The SoundCloud Ruby SDK by SoundCloud offers methods to handle authorization and execute HTTP calls. Examples demonstrate how to print links of the 10 hottest tracks, work with OAuth2, initialize a client, and add a track to a playlist.
As much as mobile backend-as-a-service (BaaS) platforms free up developers from having to worry about the infrastructure that support their applications, they do generally come with a downside; most of them lock the developer into a particular cloud platform. With that issue in mind, FeedHenry created a namesake BaaS platform that took advantage of Node.js to create a BaaS platform that developers could deploy and ultimately move to any cloud platform of their choice.
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.