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Bot Framework SDK for .NET


The Bot Framework SDK for .NET is a powerful framework for constructing bots that can handle both free-form interactions and more guided conversations where the user selects from possible values. It is easy to use and leverages C# to provide a familiar way for .NET developers to write bots.

Using the SDK, you can build bots that take advantage of the following SDK features:

  • Powerful dialog system with dialogs that are isolated and composable
  • Built-in prompts for simple things such as Yes/No, strings, numbers, and enumerations
  • Built-in dialogs that utilize powerful AI frameworks such as LUIS
  • FormFlow for automatically generating a bot (from a C# class) that guides the user through the conversation, providing help, navigation, clarification, and confirmation as needed


On July 31, 2017 breaking changes have been implemented in the Bot Framework security protocol. To prevent these changes from adversely impacting your bot, you must ensure that your application is using Bot Framework SDK v3.5 or greater. If you've built a bot using an SDK that you obtained prior to January 5, 2017 (the release date for Bot Framework SDK v3.5), be sure to upgrade to Bot Framework SDK v3.5 or later.

Get the SDK

The SDK is available as a NuGet package and as open source on GitHub.


The Bot Framework SDK for .NET requires .NET Framework 4.6 or newer. If you are adding the SDK to an existing project targeting a lower version of the .NET Framework, you will need to update your project to target .NET Framework 4.6 first.

To install the SDK within a Visual Studio project, complete the following steps:

  1. In Solution Explorer, right-click the project name and select Manage NuGet Packages....
  2. On the Browse tab, type "Microsoft.Bot.Builder" into the search box.
  3. Select Microsoft.Bot.Builder in the list of results, click Install, and accept the changes.

Get code samples

This SDK includes sample source code that uses the features of the Bot Framework SDK for .NET.

Next steps

Learn more about building bots using the Bot Framework SDK for .NET by reviewing articles throughout this section, beginning with:

  • Quickstart: Quickly build and test a simple bot by following instructions in this step-by-step tutorial.
  • Key concepts: Learn about key concepts in the Bot Framework SDK for .NET.

If you encounter problems or have suggestions regarding the Bot Framework SDK for .NET, see Support for a list of available resources.