Microsoft Teams is Microsoft's platform for communication at work: one-to-one and group chats, channels (topic-based spaces inside a team), online meetings and video calls, phone calls and file sharing. It runs on desktop, web and mobile, and Microsoft states that the Teams platform has over 320 million monthly active users.
Developers extend Teams with apps and agents. An agent is a program that holds a conversation with users; built with the Teams SDK, it can answer in natural language with large language models (LLMs), and personal apps use conversational bots that talk to one user directly. One codebase can deploy the same agent to Teams, Outlook and Microsoft 365. To list an app in the Teams Store, a developer submits it through Partner Center. A Microsoft validator then tests it on desktop, web and mobile clients against the commercial marketplace certification policies and sends a test report, which Microsoft aims to deliver within 24 working hours. Apps in the Teams Store are listed automatically in the Microsoft commercial marketplace.
A free version allows messages and calls of up to 60 minutes. Business plans are subscriptions priced per user.