Microsoft 365 Developer Blog
A developer platform for building collaborative apps for hybrid work
Latest posts
Dev Proxy v0.28 with LLM usage and costs tracking
The latest version of Dev Proxy introduces a new ability to help you understand language models’ usage and costs in your applications, alongside many improvements to mocking, TypeSpec generation, and plugin flexibility.
Build like Microsoft: Developer agents in action
Take a deep dive into Athena, an AI-powered collaborative agent, to learn how it was built and how to create your own version of Athena right within Microsoft Teams.
Office Add-ins announces Copilot agents with add-in actions and more at Build 2025
As part of the expanding capabilities for agents across Microsoft 365, Office Platform announces add-in actions for Copilot agents are available in preview. This blog is an overview of all the new capabilities across the platform: APIs, developer tools, and add-in distribution options—making it simpler to build new or iterate on JavaScript add-ins.
Introducing the Agent Store: Build, publish, and discover agents in Microsoft 365 Copilot
We’re excited to introduce the Agent Store — a centralized, curated marketplace that features agents built by Microsoft, trusted partners, and customers. The Agent Store offers a new, immersive experience within Microsoft 365 Copilot that enables users to browse, install, and try agents tailored to their needs.
Introducing the Microsoft 365 Agents Toolkit
Read how the Microsoft 365 Agents Toolkit, an evolution of Microsoft Teams Toolkit, is designed to help developers build agents and apps for Microsoft 365 Copilot, Microsoft Teams, and Microsoft 365.
Introducing Microsoft 365 Copilot APIs
Learn how Microsoft 365 Copilot APIs allow you to build solutions grounded in your organization’s content, context, and permissions, without needing to relocate or duplicate data.
Exchange Web Services code analyzer and usage report
We are less than 18 months away from the retirement of Exchange Web Services. Start planning your migration from EWS to Microsoft Graph.
Nested App Authentication: Now generally available across Microsoft 365
Get started with Nested App Authentication, a modern protocol for simplifying authentication for Personal Tab Teams apps that run across Microsoft 365.
Announcing the updated Teams AI Library and MCP support
Discover the new and improved Teams AI Library, designed to help developers create even more powerful agents for Microsoft Teams.