I am trying to build an mobile application which can use Spotify APIs and play music (Not remote control app) just like Spotify. So far I've implemented authentication, getting playlists and tracks using web APIs. Now I can not see any API which can help me play music (or maybe I missed it). Could you please help me to achieve or tell me if this service is not provided by you?
Unfortunately, what you want to do does not seem possible.
The Spotify SDK allows your application to interact with the Spotify app running in the background as a service. The capabilities of this API include getting metadata for the currently playing track and context, issuing basic playback commands and initiating playback of tracks.