The new feature allows people to share playlists and songs with friends inside of conversations on Messenger.
The integration doesn't allow you to actually play Spotify music inside of Messenger, at least not yet, but it does allow you to share tracks, playlists and artists within message threads. You can add Spotify tracks to messages from the "..." menu and selecting it from the list of apps.
Once you've selected Spotify, you can search the app as you normally would to find an artists or playlist or song to share back to Messenger. If the recipient has the Spotify app on their device, they can open the Spotify content directly in the app. Shared songs will begin playing automatically once Spotify opens.
Messenger spotify
Messenger spotify
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Image: Facebook
You don't need to be a premium subscriber in order to take advantage of the new feature, though it is limited to Messenger's iOS and Android app. Alternatively, you can also share directly from Spotify to Messenger from the app's share menu (Share —> Send To —> Facebook Messenger.)
Though Facebook has been steadily adding more third-party services to Messenger, integration with Spotify marks the first time the social network has added a major music service. Facebook also recently added a transportation section, with support for Uber and other transit providers coming soon.
With 800 million monthly users and counting, it's likely we'll see a lot more major services coming to Messenger in the near future.
Yahoo