Not all free movie apps are compatible with Chromecast, as it depends on the specific app and its features. While some free movie apps have built-in Chromecast support, allowing you to cast the content to your Chromecast-enabled device, others may not offer this functionality. It's best to check the app's description or user reviews to determine if Chromecast compatibility is mentioned. Additionally, you can try using the Google Home app to cast your device screen to Chromecast if the app itself doesn't have direct support.