Microsoft.Teams.Apps

Microsoft.Teams.Apps

A high-level framework for building Microsoft Teams bots in .NET. Built on top of Microsoft.Teams.Core, it provides Teams-specific activity types, a typed routing and handler system, OAuth authentication flows, Teams API clients, and streaming message support.

Key Features

• Typed Activity Routing — Register handlers for specific activity types (OnMessage, OnAdaptiveCardAction, OnQuery, etc.) with type-safe contexts
• Teams Activity Schema — Rich type hierarchy (MessageActivity, InvokeActivity<T>, ConversationUpdateActivity, etc.) with polymorphic deserialization
• OAuth Flows — Built-in SSO token exchange, sign-in cards, and token management via OAuthFlow
• Teams API Clients — Typed clients for conversations, members, teams, channels, meetings, and batch operations
• Streaming Messages — Progressive response updates via TeamsStreamingWriter
• Fluent Configuration — Chainable handler registration and AppBuilder for setup

Installation

dotnet add package Microsoft.Teams.Apps

Quick Start

using Microsoft.Teams.Apps;
using Microsoft.Teams.Apps.Handlers;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddTeamsBotApplication();

var app = builder.Build();
var teams = app.UseTeamsBotApplication(); // maps POST /api/messages

teams.OnMessage(async (context, ct) =>
{
    await context.SendActivityAsync($"You said: {context.Activity.Text}", ct);
});


app.Run();

Handler Registration

Handlers are registered as extension methods on TeamsBotApplication and can be chained:

Messages

using Microsoft.Teams.Apps.Handlers;
// All messages
teams.OnMessage(async (context, ct) => { ... });

// Regex pattern match
teams.OnMessage(@"^help$", async (context, ct) =>
{
    await context.SendAsync("Here's how to use the bot...");
});

Invoke Activities

// Adaptive card actions
teams.OnAdaptiveCardAction(async (context, ct) =>
{
    var value = context.Activity.Value;
    return new InvokeResponse(200);
});

// Message extension search
teams.OnQuery(async (context, ct) =>
{
    var query = context.Activity.Value.Parameters["queryText"];
    return new InvokeResponse<MessageExtensionResponse>(200, response);
});

// Task modules
teams.OnFetchTask(async (context, ct) => { ... });
teams.OnTaskSubmit(async (context, ct) => { ... });

// Link unfurling
teams.OnQueryLink(async (context, ct) => { ... });

Main Types