If you're using the Vimeo OTT API to display your content on a third party site, you will be using the Authorizations API to generate an embeddable iframe that displays your video content. You may want to restrict that embed to only be viewable on a select number of domains.
To restrict where your content can be embedded, navigate to Manage -> Site -> Advanced and scroll down to the "Allowed Embed Hosts" area.
Changes made here will have no impact on video playback in your Vimeo OTT Branded Apps or on your Vimeo OTT powered website but will allow you more control over where embeds can appear.
Using this field you can specify which domains should be allowed to embed your content. Add each domain in a comma delimited list here. Remember "www.mysite.com" and "mysite.com" are different! Be sure to enter both. The end result will look like "www.mysite.com,mysite.com"
When using the Authorizations API, you must add "&vimeo=1" to the iframe embed src that is returned in order for your embed hosts to be respected.