The Decibel C# SDK allows developers to query the Decibel API to return music metadata. Calls to the Decibel API are made through query objects, which take care of all the logic involved in running a REST query, including deserializing the results to handy result objects. These can then be used to integrate Decibel data into an application.
Last.fm besides being one of the most popular online radio and music communities, also has one of the most popular online music APIs. Possibly the most popular. Each month we continue to see a variety of new music-themed mashups added to our directory built on the Last.fm API. In the first three weeks of this month alone there have been 5 more Last.fm mashups added. That means that out of 231 music mashups at least 84 use the Last.fm API. And not that developers don't have other options given that there are 44 music APIs to choose from.
ProgrammableWeb lists many popular Music APIs in the directory including Last.fm, 7digital and Spotify Metadata. This post features a few really creative, entertaining mashups that use a few popular Music APIs.
Shuffler.fm is a web based music magazine that allows users to browse music on the web through music sites and blogs. It allows them to discover new music and keep an eye on current trends, with the help of those in the know.