Build powerful apps for Outlook and Microsoft 365

Reach hundreds of millions of users across Windows, Mac, Android, iOS, and the web.

Outlook add-in on a surface laptop displayed on concrete desk next to a vase

Integrate your business solutions into Outlook

A financial worker using Outlook to compose an email using event-based add-ins

Use the power of event-based add-ins

Enable users to access your solutions via common Outlook actions such as composing a new email, adding a recipient, or adding an attachment.

A woman using Outlook while working from home

Enable better collaboration in a hybrid working environment

Help your users to be more productive in hybrid or remote environments by sending better emails. Smart Alerts events such as OnMessageSend and OnAppointmentSend allow your users to improve their emails and meeting invites before they're sent.

A woman using an Outlook add-in on her iPhone

Build contextually rich email experiences across platforms

Outlook add-ins provide the right information and expose relevant tasks in the context of an email communication at the right time, such as when you're composing or reading an email. And, Outlook add-ins work across Windows, Mac, Android, iOS, and the web.


Learn. Share. Connect. Grow.

Join the Microsoft 365 Developer Program

Join the Microsoft 365 Developer Program

Get an instant sandbox preconfigured with sample data and start developing on the Microsoft 365 platform.

Developers seated around a table participating in the Microsoft 365 developer community

Connect with our developer community

Don't reinvent the wheel. Learn, share and contribute with others on how to build apps for Outlook and the Microsoft 365 platform.

What's new in Outlook development

Back to top