some alternatives?
When comparing BulkSMS and MessageBird, you can also consider the following products
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Twilio - Brings voice and messaging to your web and mobile applications.
Infobip - A2P messaging platform for enterprises, resellers & mobile operators with global network coverage.
Plivo - Plivo's Voice API enables businesses to build Voice apps to reach customers globally in 200+ countries. Try Plivo's Voice API for free. Instant Sign Up.
Avochato - Text messaging for your business.
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.