Running an Outlook add-in in an Office 365 account
The Outlook add-in model is already available for Office 365 developers. You can use your existing Office 365 subscription to build an add-in targeting Office 365 right away. The same add-in model and APIs will work if you later choose to target Outlook.com as well.
If you don't have an Office 365 subscription, you can get up and running quickly by signing up for an Office 365 Developer subscription. That gives you a single user, and automatically provisions a Developer SharePoint site for you at <your-domain>.sharepoint.com (which you'll need if you plan on using the Napa development tool). An Office 365 Developer subscription is free for one year if you sign up for the Office Developer program.
Alternatively, if you need more users, you can instead sign up for a 25-user free trial of the Office 365 Business subscription. Either way will work!
Here are a few quick ways to get started with an Outlook add-in.
You can use the Microsoft Office Project Generator, a Yeoman generator for creating Office add-ins. All you need is Node.js, bower, and the generator. Head over to their page for instructions.
You can quickly clone our existing add-in code sample on GitHub and host it on your own web server.
Copy the command-demo directory from the project to your web server. Note: if you're using the Microsoft Office Project Generator, you can copy the command-demo directory over the files created by the generator, and use the included gulp serve-static command to create a local webserver for testing purposes.
Open command-demo-manifest.xml in a text editor and update all instances of YOUR_WEB_SERVER to the base HTTPS URL of the directory on your web server where you deployed the add-in files.
Logon to Outlook Web App. Click on the gear cog () in the upper right corner of the page and click on Manage add-ins.
On the Manage add-ins page, click on the '+' icon, select Add from file. Browse to the command-demo-manifest.xml file included in the project. Click Next, then click Install. Finally, click OK.
Return to the Mail view in Outlook Web App.
Use Outlook 2016 to try the add-in command functionality of the add-in.
To try the read mode functionality of the add-in, select or open any message and try the buttons on the ribbon.
To try the compose mode functionality of the add-in, create a new message and try the buttons on the ribbon.
Use Outlook Web App to try the add-in's functionality in clients that do not support add-in commands.
To try the read mode functionality of the add-in, select any message and launch the Add-in Command Demo add-in from the add-in bar.
To try the compose mode functionality of the add-in, create a new message. Click the Add-ins button and choose Add-in Command Demo.