Unified manifest support for Word, Excel, PowerPoint, and Outlook makes it possible for developers to build a single app that works across Microsoft 365 apps, creating a more consistent experience for users and a simpler deployment model for IT admins.

Mailbox requirement set 1.16 is now generally available for Outlook add-ins. This release reflects our continued investment in closing the gap between COM/VSTO and web add-ins, with a focus on message and information security. Mailbox 1.16 introduces APIs and platform updates that enable your add-in to: Handle message de...

Read how inline image attachments are handled when they’re programmatically added to a mail item's signature or body in Outlook on the web and the new Outlook for Windows

We’re improving how add-ins appear on the ribbon in Outlook on the web and the new Outlook on Windows. These updates make add-ins easier to find and align the experience across Outlook clients.

Customers have asked for greater user control over add-in launch behavior in Office. We are making three adjustments to our platform to address this customer feedback.

Read about new and exciting features now available in the Office Add-ins ecosystem for Ignite 2025. Learn about platform updates, developer experience improvements, and store enhancements.

We are updating how inline images are represented in the HTML body of Outlook emails in Outlook on the web and the new Outlook for Windows. This change may impact how your add-in identifies and processes inline images when using the attachment ID.

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.

The Office Platform team has been busy working on improvements to the platform since we last reported. This blog covers the new features from the office-js team announced at Ignite 2024.

In this blog, the Office Platform team announces the new capabilities and features announced at Build 2024.