As you might expect, there's no quick answer. Both offer features that are about on parity, and each have their own advantages and shortcomings, which is to be expected. What's interesting is what those differences are, to see what's truly novel about what Yahoo! Music has to offer.

If you already hip to the whole Last.fm thing, you can skip down to the next section for the gritty details.

A Brief History of Last.fm

Last.fm was one of the first and most notable music APIs, launching right as the Web 2.0 thing was hitting its stride in late 2005. It's greatest strength is its ability to track its user's listening habits real-time, through a process called "Scrobbling". Over a just a few weeks, a user's personal listening habits are matched against everyone else's to see what else you might be interested in. Back in June, Last.fm announced the second iteration of their APIs, which further beefed up its offerings with support for tagging and user sessions. As a long-time Last.fm user, I can vouch for their recommendation engine: no matter how obscure or indie my musical tastes get, it always has great recommendations.

Enough about that, on with the gritty details:

The Gritty Details

Protocols	REST, XML-RPC	REST
Formats	Plaintext, XML, XSPF, RSS	XML, JSON, RSS
API Groups	Album, Artist, Event, Group, Library, Tag, Track, User	Artist, Category, Image, Rating, Release, Station, Track, Video
Example Request	http://ws.audioscrobbler.com/2.0/?method=album.getinfo&artist=Jamiroquai&album=Dynamite	http://us.music.yahooapis.com/release/v1/list/artist/252859
Dev Key Required?	Yes (v2.0 only)	Yes
Usage Limit	5 reqs / sec / IP Address	5,000 reqs / day / App ID
Documentation	http://www.last.fm/api/intro	http://developer.yahoo.com/music/api_guide/

As far as functionality goes, there's a lot of overlap between these two APIs. Both offer search APIs for Artists, Albums, Tracks, and Users--the bread an butter of any respectable music catalog. Last.fm, being mostly user-generated, categorizes its music using a tag-based folksonomy, whereas Yahoo! takes a top-down approach by using categories, which include genres, eras, and themes.

In terms of unique features, the Last.fm API exposes its database of upcoming performances by artists and other events. It also has supports a wider range of user interactions, including the ability to submit listening information ala "Scrobbling".

On the other hand, Yahoo! Music, is unrivaled in its offering of music videos, and the ability to embed videos directly into web pages is a killer feature. Although less flashy, Yahoo! Music supports spelling recommendations to disambiguate results, which in practice, make it a lot more usable.

Both APIs offer a means of getting and manipulating user data. Last.fm uses session-based authentication tokens, and Y! Music does in its own way, via BBAUTH.

Logistically, there are quite a few differences in how developers can use either of the APIs.

Although the previous version of the Last.fm allowed use without an API key, the new version requires it. Fortunately, their terms of use remain fairly liberal, providing API keys for both commercial and non-commercial use. As far as usage caps, applications can make up to 5 requests per IP address per second.

The terms of use for Y! Music are just like any other Yahoo! API, with the big exception being that use of the Music API is limited to non-commercial use. Requests require an App ID, with which up to 5,000 queries per day can be made.

Lastly, although for the most part a matter of taste, each has their own way of formatting REST requests.

The REST architecture for Last.fm resembles a familiar, object-oriented approach:
http://ws.audioscrobbler.com/2.0/?method=album.getinfo&artist=Jamiroquai&album=Dynamite

By contrast, the relative cryptic nature of the Y! Music API takes a little getting used to, with a typical request looking like:
http://us.music.yahooapis.com/release/v1/list/artist/252859

Rock out with Ruby

Lucky for you, over the course of researching the Y! Music API, I wrote a pretty flexible Ruby library, which will be available as a gem in the next couple of days. You can get the latest version at the project's Github page.

To give you an idea of what it's like, here's a simple example:

require 'yahoo-music'

include Yahoo::Music

Yahoo::Music.app_id = "..." # Put Your App ID Here


artist = Artist.new("Beirut") # Searches by name and uses first result

album = artist.releases.detect{|r| r.title == "Flying Club Cup"}

puts album.title

puts album.artist

puts "Release Date:" + album.released_on.strftime("%m/%d/%Y")

puts

puts "Tracks"

artist.tracks.each_with_index do |track, i|

  puts "\t%d %s \t%2d:%2d" % [i, track.title, track.duration / 60, track.duration % 60]

end

Pretty awesome, right? Although the library's still in early development, and doesn't completely cover all of the functionality of the full API yet, feel free to check it out for yourself and tell me what you think.

D.S. al Coda

Actually, talking about libraries is less of a digression than a good stopping-off point for this article. Like I said before, both Last.fm and Y! Music are both excellent music APIs that are definitely worth a look. The best place to start is to just dive into some code and write something.¹ I hope that this deeper dive not only gives you a context for what they can do, but also inspire you to get out there and make something awesome.

♪ Happy Hacking,

Mattt Thompson
YDN Tech Evangelist

¹ If you're looking for a good Ruby library for Last.fm, be sure to check out John Nunemaker's Scrobbler gem. It has served me well in the past, and was a great source of inspiration when I made my Y! Music library.