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how-to-device-twins.md

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title Get started with Azure IoT Hub device twins
titleSuffix Azure IoT Hub
description How to use the Azure IoT SDKs to create device and backend service application code for device twins.
author cwatson-cat
ms.author cwatson
manager lizross
ms.service azure-iot-hub
ms.devlang csharp
ms.topic how-to
ms.date 09/10/2024
zone_pivot_groups iot-hub-howto-c2d-1
ms.custom mqtt, devx-track-csharp, devx-track-dotnet

Get started with device twins

Use the Azure IoT Hub device SDK and service SDK to develop applications that handle common device twin tasks. Device twins are JSON documents that store device state information including metadata, configurations, and conditions. IoT Hub persists a device twin for each device that connects to it.

You can use device twins to:

  • Store device metadata from your solution back end
  • Report current state information such as available capabilities and conditions, for example, the connectivity method used, from your device app
  • Synchronize the state of long-running workflows, such as firmware and configuration updates, between a device app and a back-end app
  • Query your device metadata, configuration, or state

For more information about device twins, including when to use device twins, see Understand and use device twins in IoT Hub.

[!INCLUDE iot-hub-basic]

This article shows you how to develop two types of applications:

  • Device apps can handle requests to update desired properties and respond with changes to reported properties.
  • Service apps can update device twin tags, set new desired properties, and query devices based on device twin values.

Note

This article is meant to complement Azure IoT SDKs samples that are referenced from within this article. You can use SDK tools to build both device and back-end applications.

Prerequisites

  • An IoT hub

  • A registered device

  • If your application uses the MQTT protocol, make sure that port 8883 is open in your firewall. The MQTT protocol communicates over port 8883. This port may be blocked in some corporate and educational network environments. For more information and ways to work around this issue, see Connecting to IoT Hub (MQTT).

:::zone pivot="programming-language-csharp"

[!INCLUDE iot-hub-howto-device-twins-dotnet]

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:::zone pivot="programming-language-java"

[!INCLUDE iot-hub-howto-device-twins-java]

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:::zone pivot="programming-language-python"

[!INCLUDE iot-hub-howto-device-twins-python]

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:::zone pivot="programming-language-node"

[!INCLUDE iot-hub-howto-device-twins-node]

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