> For the complete documentation index, see [llms.txt](https://developer.perculus.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.perculus.com/v2-en/services/attendee-management/creating-and-updating-attendees/upsert-by-user.md).

# Upsert by User

API supports and **encourages** adding users to sessions as attendees with the help of User GUIDs. Below is all the accepted parameters for adding a user to a session as an attendee:

<table><thead><tr><th>Parameter</th><th>Type</th><th width="106">Required</th><th>Default</th><th>Description</th></tr></thead><tbody><tr><td>user_guid</td><td>string</td><td>Yes</td><td>n/a</td><td>GUID of the user that will be added to the session as a participant</td></tr><tr><td>role</td><td>string</td><td>No</td><td>See hint below</td><td>Role of the attendee(<a href="/pages/UTVEaKGzw0Q9EmCFXDq1">see</a>)</td></tr><tr><td>email</td><td>string</td><td>No</td><td>See hint below</td><td>Attendee's email address</td></tr><tr><td>name</td><td>string</td><td>No</td><td>See hint below</td><td>Attendee's name</td></tr><tr><td>surname</td><td>string</td><td>No</td><td>See hint below</td><td>Attendee's surname</td></tr><tr><td>mobile</td><td>string</td><td>No</td><td>See hint below</td><td>Attendee's mobile</td></tr></tbody></table>

{% hint style="warning" %}
If the optional parameters are not sent, they will default to the user's ones.
{% endhint %}