The C SDK is the basis for ThingWorx Edge SDKs and the Edge MicroServer (EMS). You can compile C SDK applications on any platform and even run it without an operating system. Using the C SDK for your application means least amount of RAM, processing power, and disk space, frequently requiring less than 200 kilobytes. The C SDK is also the only SDK that is distributed as source code.
The Java SDK is especially useful if you are integrating with an application that uses a Java-based API. While applications based on the Java SDK tend to use more RAM, processing power, and disk space than a C SDK equivalent application, they typically take less time to develop. To use it, you will need a platform with a supported Java Virtual Machine.
Use the Microsoft .NET SDK when integrating with a .net based application or if your team typically works with Microsoft technologies. It may only be used on Windows based machines.
The iOS SDK integrates with Apple's iOS based devices like the iPhone, iPad, and iPod Touch. It can be used as a bridge where the iOS based device collects data from a source, be it Bluetooth or Wi-Fi, processes it, and communicates with the ThingWorx Platform.