SMS Privacy is described as 'Allows you to buy mobile phone numbers, using Bitcoin, with completely anonymous signup. We don't even take an email address if you don't want to supply one. You can send and receive SMS text messages on these anonymous numbers using our web interface' and is an website in the security & privacy category. There are more than 10 alternatives to SMS Privacy, not only websites but also apps for a variety of platforms, including SaaS, Chrome OS, Mac and Windows apps. The best SMS Privacy alternative is Twilio. It's not free, so if you're looking for a free alternative, you could try Tellephant or D7SMS. Other great sites and apps similar to SMS Privacy are Plivo, Clockwork SMS, Flashy.app and SendSMSGate.