GetOTP is described as 'saves your time and hassle by providing a fast and convenient OTP flow. With just a few lines of code and our simple web API you can quickly implement a secure authentication flow so you can focus on building your service'. There are eight alternatives to GetOTP for a variety of platforms, including Android, Online / Web-based, Mac, iPhone and Android Tablet. The best alternative is Authy, which is free. Other great apps like GetOTP are andOTP (Free, Open Source), FreeOTP+ (fork of FreeOTP) (Free, Open Source), Twilio (Freemium) and Nexmo (Paid).
Twilio is a web-service API that lets you use your existing web languages and skills to build voice and SMS applications. We focus on building a simple, powerful, pay-as-you-go communications platform so that you can focus on what you do best.
nOTP is an innovative product that allows you to authenticate and verify users without any actions from their end. Available as an SDK currently for Android phones, it works much faster than the typical OTP verification.