This library in Java language for the Spotify Echo Nest API provides access to the Track Analysis API. With this resource, developers can obtain track's loudness, mode, key, tempo, signature, detailed beat structure, harmonic content, and timbre information. See examples with hottest songs, static playlists, and similar artists at https://github.com/echonest/jEN/tree/master/src/com/echonest/api/v4/examples
For staying up to date with band tour dates, live venue information and more, Pollstar has it covered. It's a trade publication that covers music industry information on a worldwide scale. What's pretty cool is that Pollstar provides an API that allows third party developers access to the full event database, enabling them to include Pollstar data on other websites and applications.
Think the social web is big? When it comes to connecting Twitter, Facebook and others to the rest of the web, APIs are there to do the heavy lifting. The category continues to explode, already surpassing the number of social APIs added last year. Our directory currently lists 558 social APIs, with nearly 200 added this year.
Something awesome is happening in the world of music and the web. But first, some primer.
Rdio is one of the few music subscription services that do a tremendous amount of things right, including having its robust Rdio API. For $5 a month, you can get all of the music you want, have collaborative playlists, share content to Facebook and Twitter, and keep up with what your friends are listening to. For $10, you can do all that and store the music to your phone for offline or higher quality enjoyment.