Despite Rich Communication Services being touted as the next generation of SMS, it is taking time for all users to access it. In order to run on your phone, your network, operating system, and your messaging application must support it through an API. Google has already bypassed operators when adding an RCS API for Google messages, but it is only available for that app. Now it seems that in the latest app update third party apps can request the RCS API, but it seems to be limited to Samsung apps only.
XDA Developers shares An APK teardown of the latest Google Messages app. At first, they could see strings indicating that third-party messaging apps will be able to send SMS, MMS, or RCS through the Google Messages app. But upon closer inspection, it appears to only be found in the Samsung version of the Messages app that is deployed on Galaxy devices. And digging deeper into the code, it appears this is only available for select Samsung apps.
The type of permission is listed as “dangerous”, but that simply means that the confirmation will be displayed to the user in order to grant that permission to the requesting application. The approval will have to be given initially and later they can “send messages without any additional approval”. Having Google Messages handle message routing instead of the third-party app may seem inconvenient at first, but it also means that they will have to go through Google’s chat service, the most widely used RCS implementation.
Since only some Samsung apps can access this RCS API, it is most likely targeting Samsung smartwatches and tablets so they can send SMS, MMS and RCS via Google messages. This is most likely part of Samsung’s efforts to have call and message continuity across all Samsung devices. The code verifies the package name and signature of the requesting application and a flag allows the application to access the API.
Google or Samsung have yet to make any announcements regarding the Android Messages API. Hopefully this will happen soon and not just for Samsung apps, but other third-party messaging apps as well.