Microsoft Outlook Dev Center | APIs and app development

Build powerful apps for Outlook and Microsoft 365

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

Learn more about building apps for Outlook

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.

Configure your Outlook add-in for event-based activation Enable single sign-on (SSO) in Outlook add-ins that use event-based activation

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.

Use Smart Alerts events in your Outlook add-in
Create an Outlook add-in for an online-meeting provider

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.

Create an Outlook add-in activated in compose forms
Create an Outlook add-in activated in read forms