The Client SDKs allows you to build in-app messaging and voice solutions. Android, iOS and JavaScript are supported.
The Server SDKs allow you to quickly get up and running with the Vonage APIs in your language of choice.
You use the Nexmo Command Line Interface (CLI) to manage your Vonage account and use Vonage API products from the command line.
The Vonage framework libraries can get you up and running with the Vonage APIs quickly and easily in your framework of choice.