# MMS channel properties

There are MMS channel-specific properties that can be used when making calls to the Conversation API. These properties can be listed under `channel_properties` in the message request.

The relevant MMS channel properties are detailed in the table below:

| Property name | Property value |
|  --- | --- |
| `MMS_SENDER` | Required on MMS channel, specifies the shortcode or longnumber to use as the sender. |
| `MMS_STRICT_VALIDATION` | Whether or not you want the media included in your message to be checked against [Sinch MMS channel best practices](https://developers.sinch.com/docs/mms-bestpractices). If set to true, your message will be rejected if it doesn't conform to the listed recommendations, otherwise no validation will be performed. The default is false. |