Flush with their recent funding rounds, the battle is on between streaming music services Deezer and Spotify for users, new territories and now app developers.

Spotify’s desktop app platform and iOS API are well established, but today Deezer is taking the wraps off its App Studio – the second phase of its ‘Open Deezer’ initiative to court external developers.

App Studio is a two-pronged thing, aiming to help developers integrate Deezer into their own apps and sites, while also bringing “feature-rich apps inside Deezer.com”. The company is also launching a Facebook-style ‘App Centre’ to help its users discover web, desktop, iOS and Android apps built using Deezer’s APIs.

Apps on board for launch include PIAS, Shuffler.fm, eDJing, Twusic and some existing apps created by Deezer’s own staff or developers at its hack days: Wallzr, Spotizr and iPhone game Lalilala.

Spotify still has the more high-profile catalogue of startup and artist apps, but the competition between the two in the coming months for new apps should be fun. We’re wondering how many developers and labels will try to simultaneously launch on both.

The news came as Deezer bumped up its discovery features for users, including a partnership with Songkick to use the latter’s concert recommendation API to suggest gigs based on people’s usage. It’s also updated its iOS and Android apps with more social discovery features.

Now industry eyes will turn to Spotify, whose ‘What’s Next’ event on 6 December will show us its next steps in discovery (and possibly in apps too).