Azure IoT service SDK provides the code that is used in building an IoT application that directly works with the IoT Hub. It will enable you to manage devices, read messages sent by devices, or even send commands to devices to control actions at the device end.

The GitHub URL to download these open source SDK's are:

• Azure IoT service SDK for .NET
• Azure IoT service SDK for Node.js
• Azure IoT service SDK for Java
• Azure IoT service SDK for Python

Azure IoT gateway SDKs are used to simplify the connectivity to IoT Hub when we have scenarios which vary drastically between industries, and even between customers within the same industry. The Azure IoT gateway SDK can be used to implement custom-made IoT solutions for your scenario. The device SDKs can be used to implement an IoT client that facilitates connectivity to the cloud. It simply uses the supported communication protocol, it will extract and process the data using the protocol supported before sending it to the cloud.