Last November, we reported that Spotify was morphing into a platform, integrating apps inside the music-streaming service, such as Songkick, Pitchfork  and Billboard.

It has been gradually rolling out more apps in the four months since, and today it has been announced that ‘music intelligence platform’ The Echo Nest and Spotify have integrated their APIs, making it easier for any Spotify app developer to tap The Echo Nest’s music intelligence technology.

The Echo Nest’s offering is based on their database of around 30m songs and 1.5m artists, which is automatically derived using Web crawling, data mining and digital signal processing. The platform enables developers and media companies to integrate music data across their products.

Last June the company partnered with 7digital and MusicBrainz, which culminated in the launch of Echoprint, an open source version of Shazam. And in August, it announced another partnership with eMusic, a digital music service for independent music collectors.

This was followed by a Twitter hook-up in January to let developers link musicians’ tweets to their music, then Seatwave got in with the The Echo Nest too, so that developers could integrate ticketing features into their apps.

SpotifyApps 520x265 Any Spotify app developer can now tap The Echo Nests music intelligence technology

So it has been a busy year for the Massachusetts-based company, and this latest partnership will see The Echo Nest integrate Spotify IDs into Rosetta Stone. This service translates song and artist identifiers between music content and data APIs, as we’ve seen with the likes of Twitter, MusicBrainz and Seatwave, and also makes it easy to leverage The Echo Nest’s core music discovery and personalization features within a Spotify app.

Back in December, Spotify UK managing director Chris Maples called its app platform “arguably our biggest announcement since we launched”, and perhaps for good reason. In the first three months after launch, music fans listened to over 1,500 years of music within them.

Before this announcement today,The Echo Nest was already powering Spotify Radio, and a number of third-party apps running outside the main Spotify client, as we reported with SpotON Radio earlier this year, and with Echofi.

The Echo Nest was founded in 2005 from the dissertation work of two students at the MIT Media Lab, and in October 2010, it secured $7 million in funding to drive its growth.

iHeartRadio 520x220 Any Spotify app developer can now tap The Echo Nests music intelligence technology

To date, 220 music apps have been built on The Echo Nest platform, and it claims that 100,000,000 music fans are reached via these apps.

So…every Spotify app that relies on playlisting, personalization, or music discovery will be able to tap The Echo Nest’s data platform. We’ll likely be hearing a lot more from this company this year.