Overview of Microsoft Teams Architecture｜Mastering Microsoft Teams Bots 1.2

1.2 Overview of Microsoft Teams Architecture

Before we dive into the technical specifics of building bots, it’s important to understand the environment in which they operate. Microsoft Teams isn’t just a messaging app — it’s a full-fledged platform designed to be extensible, modular, and deeply integrated with Microsoft 365 services.

If you think of Teams as a digital office, then its architecture is the blueprint. And like any blueprint, knowing the layout helps you build with intention and power. In this section, we’ll explore the fundamental components of Teams from a developer’s point of view, so you can see where your bot fits in — and where it can shine.

What Is Microsoft Teams, Architecturally?

• Channels and Teams: Organizational containers that group people, conversations, files, and tabs.
• Tabs: Web-based content embedded in a channel or chat — dashboards, apps, forms, etc.
• Messaging Extensions: Enable in-line search and actions directly from the message composer.
• Bots: Agents that receive and respond to user messages or trigger workflows.
• Webhooks and Connectors: Lightweight ways to push messages or notifications into Teams.
• Microsoft Graph API: Unified access to Teams data, calendars, users, files, and more.

Teams as a Platform: More Than Messaging

One of the most powerful aspects of Teams is that it brings identity, communication, and context together. Every interaction inside Teams is enriched by who the user is, where they are, and what data they can access.

Developers can:

• Tailor content based on user identity or role
• Securely access Microsoft 365 resources via authentication
• Build once and deploy across tenants with consistent UX

For example, a Daily Planner Bot can appear in a Sales channel tab, read a user’s calendar, log tasks, and send reminders — all using tabs, bots, Graph API, and authentication.

Extending Teams with Apps

Anything added to Teams beyond its core features is considered an "app." Your bot will be packaged as such, and defined using a Teams App Manifest.

A Teams app can include:

• Bots (1:1 chat, group chat, channel)
• Static or configurable tabs
• Messaging extensions
• Connectors and webhooks
• Azure AD SSO integration
• Adaptive Cards and Task Modules

Where Do Bots Fit In?

Bots live at the heart of the interactive layer:

1. The user sends a message (or command) to the bot
2. The message is routed to your bot’s backend service (hosted on Azure or elsewhere)
3. Your service processes the message and responds with text, cards, or actions

Bots can also be proactive — initiating conversations, reminders, and alerts based on background events.

Why Architecture Matters

Understanding Teams architecture helps you design with intent:

• Decide between tabs, bots, or messaging extensions
• Plan for authentication, API access, and permission scopes
• Think about multi-tenant scenarios and localization early

With this foundation in place, you're ready to build. In the next section, we’ll set up your development environment and create your first Teams bot — a simple, working example that sets the stage for everything to come.