Bot Authentication and Identity｜Mastering Microsoft Teams Bots 2.3

2.3 Bot Authentication and Identity

Now that your bot can respond to messages, it’s time to teach it who it’s talking to — and what it’s allowed to do.

In the world of Microsoft Teams bots, authentication is the bridge between simple interaction and meaningful functionality. Without it, your bot is just a chatbot. With it, your bot can access calendars, manage tasks, fetch files, and personalize conversations based on who the user is.

This section covers how identity works in Microsoft Teams, what authentication options exist, and how to securely get access tokens to use with Microsoft Graph or your own APIs.

2.3.1 Why Identity Matters

Imagine building a sales assistant bot that says, “Here are your leads for today.” Without authentication, the bot has no idea who “you” are. It might show public data, or nothing at all. But with authentication, the bot can securely identify the user, access Microsoft 365 data (like Outlook, OneDrive, or SharePoint), and respond in a personalized way.

Identity turns your bot from a general-purpose tool into a trusted assistant.

2.3.2 Identity Basics in Teams

Every user in Microsoft Teams has a Microsoft Entra ID (formerly Azure Active Directory) identity. When a user interacts with your bot, Teams knows who they are — and can provide an identity token if requested.

Bots can:

• Know the user’s Teams identity (user ID, name, email)
• Request access tokens (with consent) to call Microsoft Graph on the user’s behalf
• Authenticate users against third-party systems (like your own API or Salesforce)

2.3.3 Authentication Options for Bots

There are three main approaches to authentication in Teams bots:

1. Azure AD OAuth 2.0 Flow
   The most powerful and flexible option. You use OAuth to request an access token for Microsoft Graph or your own resource. This requires user login and consent.
2. Single Sign-On (SSO)
   The smoothest experience for users. If your bot is installed in Teams and properly configured, it can receive a token silently (no popup) using Teams identity. This only works in personal or static tab contexts.
3. Bot Framework Authentication (OAuth Prompt)
   A mid-level approach using dialogs. The bot sends an OAuth card with a login button; the user signs in, and the bot receives the token. This works in both 1:1 and group chats.

2.3.4 SSO: The Gold Standard

Teams SSO is the most seamless option — no popups, no passwords. The bot can silently request an access token for Microsoft Graph with the user’s permission pre-consented by your admin.

To enable SSO, you need:

• A properly configured Teams app manifest with webApplicationInfo
• Bot registration in Azure with correct scopes (e.g., User.Read)
• Backend logic to exchange the SSO token for a Graph token (on-behalf-of flow)

This method gives your bot the ability to:

• Show user profile info
• Read calendars, files, teams, and more
• Call internal APIs that require authenticated access

2.3.5 Common Use Case: Fetching the User’s Name and Email

Here’s a simple flow using Graph API with authentication:

1. User sends a message to your bot
2. Your bot receives the Teams SSO token from context
3. Your backend exchanges it for a Graph token
4. Your bot calls https://graph.microsoft.com/v1.0/me
5. Your bot responds: “Hi Alex, I see your email is alex@contoso.com”

This small interaction opens the door to anything Graph can do — and it all begins with identity.

2.3.6 Security and Consent

Authentication always comes with responsibility. Bots must:

• Respect consent boundaries — only request the scopes you truly need
• Securely store access tokens (ideally in memory or encrypted storage)
• Handle token expiration and refresh gracefully

Never hardcode secrets, and always follow Microsoft’s recommendations on token storage, expiration, and revocation handling.

2.3.7 Summary

Authentication is more than just logging in — it’s about enabling your bot to do useful, secure, personalized work. Whether you’re accessing Microsoft Graph or your company’s own backend, identity is the cornerstone of intelligent bot behavior.

Authentication adds depth to your bot — allowing it to securely interact with users, access personalized data, and operate as more than just a scripted responder.

With identity in place, your bot is now ready to go beyond one-off replies. In the next section, we’ll explore how bots can manage conversations, handle incoming messages, and maintain context across interactions — the building blocks of meaningful dialogue inside Microsoft Teams.