I'm looking for a reference of URL parameters that can be passed into Office365 to be used as links for the MAILTO: protocol and other uses.

For instance, Outlook Web App in Office 365 will take the following URL string:

https://outlook.office.com/?path=/mail/action/compose&[email protected]

and open a new mail body with [email protected] in the "To:" field.

Is there a complete reference for ALL query strings and URL parameters?

1 Answer 1


How to compose a New Message or Event and Populate fields in Office365

There is support available to programmatically invoke OWA mail and calendar event compose form. Because this is based on URL parameters, there are a number of limitations, including the limit on URL length of around 2048 chars which essentially makes it not adequate for ‘reply’ scenarios (where you are likely going to want to append significant amount of content in the message body).

Compose new Message (Mail):

You need to append parameters to the Office365 OWA URL

| Parameter | Value |
| path | /mail/action/compose |
| subject | Customer Service Request |
| body | Add your request here |
| to | [email protected] |

cc is not supported at this point.

For example:


https://outlook.office.com/?path=/mail/action/compose&[email protected]&subject=Customer Service Request&body=Add+Your+Request+here

Compose a new appointment (Calendar):

You need to append parameters to the Office365 OWA URL

| Parameter | Value |
| path | /calendar/action/compose |
| subject | Sushi Training |
| body | Remember to bring your force! |
| location | Convention Center |
| startdt | 2016-02-29T19:00:00 |
| enddt | 2016-03-01T00:00:05 |

For example:



Remember that for more complex scenarios, you have available Outlook API, mail, calendar and more


The user experience when accessing the previous URLs is immersed in outlook web app (after login if required), and the user has the ability to open the mail or event through the right upper icon

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Some screenshots to show the experience (Desktop – Firefox, Chrome, Explorer, Edge).

image for the Calendar event example image for the Calendar event example

image for the mail example image for the mail example

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