On top of standard SMS and MMS message support, Google's flagship messaging app supports RCS messaging (if your carrier supports it). Messages is the king of SMS on Android, with over one billion downloads. SMS messaging apps come in two flavors: apps that work with your existing phone plan, essentially replacing your default messaging app, and apps that provide you with an additional phone number from which to text, often with some limitations. In other words, the venerable messaging standard isn't going anywhere any time soon. In addition to the interpersonal texting we're used to, SMS has become the de facto method of one-time password delivery. Even though SMS messaging isn't as prevalent internationally, it's still one of the most common forms of messaging in the US.
