ProgrammableWeb recently published an analysis of the top free and paid Music APIs available in our directory. Please click here to read the full analysis.
Our API directory now includes 160 music APIs. The newest is the Spotify Apps API. The most popular, in terms of mashups, is the Last.fm API. We list 206 Last.fm mashups. Below you'll find some more stats from the directory, including the entire list of music APIs.
In terms of the technical details, REST and XML lead the way. There are 131 music REST APIs and 14 music JavaScript APIs. Our directory lists 110 music XML APIs and 90 music JSON APIs. 
The most common tags within music are 26 social music APIs, 18 music events APIs and 16 music search APIs
On the mashup side, we list 460 music mashups. We named Soundtracking as mashup of the day two weeks ago.
For reference, here is a list of all 160 music APIs.
5gig API: Concert listing service.Track this API
7digital API: Music downloads store.Track this API
8tracks API: Music playlist creation service.Track this API
Acoustid API: Audio fingerprinting service.Track this API
AllCDCovers API: Music graphics service.Track this API
ArtistData API: Artist information retrieval service.Track this API
Audiobaba API: Music search and recommendation engine.Track this API
AudioBox.fm API: Cloud-based audio management.
AudioMicro API: Stock music and sound effects provider.Track this API
Audiosocket MaaS API: Music licensing agency.Track this API
Bandcamp API: Music information including track data and lyrics.Track this API
Bandsintown API: Music concerts and recommendations service.Track this API
Baskytara API: Bass guitar web Portal.Track this API
BBC Music API: Music information service.Track this API
Beatport API: Electronic music downloads.Track this API
Billboard API: Music chart service.Track this API
Blip.fm API: Social music service.
BMAT API: Music search and recommendation service.Track this API
CCHits API: Creative Commons Music Podcasts Service.Track this API
CD Universe API: Online CD and music retailing service.Track this API
ChartLyrics Lyric API: Lyrics database search service.Track this API
CompareDownload API: Online music download store.Track this API
Console.fm API: Electronica music streaming service.
Dance-Tunes API: Electronic music downloads.Track this API
DAR.fm API: Digital audio recording service.
Decibel API: Music metadata provider.
Digital Music Engine API: Music catalog and download service.Track this API
Digital Podcast API: Podcast search.Track this API
Discogs API: Music database.Track this API
DoStuffMedia API: Music festival data lookup service.Track this API
Echo Nest API: Music services for professionals.Track this API
eMusic API: Music and Audiobook Search Service.Track this API
Eventful API: Local events discovery and demand.Track this API
ExtensionFM API: Music discovery tool.Track this API
Faces.com API: Photo and media sharing service.
fanart.tv Music API: Music fan art repository.
Free Music Archive API: MP3 archive.Track this API
FreeCovers.net API: Album cover archive.
Freedb / CDDB API: Online CD catalog service.Track this API
Freesound API: Music and sound search service.Track this API
Fusicology API: Music and progressive entertainment hub.Track this API
GigJunkie API: Music events services.Track this API
Gigulate API: Music blogging service.Track this API
Grooveshark API: Interact with Grooveshark music data.Track this API
Gruvr API: Live music and concert information.Track this API
Guitar Chord API: Music utility service.Track this API
idiomag API: Musical artist information service.Track this API
iHeartRadio API: Radio station search and player.Track this API
iLike API: Music streaming and playlist service.Track this API
Imeem API: Social networking and media service.Track this API
InstantEncore Maestro API: Classical music community.Track this API
Internet Video Archive API: Movie trailers, music videos, and game trailers service.
INZU API: CMS for the music industry.Track this API
IODA Open API: Online Music Distribution Database.Track this API
Ipernity API: Media sharing service.Track this API
iRadeo API: Internet radio service.Track this API
iTrackmine Simple API: Collection sharing service.Track this API
JamBase API: Live music and concert information.Track this API
Jamendo API: Access to a range of music related information.Track this API
KillerTours.com API: Band and Concert Search Tool.
Last.fm API: Online radio service.
LazyTune API: Music search services.Track this API
LicenseQuote API: Music licensing service.Track this API
Live Nation Event Data API: Live music and concert information.Track this API
Livekick API: Concert and events recommendation service.Track this API
Lollapalooza API: Music event reference.Track this API
LyrDB API: Lyrics Database.Track this API
Lyricsfly API: Song lyrics search engine.Track this API
LyricWiki API: Song lyrics data service.Track this API
Maestro.fm API: Online music service.
Magnatune API: Music subscription and streaming service.Track this API
Malmöfestivalen API: Malmö Festival schedule and information.
Medianet Open MP3 API: Music search services and music store.Track this API
MeeMix API: Music recommendation service and discovery.Track this API
Metallizer API: Heavy metal album and song generator.Track this API
Mixcloud API: Radio, DJ, and Podcast Hosting Service.Track this API
Mobile Roadie API: Mobile application service for musicians.Track this API
Motime API: Ringtone search utility.Track this API
Motime Chart API: Ringtones services.Track this API
Mougg API: Music storage and streaming service.Track this API
MP3Tunes API: Music services.Track this API
MTV API: MTVN Content API.Track this API
Musescore API: Sheet music sharing service.Track this API
MusicBrainz API: Music metadata community service.Track this API
MusicDNS.org API: Music fingerprinting service.
Musicmetric API: Music industry data tracking service.Track this API
MusicMobs API: Social music service.Track this API
MusixMatch API: Song lyrics search engine.Track this API
Myplaylist API: Photo slideshow for music services.Track this API
Napster API: On-demand streaming music and content.Track this API
National Student Radio Chart API: Popular music information service.Track this API
Next Big Sound API: Artist and Band Statistics.Track this API
Noteflight API: Online music writing service.Track this API
NPR API: US National Public Radio.
Official.fm API: Online music management service.
Omnifone MusicStation API: Multi Platform music service.Track this API
openDada API: Social music service.Track this API
OpenStrands API: Music recommendation and discovery.Track this API
Orb API: Digital media remote access and management.Track this API
Peachnote API: Music score search engine and analysis platform.Track this API
People's Music Store API: Music store.Track this API
Phish.Net API: Phish fan site.
Planning Center API: Ministry Planning Tools.Track this API
Playme API: Music streaming, download, radio and playlist service.Track this API
PlayPhone API: Partner with Playphone to offer Mobile content in over 20 countries.Track this API
Pond5 API: Stock media marketplace.Track this API
RadioSherpa API: Real-time radio program information.Track this API
RadioTime API: Music and talk radio service.Track this API
Rdio API: Social Music Service.Track this API
RealRadios API: Streaming internet radio service.Track this API
Rhapsody API: Online music services.Track this API
Rovi Cloud Services API: Digital entertainment technology.Track this API
Rumblefish API: Music licensing service.Track this API
SampleSumo MeloTranscript API: Music transcription service.Track this API
ScreenTunes API: Media based search engine.Track this API
SeeqPod API: SeeqPod Music Discovery.Track this API
Seevl API: Music discovery service.Track this API
setlist.fm API: Wiki-like service to collect and share setlists.
SNOCAP API: Digital music marketplace.Track this API
Song.ly API: Music discovery service.
Songbird API: Music and media streaming service.Track this API
Songkick API: Music concert and event community.Track this API
Songsterr API: Tablature service for guitar tabs.Track this API
Songza API: Music popularity and user playlist services.Track this API
SonicLiving Concerts API: Online concert listing service.Track this API
Sonos Music API: Multi room audio system.Track this API
Sony Ericsson Track ID API: Music Recognition.Track this API
SoundCloud API: SoundCloud is a social audio platform.Track this API
Sourberry API: Sourberry Internet Radio Status Tool.Track this API
Spotify Apps API: Music search and streaming service.Track this APITrack this API
Spotify Metadata API: Music search and lookup service.Track this API
Stereomood API: Internet radio service.Track this API
Streamfinder API: Streaming radio station directory.Track this API
Streampad API: Music streaming service.Track this API
Stupeflix API: Video creation service.Track this API
Subsonic API: Music streaming service.Track this API
TasteKid API: Taste discovery service.Track this API
Thounds API: Music creation and sharing service.Track this API
Thrillcall API: Music concert, tickets and tour information.Track this API
Thumbplay API: Mobile. Music. Money. Sell digital media to over 200 million mobile phones from any application, widget or website.Track this API
Ticketfly API: Music events and ticketing service.
Tinysong API: Music sharing service.Track this API
Topspin API: Direct to fan marketing platform.Track this API
TuneFind API: Movie & TV Show Music Database Service.Track this API
Tunelog API: Music metadata management.Track this API
tunesBag API: Music storage, streaming, and sharing.Track this API
Twones API: Social music service.Track this API
twt.fm API: Twitter music sharing service.
Unsigned Band Web Music API: Music streaming service and music database.Track this API
USA Today Music Reviews API: Music reviews service.Track this API
VexFlow API: Web-based music rendering service.Track this API
Vokoder.fm API: Music Storage, Sharing, and Selling Service.
We Are Hunted API: Social music data sharing.Track this API
WebJay API: Music playlist management.Track this API
Winamp API: Customizable music player.Track this API
Yahoo Audio Search API: Music search services.Track this API
Yahoo Music API: Music and musician info and videos.Track this API
Yahoo Music Engine API: Desktop music player.Track this API
Yes Broadcast DB API: Radio station search, now-playing, logs and charts.Track this API
Zatune API: Arabic music API.Track this API
